diff --git "a/Data/transcripts/6ZrlsVx85ek_20241225194758.txt" "b/Data/transcripts/6ZrlsVx85ek_20241225194758.txt" new file mode 100644--- /dev/null +++ "b/Data/transcripts/6ZrlsVx85ek_20241225194758.txt" @@ -0,0 +1,3869 @@ +ANDREW HUBERMAN: Welcome to the +Huberman Lab podcast, +where we discuss science and science +-based tools for everyday life. +[MUSIC PLAYING] +I'm Andrew Huberman, +and I'm a professor of neurobiology +and ophthalmology +at Stanford School of Medicine. +Today, we are discussing hair. +Hair is a topic that occupies +the minds of many people. +There are people that are losing their +hair and want to halt or +reverse that loss of hair. +Today, we will talk about all the ways +that science has taught us we can +slow or even reverse hair loss. +I confess that researching today's topic +was a particular joy for me not because +I'm obsessed with hair, +mine or the hair of others, +but because hair turns out to be +fascinating from the perspective +of cellular biology and stem cells, +which is a topic that I've long been +interested in and that for much +of my career I focused on in +the context of development. +When your brain and your nervous system +develop, it develops from a small batch +of cells that turns +into many trillions of cells. +It does that by cell replication, +something that we call the cell cycle. +We'll talk a little bit about +this and so-called mitosis today. +I promise not to get into too much detail. +But what makes hair so very interesting +from a biological standpoint is that every +hair, every single individual strand +of hair has its own little stem cell +niche, meaning its own little pocket down +there in the follicle in which specific +stem cells give rise to those hairs +for different durations of time, +depending on the hair, +where it is on your body, et cetera. +For instance, the hairs on your head will +undergo ongoing growth +for 4-6 or even 8 years. +Were you to not cut your hair, +it would continue to grow. +One single hair would continue to grow. +I guess we could say all the hairs will +continue to grow for up to 8 years. +That is very different from, for instance, +your eyebrows, which have a much shorter +period of hair growth lasting +on the order of months. +That's why you don't see people with +eyebrows that extend down to their waist. +But you can see people with hair on their +head that extends down to their +waist if they don't cut it. +Now, that discrepancy illustrates for us +just how incredible hair follicles +and the stem cells that reside within +hairs are and their enormous potential +to give rise to these things that we call +hairs, which are simply proteins +of varying length. +Today, we are going to address what +determines the length of a hair or rather +what determines how long a hair continues +to grow before it ceases growing +and eventually falls out. +We're going to talk about what regulates +those stem cells, +what allows them to continue to produce +hair or cease producing hair. +As we do that, +you will learn all the biology in clear, +simple terms, +regardless of your background, +that will really set the stage +for understanding what we'll also talk +about, which is how to slow hair loss or +halt hair loss entirely or +even reverse hair loss. +We will talk about hormone -related +hair loss in both men and women. +We will talk about some of the mechanical +and stress -related +influences on hair loss. +We will talk about the chemical +and mechanical approaches to halting +and reversing hair loss, +everything from minoxidil to +dutasteride to ketoconazole +to microneedling to thyroid, +estrogen, IGF-1 pathways. +Again, all made very clear regardless +of whether or not you have +a background in biology or not. +I will also dispel some of the common +myths about balding and hair replacement. +If you've heard, for instance, +that you inherit your patterns of balding +from your mother's father, +that is not true. +Although it is true that you do inherit +certain genes that influence whether or +not you have a predisposition to balding +in particular parts of your head, +and believe it or not, +even in particular parts of your body. +But it is not the case that you can simply +find a photo of your mother's father, say, +age 50, or age 60 or 75, +and determine whether or not you'll have +the exact same pattern of hair loss. +That's a myth that I'd like +to dispel right here and now. +I will dispel some of the other myths +about hair loss, hair replacement, +and hair regrowth as well. +Before we begin, I'd like to emphasize +that this podcast is separate from my +teaching and research roles at Stanford. +It is, however, +part of my desire and effort to bring zero +cost to consumer information about science +and science-related tools +to the general public. +In keeping with that theme, I'd like +to thank the sponsors of today's podcast. +Our first sponsor is Helix Sleep. +Helix Sleep makes mattresses and pillows +that are the absolute highest quality. +I've talked many times before on this +podcast about the fact that sleep is +the foundation of mental health, +physical health, and performance. +Helix understands that everybody's +sleep needs are slightly different. +If you go to their website, +you can take a brief quiz, +and that quiz will ask you questions such +as, do you sleep on your back, +your side, or your stomach? +Maybe you don't know which is fine. +You can simply answer, I don't know. +Or do you tend to run hot +or cold during the night? +Helix takes those answers and then matches +you to a mattress that's +ideal for your sleep needs. +For me, it matched me +to the dusk, D-U-S-K mattress. +I've been sleeping on a dusk mattress +for over 2 years now, and my sleep has +been better than it ever was previously. +If you're interested in upgrading your +mattress, go to helixsleep.com/huberman, +take their brief 2-minute sleep quiz, +and they'll match you +to a customized mattress for you. +You'll also get up to $350 off any +mattress order and two free pillows. +They have a 10-year warranty , and you get +to try out their mattress +for 100 nights risk-free. +They'll even pick it up for you +if you don't love the mattress. +But I think you will. +I certainly love mine. +Again, if you're interested, +go to helixsleep.com /huberman for up +to $350 off and two free pillows. +Today's episode is also brought +to us by HVMN ketone-IQ. +Ketone-IQ is a ketone supplement +that increases blood ketones. +I want to be very clear that I, like most +people have heard of the ketogenic diet, +but I, like most people, +do not follow a ketogenic diet. +That is, I'm not in ketosis. +However, most people don't realize +that you can still benefit from increasing +your blood ketones, which is what +HVMN ketone-IQ does. +I take Ketone-IQ prior to doing +really focused cognitive work, +so I take it once in the afternoon, +any time I'm going to prepare +for a podcast, or do a podcast, +or if I'm going to do some research, or +focus on a grant, anything that requires +a high level of cognitive demand. +That's because ketones are the brain's +preferred use of fuel, even if you're +not following a ketogenic diet. +I sometimes also use Ketone-IQ prior +to workouts, either resistance training +workouts or endurance +workouts such as running. +Again, that's because Ketone-IQ +by raising blood ketones +is really a brain fuel. +If you're interested in trying Ketone-IQ, +go to hvmn.com and use the code +Huberman to get 20% off. +Again, that's hvmn.com, and use +the code HUBERMAN to get 20% off. +Today's episode is also +brought to us by ROKA. +ROKA makes eyeglasses and sunglasses +that were designed with the biology +of the visual system in mind. +I've spent a lifetime working +on the biology of the visual system, +and I can tell you that your visual system +has to contend with an enormous number +of challenges for you to be able +to see clearly throughout the day. +For instance, when you go from a shady +area to a well-lit area, +your brain and eyes have to make a bunch +of different adjustments that eyeglasses +of the conventional type +don't always compensate for. +ROKA eyeglasses and sunglasses compensate +for those sorts of changes and all +the sorts of changes that your visual +system has to contend with, so you +always see things with crystal clarity. +The company was founded by two all-America +swimmers from Stanford, and initially, +their eyeglasses and sunglasses were +designed for sports performance. +Indeed, all of their eyeglasses +and sunglasses can be used +while running, while cycling. +They won't slip off your +face if you get sweaty. +They're extremely lightweight. +But they also have an enormous number +of varieties of eyeglasses and sunglasses +that are designed to be +worn at work or to dinner. +They have the classic performance +eyeglasses where makes you look +like a cyborg, if you like those. +They also have more conventional esthetics +that you'd be comfortable +wearing pretty much anywhere. +If you'd like to try ROKA eyeglasses or +sunglasses, you can go to roka.com, +that's roka.com, enter the code Huberman +to save 20% off your first order. +Again, that's roka.com, +enter the code Huberman at checkout. +Okay, let's talk about hair. +In researching this episode by talking +to experts in the biology of hair, +and the stem cells that exist in all of us +that give rise to our hair growth, +and the pigmentation in our hair, +and in talking to experts who understand +how to halt and even reverse hair loss, +that there is a tremendously +interesting biology surrounding hair. +But there's also an incredible +psychology around hair. +In fact, most people who experience even +marginal hair loss undergo +pretty severe anxiety. +Now, I confess this is not +something I can relate to. +I am losing my hair in certain places. +I'm 47 years old. +I've got a couple of patches up front +where there's very minimal hair. +I think that, as we'll later learn in this +episode, reflects a higher density of DHT, +dihydrotestosterone, receptors +at that particular location as +opposed to elsewhere in my scalp. +But keeping my hair is not something +that I've fretted about much of my life. +Yet as I was researching this episode, +I remembered an anecdote from my childhood +where my father told me, +and I think it was because I was stressing +about something, +I was trying to get to sleep, and he said, +"Don't stress . Calm +down." And here's why. +If you stress too much, +it can actually make your hair fall out. +In fact, I have a cousin who lay down one +night stressed, +and woke up the next morning , and +all of his hair was on his pillow. +I'll never forget that story. +I think he was trying +to get me to stress less. +I don't know if that story +made me stress less or not. +But in any event, I don't +know that that story is true. +I'm not going to challenge +the authenticity of that story. +I didn't have a chance to reach out +to my father and ask him to verify or not. +But as we will soon learn, +it is true that our psychological +well-being can impact both the coloration +,, or lack thereof and the +growth rates of our hair. +That's a real thing. +The reverse is also true, +which is that as hair starts to thin, or +fall out, or change color, +many people expect intense +anxiety or even depression. +This was not something +I was really aware of. +Perhaps that's just because I've always +kept my hair pretty short anyway. +I always assumed that if my hair started +to really fall out, +I would just shaved my head. +But that's me, and that's +not most people out there. +I think most people would +loathe to lose their hair. +In fact, given the enormous number, +probably up in the high billions +of dollars and euros and other currency, +of course, that people invest in trying +to halt or reverse their hair loss, +it's clear that hair is +very important to people. +What we know is that by age 50, +approximately 50% of all men and women +will have experienced significant enough +hair loss that they start to notice it. +And a large percentage, +up to 85% of those people will experience +some anxiety that leads them to go out +and try and either halt or +reverse that hair loss. +Now, why at age 50? +Well, an important point arises from that, +which is that the hair loss is not +occurring between the 49th +and 50th birthday. +Hair loss is ongoing +from about age 30 to age 50. +It's only by age 50, however, +that about 50% of people out there +start to notice that hair loss. +This is typically because +they'll be in a bathroom or looking +in a mirror and the lighting will be +bright enough that it permeates +the outer boundary of their hair. +They'll notice that their hair is +thinning in a particular location. +That's usually how this thing happens. +Again, our psychological states can impact +our patterns of hair growth or loss +and of course, patterns of hair growth, +but more typically, +hair loss and hair graying can +really impact psychological states. +This is a subject that people +take intense interest in. +Today, we're going to talk about how hair +normally grows, why it grows at the rate +, and for the duration that it happens to. +Then as we talk about ways to intervene +with that hair loss, +those biological mechanisms will come up +because they really provide a nice +framework for explaining why certain +treatments work more or less well or why +certain treatments might have certain side +effects or total lack of side effects. +It will also highlight a really key theme +that will come up several times in today's +podcast, which is that there are both +mechanical and chemical approaches +to slowing and reversing hair loss. +Mechanical approaches would be things as +simple as massaging the scalp, +but mechanical changes to the scalp can +cause either hair loss or +facilitate hair growth. +This is why things like microneedling are +so prominent in the context +of trying to reverse hair loss. +But again, there are also chemical +approaches to trying to halt +or reverse hair loss. +This relates to the fact that the hair +growth itself is strongly regulated +by hormones such as estrogen, +thyroid hormone, +insulin-like growth factor, +and that other hormones, in particular +the androgens, +so things like testosterone, +but mainly it's derivatives like +dihydrotestosterone are very much involved +in setting the stage for hair growth +by controlling how big or small that pool +of stem cells that gives rise +to hair growth is. +If any of the terms I just use are +confusing to you, don't worry, I will +make all of those very clear in a moment. +It's actually all pretty +straightforward and simple. +I'd like to just start by talking about +what hair is, how it grows, why it stops +growing, and why hair normally falls out. +Let's talk about the biology of hair. +In doing so, I also want +to talk about stem cells. +Now, keep in mind that when you hear +the word stem cells, you probably, +like most people, think about the sorts +of cells that people are getting injected +into their face to get rid of wrinkles, +or give them new skin, +or to give them more hair if it's +injected in the scalp, or into a joint +to repair a joint or a muscle. +Those stem cells are what we +call exogenous stem cells. +Exogenous, meaning from outside the body. +The stem cells that we're going to talk +about today are so-called endogenous stem +cell, cells that we all make +that can give rise to other cells. +That's really the definition +of a stem cell. +Stem cells are present in all of us +from the very beginning of life. +When sperm meets egg, that cell, +which we think of as the egg, +starts to duplicate, +it incorporates the DNA from the sperm +and the egg, of course, +starts to duplicate, +and then those cells give rise to more +cells and more cells and the ability +of all those cells to replicate and create +more cells are because those +cells really are stem cells. +Now, at some point we are a completed +body plan, as the biologists say. +We end up with a brain, and a spinal cord, +and limbs, and fingers, and livers, +and guts, and all the things that we need +in order to be a functioning human being. +Even though we're a baby at that time, +we haven't grown up, +we have all the bits that we're +going to have for our entire life. +At that point, many of the stem +cell populations disappear. +For instance, past puberty, +and probably earlier, you don't +get many more new brain cells. +You get a few, but you don't get many more +new brain cells because the brain doesn't +have many stem cell populations, +whereas other organs in your body maintain +little pockets of stem cells, +or in some cases, many stem cells that can +give rise to more and more +of that tissue across the lifespan. +Hair is one such tissue. +If we take a look at hair, +what we find is that, indeed, +there are these things that we call hairs, +but there are also stem cells, +and those stem cells are actually what +give rise to the hairs that we see +on the head of our scalp or that we +see on the surface of our body. +Right off the bat, +you should know that every single hair +that you have is there because you have +a stem cell population that is giving +rise to that particular hair. +Let's take a step back, or rather, +I should say, let's zoom in on one hair +and the stem cell population that gives +rise to that hair, because in doing so, +you're going to learn all the different +components that you can tap into if your +goal is to halt the loss of hairs or +to replace hairs that have +already been lost. +If we were to just zoom in at the level +of one hair, what you would find is +that that hair has what typically is +called a hair root, so that's +the portion below the skin. +When we say below the skin, +it means that it dives down into a narrow +trench, which is in the so-called +epidermis, which is this +outer layer of skin. +It also has a shaft. +The shaft is the part +that grows out above the skin. +What you see on somebody's head +or you see on their arm, +or when you see an eyebrow, +you're seeing the shaft of the hair. +The root, of course, goes below the skin. +What most people don't realize, however, +is that down at the base of the root, +there's actually a little +cave, a little pocket. +If you were to look at this, +it would look like a little bulb, +a little round area with a bunch +of stuff in it right below the root. +Within that little cave, +there are stem cells. +There are populations of cells +that have the ability to divide. +We call this mitosis. +It's a process by which cells can actually +divide, and take DNA with them, +and then give rise to other cells. +We call those cells that divide and move +out, we call those daughter cells. +We call the cells that give rise to them +progenitor cells, but they are effectively +stem cells that give rise to these +what we call daughter cells. +Those daughter cells then become +the various types of cells +that make up the hair. +When you see a hair, +you're not seeing something +that grows throughout the lifespan. +You're seeing something that's going to be +born down there in that little cave, +then is going to grow. +It's actually going to stack +up on top of itself. +That's because hairs are made +up of a protein called keratin. +There are a bunch of different kinds +of keratin depending on what +kind of hair you're looking at. +But these are little proteins that stack +up on top of one another, +and they're structured in a way +that makes them pretty darn durable. +I mean, it's possible, of course, +to pull a hair out. +But if you've ever tried to tear a hair, +in particular, +thick hair like one from the face or even +one off the top of your head, +it's actually a pretty +tensile strong little thing. +That's because keratins stack up on top +of one another and bind to one +another with a really strong bond. +What you end up with is a bunch +of proteins stacked up on top of one +another, and that's the actual hair. +We've got the hair shaft, the hair root, +and then we've got the stem cells down +there in that pocket that give rise +to the various cells +that make up the actual hair. +We also have down there in that little +cave, which, by the way, +is actually called the hair bulb, +if you really want to know the technical +name because it's shaped like a bulb. +We have not just stem cells, +but we have cells that give rise +to the pigment of the hair +that create what's called melanin. +Now, some people have very blond hair, +very light hair, +some people have darker hair. +But everybody, unless they have what's +called the albino mutation, +where the hairs are truly white, +they lack all melanin, +and it's a pretty rare condition, +although it does happen, +most people have some degree of melanin +in their hairs because there are little +pockets of melanin-producing cells. +Melanin is just a protein that essentially +gets injected into the keratin, into +the hair, and gives it its darker color. +Now, there are a couple other components +about the hair that you need to know +about, especially if you're interested +in reversing hair loss or +reversing graying of hair. +One of those components is a little gland. +Next to every hair root +within the dermal layer of the skin, +so this is below the epidermis, +there is a gland called the sebaceous +gland, and the sebaceous gland makes oily +stuff, and the oily stuff is called sebum. +I know the name evokes something gross, +but sebum is actually really +cool and really important. +The sebum gets injected, or seeps rather, +into the area right around the hair +as the hair starts to approach the surface +where it goes from essentially +root to shaft. +The sebum does two things. +First of all, it forms a little bit +of a seal right at the place +where the hair exits the skin. +And that seal is very important, +actually, for waterproofing of your skin. +So we don't often think of ourselves as +waterproof because we are so accustomed +to water just landing on our +skin and and rolling off. +But that's because of some +of the oily properties of our skin. +Now, it's also true that our skin is +pretty densely packed with cells. +But in the absence of sebum, +we would not be as waterproof as we are. +Now as I mentioned, sebum has +two important properties. +The other important property of sebum is +that it actually is a strong +antibacterial and antimicrobial. +Most people don't realize this, +the oils of your skin provide a lot +of immune boundary, +so that things don't get into the hair +root or the region around +it and infect our skin. +So sebum, while the name is sort +of unattractive, to be honest, +is actually performing some essential +roles both for waterproofing and for our +immune system function, protecting +us from various kinds of infection. +We're going to return to sebum later. +As it turns out, +sebum is also very important as it relates +to psoriasis and as it relates to some +of the fungal components +that can cause hair loss. +So I'm just going to file that away. +There's another important component +of the region around hairs, +which is the arrector pili muscle. +The arrector pili muscle is a muscle +that lies diagonally between that bulb +portion of the hair or a little bit above +it, and goes up to the +surface of the skin. +The arrector pili muscle +is a muscle that contracts when we +get cold or when we get scared. +So if you've ever had goosebumps, +that's because the arrector pili muscle +contracts pulling the skin at the surface +down around the little hair follicles, +or at least where the hairs +meet the surface of the skin. +And so those little bumps are actually +where little micro hairs reside. +And the dimples between them are +the dimples that occur when this +arrector pili muscle pulls down. +Now, why would this muscle exist? +It has a couple of important functions. +One of the functions is that when it +pulls down, it causes, as the name +suggests, the hairs to stand up. +Maybe not perfectly vertical, +but when you hear, oh, I was so +frightened, my hair stood up on end. +And that's because +the hair has become erect. +They stand up. +Now, why would this +happen when we get cold? +It happens because when the hairs stand +up, air can be trapped between those +hairs and can actually warm our body. +This is not so much the case if you +have very light hair on your skin. +If you're a very hairy person, +this is going to be a more robust +aspect of your physiology. +And yes, this is why dogs like Huskies can +go out in the snow and still remain warm. +When they get cold, +their hairs actually stand up a bit on end +because of the contraction of these +arrector pili muscle +trapping air in there. +And then their body warms the hair +trapped beneath the hair. +And it's like they've got a blanket +on made by the interface between the hair, +the air, and their skin. +So just to recap all the components +of hair and the different things around it +that are going to be relevant +for understanding how +to replace hair that's lost. +We have the hair itself, +which has the shaft that sticks out over +the skin, goes a little bit into the skin, +but basically sticks out over the skin. +We have the root portion +which goes down into the skin. +It goes through the epidermis +and into the dermis. +Then we have this bulb like +region down at the bottom. +Down at the bottom of that bulb, +we have stem cells that actually give rise +to the actual hair, and we have +pigmented cells that pigment that hair. +In addition, and this is very important, +there are capillaries that go +into that bulb region down at the bottom +of the hair and that can serve and support +the stem cells, the melanin producing +cells, which are called melanocytes. +So the melanin producing cells in the stem +cells get a lot of blood flow that allows +them to keep providing new hair or +the proteins that make up hair +and the pigment that goes into those hairs +and those little capillaries deliver not +just nutrients and things of that sort, +but they also deliver oxygen because it +turns out that the whole process +of growing more hair is +a very active process. +Now, as soon as you hear oxygen and you +hear that the growth is an active process, +that should cue you to why so many +of the stories around how to keep your +hair and regrow hair involve statements +like don't wear a hat, +it'll make your hair fall out. +Or if you want your hair to grow back, +don't wear hats or massage your +scalp or increase blood flow. +Or why some people will suggest +that people take peppermint oil, +for instance, +or menthol type oils of different +kinds and massage them into the scalp. +Things that make the scalp tingle. +Or there will be light +therapies designed to what? +To increase blood flow to the scalp. +The whole rationale there is that you're +trying to increase blood flow to the stem +cell and the melanocytes populations +that support the hairs +and that actually create the hairs. +Now, whether or not those are approaches +work we'll touch on a little bit later. +I'll just give you a little bit of a hint +right now, which is that while no single +one of those approaches that I described +is known to regrow hair in a very robust +way because of the requirement for oxygen +and nutrients and because it's such +an active process for the stem cells +and melanocytes to grow and darken +the hairs that grow out of your skin. +It is true that manipulations or +treatments that increase blood flow +to those regions can at least slow +the loss of hair or can even extend +the duration over which +hairs continue to grow. +So if you've heard things like don't wear +a hat, if you want to maintain your hair. +Or massage your scalp, +if you want your hair to grow faster. +In some sense that's true, +but none of those manipulations on their +own is going to robustly enhance +the rate of of your hair growth. +Those things are designed to be done +in conjunction with some other treatments +that have been shown in many, +many clinical studies to increase +the rate and duration of hair growth. +So now you have in mind a picture +of what's happening at the level +of individual hairs. +And if you're anything like me, +you're probably thinking, Wow, +there's a lot going on down there +just below the surface of the skin. +And indeed there is. +But really the things to think about are +that stem cell population that actually +give rise to the hair proteins so +that actually create the hair. +The melanocytes that darken that hair, +that give it pigment. +That sebaceous gland and the oil sebum +that provides some important antimicrobial +and other properties +to that general region. +And that arrector pili muscle, +that arrector pili muscle, +as I mentioned earlier, +is important for creating goosebumps +and it's important for keeping +Huskies warm in cold environments. +But it's doing some other really important +things as well, and we'll talk about +those as time goes on in this episode. +Right now, what I want to do is just talk +for a moment about how hairs actually +grow and why they grow the way they do. +This is extremely important toward +understanding hair replacement +and slowing hair loss. +There are three basic +phases of growth of a hair. +The first phase is the phase +in which the stem cells down in that bulb +give rise to the cells that make up +the proteins of the hair, +so the actual growth of the hair. +And keep in mind that the hair is +actually growing from the bottom up. +Now, you might think, of course, +it's growing from the bottom. +Everyone knows that. +But a lot of people think that the hair +starts growing right +at the surface of the skin. +That's not the way it works. +The hair is actually growing from deep +within the root and stacking up and then +eventually extends out +across the top of the skin. +That growth phase is +called the anagen phase. +A-N-A-G-E-N. +And this for some people will ring a bell +because if you've ever been interested +in weightlifting or even if you're +an endurance runner, +you'll hear about things that are anabolic +that promote growth, so Anna of Growth. +Or catabolic that promote breakdown. +So the first phase of hair growth is +called the anagen phase, +and it's a period of varying duration +depending on which hair +in the body we're talking about. +So the anagen or the growth phase +for hairs on the head, as I mentioned +earlier, is anywhere from 2 to 8 years. +For most people, it's going +to be about six years. +What this means is that if we were to just +not cut our hair, just let our hair grow +for 2 to 8 years, +that hair would eventually grow +to a length that it was at its +maximum and then would stop growing. +So we can say that the anagen phase +of hairs on the scalp is 2 to 8 years. +The the duration of the growth phase. +Contrast that, for instance, +with the duration of the anagen +phase for hairs of the eyebrows. +The hairs of the eyebrows grow +about 4.2mm per month. +Believe it or not, people +have measured this thing. +Now that's an average. +So some people are going to have eyebrows +that grow much longer per month. +I'm somebody who, for instance, +has mostly the same length eyebrow hairs, +but every once in a while I get one +of those eyebrow hairs that really seems +to be heading off my head, +like really wants out of there. +And so it's much longer than the rest. +What does that mean? +Does it mean that it grew faster? +Maybe. +But chances are the stem cell population +in that particular eyebrow follicle +for that one eyebrow hair +is longer than it is for the others. +This is really important. +I'm trying to illustrate two +principles at once here. +The first principle is that different +hairs on your body, +including the hairs on your scalp, have +a growth phase of different duration. +This is why the hairs on your head can +grow very, very long because they have +a very long anagen or growth phase, +and the hairs on your eyebrows will only +grow for a few months before they +actually fall out and then have +to undergo replication of the stem cells +to give you new eyebrow hair to then grow. +What's important here is not just +that there are differences in the duration +of the growth phase, +but rather that the rate of hair growth +is not something that tends to differ +within a given body region. +You'll hear people say, "Oh, +my hair grows really, +really fast." Other people will say, "Oh, +my hair grows really, really slowly.' +That is probably not the case. +Well, there could be slight +differences in the rate of growth. +That is the addition of more keratin +to the actual hairs, +so creation of more hair more quickly. +Almost certainly what's happening is +that the duration of the anagen phase +in some people is just much longer +than it is in other people. +We don't realize this, +and we tend to think more in terms of how +fast hair grows, +because if you were to just look +at somebody's hair, you'd say, "Oh, +they're all more or less the same length." +I mean, some people's bangs are shorter +than the back because they cut them. +But if they were to just grow their hair, +you'd say, "Oh, it's all more or less +the same length." But if we were to zoom +in with a microscope, +we would see that there are a lot +of hairs down there in between the other +hairs that are very, +very short or even tiny, tiny, tiny. +Those are coming in as the other ones +are finishing their anagen phase. +That's the anagen or growth phase. +After the anagen phase +comes the catagen phase. +Again, this resembles the word +catabolic or the breakdown phase. +During the catagen phase, +the hair is actually receding not +from the top down to the skin surface and +then into the root, but the other way. +It's actually receding from that bulb +region up toward the surface. +That catagen phase is going to also be +of different duration depending +on which area of the body you're in. +It will vary a little bit depending on +who you are, meaning +from person to person. +We'll talk about the influences on the +anagen and catagen phase in a moment. +Why is it important that it actually +recedes from the inside out? +Well, that's important because as it does +that, there's actually a change +in that bulb region down below, +because normally, there's an interface, +there's a conversation that's occurring +between the stem cell population, +the melanocytes, and the hair itself, +and they support each other. +Remember, there's blood vessels going +into that area or rather capillaries +that are feeding that area as well. +After the catagen phase comes +the telogen phase, which means rest. +The telogen phase is a period in which no +new hair proteins are being +added by those stem cells. +During that telogen phase, +that bulb down there at the bottom, +instead of being nice and oval and really +having a lot of space in it with all these +different things like stem cells, +starts to pinch off +from the little tube that comes down +from the surface of the skin +that normally would have a hair in it. +It starts to pinch off. +At some point, many hair follicles pinch +off that bulb region, +and it recedes and dies. +When it recedes and dies, +the stem cell population +and the melanocytes go with it. +In other words, +there is no longer a population of stem +cells to give rise to more hair +after that telogen phase. +There's no longer melanocytes to pigment +the hair, and in fact, +the hair isn't there anymore, +so there's no hair even to pigment, +after that telogen phase, unless +it's a hair of a particular type such as +the hair on your scalp, +which can then reenter the cell cycle, +and get back into an anagen phase +and regrow more hair from stem cells. +There are three critical stages +of the life cycle of a hair that are +relevant to today's conversation. +There's the anagen phase during +which the hair grows, +there's the catagen phase during which the +hair actually starts to recede and die. +The protein is actually +disappearing from the bottom up. +Then we have the telogen phase, +which is the phase in which the stem cell +population is what's called a semi +quiescent, semiquiet, or completely +quiescent, where it's not active at all. +Those three phases make up the life cycle +of a hair, keeping in mind that for some +hairs, they can reenter the life cycle +and go back into the anagen phase, +if there's stem cells there, +and if there is oxygen there, +and if there is sufficient blood support, +and—and this is a very important and— if +there are the appropriate hormonal +signals to support growth, +and there is a reduction or an absence +in the hormone signals that actually +trigger that telogen phase. +I make this point now because much +of the rest of today's discussion is +going to focus on why particular hormones +such as dihydrotestosterone cause hair +loss and why inhibiting things like +dihydrotestosterone can support +the preservation of hair that you have +and the regrowth of hair. +To make a long story very short, +and then we'll get into some additional +details that are relevant, +and that I hope you'll stick around +to listen to, dihydrotestosterone, +which is a derivative of testosterone, +causes changes in that bulb region +where the stem cells reside. +It shortens or halt the anagen phase +of hair growth, and it extends and +promotes the catagen and telogen phase. +When we hear that, "Oh +dihydrotestosterone makes your hair fall +out, or estrogen makes your hair grow," +there are real chemical people, +or we should say biochemical +legitimate reasons as to why that is. +But it all comes back to this three +phases of hair growth: the anagen growth +phase, the catagen, +catabolic or hair loss phase, +and the telogen phase, +which is a rest period in which the hairs +can either come back, +if it reenters the anagen phase +or maybe it's over for good. +Hormones are the accelerator and the +brake on each one of those phases. +I'd like to take a quick break +and acknowledge one of our +sponsors, Athletic Greens. +Athletic Greens, now called AG1, +is a vitamin mineral probiotic drink +that covers all of your +foundational nutritional needs. +I've been taking Athletic Greens since +2012, so I'm delighted that they're +sponsoring the podcast. +The reason I started taking +Athletic Greens and the reason I still +take Athletic Greens once or usually +twice a day is that it gets me the +probiotics that I need for gut health. +Our gut is very important. +It's populated by gut microbiota +that communicate with the brain, +the immune system, +and basically all the biological systems +of our body to strongly impact our +immediate and long-term health. +Those probiotics and Athletic Greens are +optimal and vital for macrobiotic health. +In addition, Athletic Greens contains +a number of adaptogens, vitamins, +and minerals that make sure that all +of my foundational nutritional +needs are met, and it tastes great. +If you'd like to try Athletic Greens, +you can go to AthleticGreens .com/ +huberman, and they'll give you five free +travel packs that make it really easy +to mix up Athletic Greens while you're +on the road in the car, on the plane, +et cetera, and they'll give you +a year's supply of vitamin D3 K2. +Again, +that's athleticgreens.com/huberman +to get the five free travel packs +and the year supply of vitamin D3 K2. +Now you have in mind the anatomy +of the hair and the area from which it +grows, and the stem cells, et cetera. +The fact that there's capillary +innervation delivering oxygen and blood +flow to the stem cells that give rise +to the hair, and that there are these +three critical phases of hair growth: +anagen, catagen, and telogen. +Now, let's talk about the accelerators +on hair growth and the +brakes on hair growth. +There are many accelerators on hair +growth, but the first one that I really +want to underscore is blood flow itself, +which equates to the delivery +of nutrients and oxygen. +This is very important, +and it explains a lot of the treatments +for halting and reversing hair loss. +For instance, one of the longest standing +treatments for halting and reversing +hair loss is so-called minoxidil. +Minoxidil, sometimes also referred +to by the brand name ROGAINE, +was actually a drug that was +developed to treat hypertension. +This is a cardiac drug that lowers blood +pressure, and it does +that by causing vasodilation. +It allows more blood flow, +not just to the hairs on your scalp, +but to hairs everywhere on your body. +Indeed, most people don't realize this, +but minoxidil won't just slow the loss +of hair from your scalp, +it is also effective at slowing +the loss of hair elsewhere in your body. +How does it do that? +Well, you now know one +of the major ways it does that. +It does that by extending the anagen +phase, so it basically makes that phase +a bit longer, and does it make it +much longer, which is why for most people +who are losing their hair quickly +or who have already lost their hair, +minoxidil alone is not going +to be a sufficient treatment. +However, minoxidil has been shown to be +effective at slowing rates of hair loss +in people that are starting +to experience some hair loss. +I'll get into dosages and things +of that sort a little bit later, +but right now I just want to really focus +on the logic of why people would take +this drug, +which is lowering hypertension +at all as it relates to hair loss. +That might seem like crazy until you +understand the anatomy and the growth +of hairs, which you now do. +That's what minoxidil is doing. +It's creating more blood flow +to the hairs, which because minoxidil +does have this positive effect, +at least most people would like to slow +their rates of hair loss on their scalp +anyway, it tells you that blood flow +and delivery of oxygen and other +nutrients from the blood is pretty +critical, if not very critical, for the +support of the hair growth cycle itself. +Now, again, we haven't talked at all about +the sorts of chemicals or the signals +within the body, such as hormones +that actually direct the growth of hairs. +Here, we're just talking about +a mechanical change, +allow more blood flow to the region, +and thereby extend the anagen phase, which +is exactly what happens with minoxidil. +Now, minoxidil does have other effects, +and this is why dosing of minoxidil +becomes a little bit complicated and can +be a little bit tricky to troubleshoot. +It can greatly lower blood pressure +or lower blood pressure just a little bit, +depending on how sensitive somebody +is to that particular drug. +Oftentimes physicians will start people +on Minoxidil dosages that are very low. +Ideally, that would be the case and then +ratchet it up in order to figure out +where the minimal effective dose or the +critical threshold is beyond which they +start experiencing some pretty +uncomfortable side effects, +such as swelling of the ankles +or headaches or dizziness. +These things can happen with the use +of Rogaine, aka Minoxidil. +Now, Minoxidil has also been associated +with increases in the hormone prolactin. +Prolactin is a hormone that's +released from the pituitary. +It is a hormone that acts also as a bit +of a neurotransmitter, like many hormones, +and it tends to be antagonistic +or an opposite to dopamine. +Dopamine is a neurochemical. +It's actually a neuromodulator, +meaning it modulates the activity of a +bunch of neural circuits in the brain. +It also controls the release +of various hormones in the body. +Dopamine is almost always associated with +states of motivation, pursuit, and drive. +It has a little bit of a feel- good +element to it, +which is why a lot of people think +dopamine is associated +with reward and pleasure. +But it's really about energy, +motivation, and drive. +Dopamine and prolactin are, +as I mentioned before, +antagonistic to one another. +They're in sort of a push-pull. +People who take Minoxidil, +especially if they're very sensitive to it +or they take dosages that are too high, +will experience increases in prolactin +that in turn can cause things like +reductions in libido, +reductions in overall feelings +of well-being, apathy, +and in some cases where the elevations +in prolactin are more extreme, +they can experience, for instance, +increase in male breast tissue +gynecomastia or even small bits +of milk letdown, things of that sort. +In women who take Minoxidil, +the side effects are much like +the ones in experienced in men. +So there can be swelling, +edema of the tissues +because if you get too much vasodilation +and too, too much lowering of blood +pressure, that's not good. +Headaches, dizziness and so on. +Dosing of Minoxidil is really important. +If somebody is going to use Minoxidil +in order to try and slow or reverse hair +loss, again, it mainly is going to be used +to slow rates of hair loss, +not to actually reverse hair loss. +The really key thing is +to get that dosage right. +The ranges of Minoxidil that you'll see +suggested and that people +use out there are vast. +I should also mention that there are two +major routes by which people get +Minoxidil to the hair follicle. +One is to take it systemically as a pill +where it goes into the +general circulation. +The other is to take it +topically as a cream. +There are prescription and non- +prescription forms of Minoxidil +just to further complicate things. +But the ranges of oral Minoxidil +that you'll see out there and that people +take range anywhere from 0.25 milligrams +all the way up to five milligrams per day. +That's an enormous range. +It's like a 20-fold range. +The topical Minoxidil is also +found in various concentrations. +The typical concentration is going to be +a 5% concentration that people +will use once per day. +Topical treatment with Minoxidil at 5% +concentration is thought to just stay +at the scalp, but we now know that it +can go systemically, it can get +into the general bloodstream. +Why that is should make complete sense +to you because when you put something +on your scalp, I've already told you +that these little pits, +these little tubes that go down to those +bulb regions below the skin that have +direct access to the blood supply. +When you massage something into your +scalp, it not only has the opportunity +to get into your general circulation, +it often does, +especially if it's something that's very +water-soluble and that way can get +into the capillaries and into the general +bloodstream, although topical treatments +of which we're going to discuss, +a number of them today don't tend to get +into the general circulation as robustly +as taking something +by way of pill or capsule. +Minoxidil works by way of increasing blood +flow to the stem cell +niche below the hair. +The dosage ranges of the oral Minoxidil +are tremendous, 0.25 milligrams, all the +way up to five milligrams once per day. +The dosage range of the topical solutions +tends to be a little bit more confined. +Typically, it's a 5% solution and it's +recommended that people +use it one time daily, maybe twice daily. +It's also important, by the way, +if you're going to take this route, +that you actually leave that solution +on the scalp for 3-5 minutes. +This is important and should make +complete sense as to why it's important. +You can't just rub the stuff into your +head and then rinse it off +and expect it to be absorbed. +It actually needs to seep down into those +hair follicles and access the niche. +How do people arrive at the +correct dosage for Minoxidil? +Well, for better or for worse, really, +in some cases, +it's accomplished by finding out that you +have an unwanted side effect, like +dizziness or swelling of your ankles or +edema or I would hope this wouldn't be +the case, but something that suggests +there's hyperprolactinemia. +You could get a blood test to measure +your prolactin or you perhaps notice +a drop in libido or some lethargy. +These sorts of things that are common +to reduce levels of dopamine, +increased levels of prolactin. +I would hope that if people are working +with a physician or if they're not +in taking Minoxidil, that they would +start with the lowest possible dose. +For oral Minoxidil, +that would be 0.25 milligrams and then +increase it as needed rather than jumping +in right at five milligrams because some +of those side effects, +in particular the fluid retention +and the hyper prolactinemia +can be pretty uncomfortable and can +disrupt a lot of aspects of life +that most all of us consider desirable. +We're really focusing right now +on treatments that relate +to the critical requirement for hair stem +cells to receive blood flow in order +to receive oxygen and nutrients, +to get the hair to grow. +That's really what Minoxidil is about. +It's also what all of those anecdotes +you hear are all about, like +massaging the scalp or putting +red light on the scalp. +Although red light might do some other +things, in general, +heating or lighting of the scalp or +massaging of the scalp is really designed +to increase blood flow to the scalp. +Now, the reason Minoxidil works at all is +because it is going to increase blood +flow around the clock, +and that's because people are taking it +topically and it's seeping +into the general circulation, +or at least it stings somewhat +restricted to the hair cell niche. +Or they're taking it orally and it makes +it to that hair cell niche +below the follicle. +When we massage our scalp, however, +that's a transient thing, +like I massage my scalp right now, +I'm no doubt +increasing blood flow to certain areas +and probably decreasing blood flow +to the areas I'm pushing down on. +But it's all temporary. +I don't know many people that can massage +their scalp enough during the day or long +enough during the day rather that it +would sufficiently increase blood flow. +With that said, +it is clear that increasing blood flow +to the scalp by way of reducing +hypertension, +which is effectively accomplished +by broadening by expanding the blood +vessels and capillaries, +is an effective way to at least +hold on to the hair that you have. +Is it going to completely halt hair loss +if you have a strong genetic +bias towards hair loss? +No. +Is it going to reverse hair loss? +Very unlikely that it will. +But it can slow hair loss or even +maintain the hair that you have. +If we were to take a step back and ask +ourselves what other sorts of drug +treatments are out there besides +Minoxidil, that increase blood flow +and that might increase the rates of hair +growth or more likely increase +maintenance of hair that one already has +by increasing blood flow to the niche. +Nowadays, there are more and more doctors +who are familiar with this +requirement for blood flow. +Understand the mechanisms +by which Minoxidil works and understand +the vast desire out there for people +to hold on to the hair they have +and regrow hair and they are prescribing +things like low-dose tadalafil, +so 2.5 milligram to five +milligram tadalafil. +Tadalafil was initially discovered +as a drug to treat prostate health. +It was a drug that we now know can +increase blood flow to the prostate +and thereby offset some of the issues +associated with an aging prostate. +Higher doses of tadalafil +sometimes also referred to by its brand +name, which is Cialis, +are used to treat erectile dysfunction, +but at the dosages that are used +to increase blood flow to the prostate +and that now a number of doctors are using +to increase blood flow not just +to the prostate but to all regions +of the body, including the scalp, +such as 2.5-5 milligram tadalafil. +This is something that I think deserves +attention because it falls under +the umbrella of increasing blood flow +to the hair stem cell niche +in order to maintain hair. +It is not something that most doctors +are going to be familiar with as the way +to reverse hair loss +because it won't do that. +But the use of low-dose tadalafil +to slow rates of hair loss is very much +in a logical mechanistic sense, +exactly the same as the logic of using +Minoxidil to slow rates of hair loss. +It's all about increasing blood flow +to support the stem cell niche +below the hair follicle. +The critical requirement for blood flow, +oxygen and nutrients to the stem cell +niche is also why you hear a lot nowadays +about the use of PRP, +platelet-rich plasma for trying to offset +hair loss or even reverse hair loss. +We're going to do an entire +episode about PRP. +It is pretty controversial in certain +circles and well- accepted +in other circles. +A couple of key things +to understand about PRP. +First of all, +it is being used in multiple tissues for +different purposes in different clinics. +For instance, +board-certified physicians +in the United States, Canada, +and Europe are doing PRP injections +into ovaries to try and expand the number +of healthy follicles and eggs so +that people can conceive later in life or +even earlier in life if they +don't have many follicles. +People are getting PRP injections +into their joints in order +to try and support joint health. +People are getting PRP injections into +just about every tissue you can think of. +However, PRP, despite what you may +have heard, is not stem cells. +Somebody tells you they're injecting stem +cells, they're either outside the US, +Canada, or Northern Europe, +or they're injecting something else. +So you want to really look into that. +The safety issues there are subject +totally deserving of an entire episode. +I'm not necessarily opposed to the future +of stem cells as a treatment, +but keep in mind that stem cells are +cells that can give rise to lots of other +cell types, and they are cells +that divide and replicate. +There's a name for that when it happens +in the adult body when +you don't want that. +That's called cancer. +Tumors are over-production of cells +from stem cells when those stem cells +ordinarily should be quiescent. +Keep in mind the difference +between stem cells and PRP. +PRP, platelet-rich plasma, +again, is legal in the US and many other +places because it involves drawing +somebody's blood, +spinning it down at a particular speed, +which separates out different +components within the blood. +Then taking the platelets and re- +injecting those in a solution +back into the person's body. +Platelet-rich plasma or PRP is platelet +enriched plasma from that person. +But the basis of PRP is really +to encourage nutrient delivery +to a particular region in the body using +somebody's own platelets, +because those platelets are +enriched for various nutrients. +People are getting PRP +injections into their scalp. +Those are not stem cell injections. +Those are PRP injections into the scalp +with some moderate success. +These are very expensive treatments. +They tend to be transiently successful. +I'm sure there are people out there +who are going to say, +"PRP worked fabulously well +for me." That might be the case. +I'm not going to dispute that. +And I'm happy for you. +Although there are not sufficient +clinical data to suggest PRP as +a treatment right now, +especially given the cost, many thousands +of dollars, many, many treatments. +It's also the case that the PRP +injections, when they work, might work +for reasons independent of the platelets. +What do I mean by that? +Well, soon, we're going to talk about +a different type of treatment, +which is a mechanical manipulation +of the hair follicle, typically, +on the scalp, because that's typically +where people want to regrow hair. +I don't know many people who are trying +to maintain or accelerate or regrow +their back hair, for instance. +They might be out there, +but I don't think there are a lot of them +or their leg hair, for that matter. +Almost always, +it's going to be scalp hair. +And one way that people are doing +that is through mechanical stimulation +of the hair follicle and the stem cell +niche using what's called micro-needling. +Micro-needling, as the name suggests, +is taking a bunch of little +needles either in a little stamp. +A little square or nowadays, +typically, it's a roller. +It looks like a paint roller, +except it's got tons of little +needles in rows all over that roller. +Those needles range in length from half +a millimeter to 2.5 millimeters. +Millimeters and one rolls +that over the scalp. +If you're thinking, ouch, +that probably hurts. +Indeed, it can hurt a little bit or a lot, +depending on the thickness +and the length of those needles. +Micro-needling has been +shown to do two things. +It has been shown to reactivate semi- +quiescent populations of stem cells +that are in that telogen phase, +putting them back in antigen phase +and thereby stimulate more hair growth. +It has also, and this is I think, +the best use of micro-needling. +It has also been shown to be a very +effective augment for some of the hormone- +based hair regrowth tools +and pharmacology that we're going +to talk about in a few minutes. +Micro-needling and PRP have something +very critical in common, +which is the needle, +the actual injection into the skin. +For those of you that are hearing this +and thinking, +why would disrupting the skin with needles +actually, support hair growth or regrowth, +wouldn't that just damage the follicle? +Well, this gets into some of the, I think, +interesting, if not fascinating aspects +of our biology, +which is that all of the cells in our body +really can respond to both +chemical and mechanical cues. +When we hear needle injected into skin, +we think, oh, that must just be damaging +everything, causing all +sorts of inflammation. +But it turns out that low levels +of inflammation caused by things like +micro-needling or PRP injections or even +the introduction of any kind of fluid. +For instance, saline fluid injected +into a region can cause changes +in the cells in that region, causing, +for instance, stem cell populations +that were waning to reactivate again, +causing telogen phase follicles that have +melanocytes and stem cells that are dying +off but not completely gone +to reenter the cell cycle. +Micro-needling procedures, PRP injections, +things like Minoxidil, +they all kind of center around this same +general theme of increasing blood flow, +increasing oxygen, delivery of nutrients, +or in the case of micro-needling, +increasing inflammation just enough +at that local site that certain cascades +of biological function that relate +to proliferation of stem cells or +maintenance of stem cell +populations are kicked off. +It's sort of like reminding the cells +in that area that they need to stay alive +in order to replenish whatever is lost. +Sometimes a wound can +actually induce some healing. +Although I do want to point out +that the micro part of micro-needling is +absolutely key and this should be +obvious to you when +you think about scars. +I don't know about you, +but I've never seen a scar with hair +growing out of it, or if there was, +it was probably like one hair. +But if you've ever seen a scar, +someone had their appendix out or if +someone had a brain surgery, +you see that scar because there is +no hair growing out of it. +So the micro portion of micro-needling +is extremely important. +We are not talking about causing +significant damage to a tissue in order +to activate that stem cell population. +We're talking about causing microdamage +and micro levels of inflammation +to stimulate growth. +For those of you that are interested +in using micro-needling or micro-needling +in combination with chemical treatments +like Minoxidil or some of the other +treatments we'll talk +about in a little bit. +Like finasteride and caffeine. +Yes, believe it or not, +caffeine is being used to regrow hair. +Very interesting. +Get into that in a moment. +But if you're interested in using m +icro-needling alone or in combination +with some of these other treatments, +there's a wonderful review that was +just published this last year. +Wonderful, because it's +very comprehensive. +Not so wonderful. +Not to the fault of the authors because +most of the studies out there +on micro-needling are not superb. +There are ways of gauging the strength +of a study mainly relate to their +duration, whether or not they +were control groups et cetera. +But the review itself is excellent +and the title of the review is M +icro-needling and its Use in +Hair Loss Disorders: A Systematic Review. +We will provide a link to this +in the show note captions and this review +did a very good job of highlighting both +the strengths and drawbacks of the various +studies looking at micro-needling. +It also explored the use of micro-needling +in both men and women and of various +ages, and it does appear to be the case +that micro-needling shows some positive +benefit in both men and women, +regardless of age, +especially when used in combination +with the various other treatments +that we're talking about. +I was also able to glean from this review +and some of the papers described within it +that needle lengths of about one +millimeter to 2.5 millimeters seem to be +more effective than +shorter needle lengths. +So if you're scared of the needles +and the needle lengths, +keep in mind that done properly, +micro-needling shouldn't be too painful. +Some people experience a little bit more +pain than others, but it's not +considered a very painful procedure. +It is, however, a procedure that can cause +some bleeding of the scalp, +and that bleeding of the scalp can be +very apparent, +especially if it's in the front +of the head as opposed to in the top +of the head and hidden by some hair or if +you're already +quite bald in a given region. +Keep that in mind. +I suppose one could wear a hat or a wig +or something of that sort if they +were really self-conscious about it. +But the micro-needling itself is causing +a physical disruption to the scalp, +some degree of bleeding, inflammation. +And again, all of that is part +of the process by which micro-needling +can actually improve hair growth. +Of course, there's healing that occurs +of the bleeding and the +damage to the follicle. +This is a transient thing, +but understanding the cosmetic +implications in the short term as well as +in the long-term is +certainly worth knowing. +One thing that's very clear is +that the combination of micro-needling +and Minoxidil treatment together is far +more effective than either +of those treatments alone. +In addition, +the combination of micro-needling +and Minoxidil has been shown to be +effective in recovering +what are called dead zones. +These are regions of the scalp that are +either completely bald or mostly bald, +for which there is essentially +no stem cell population there. +The combination of Minoxidil plus +micro-needling is somehow able to recover +those stem cell populations and allow +new hair to grow, +although the growth of that hair +in those dead zone regions can take +a very long time, 30 to even 50 weeks. +Neither Minoxidil treatment alone nor +micro-needling alone has been shown to be +effective in recovering these so-called +dead zones when those +treatments are done separately. +This, I would say, +is a strong reason to consider combining +micro-needling and Minoxidil as opposed +to just doing Minoxidil +or just micro-needling. +I should also mention that Minoxidil +treatment, if you pursue it, +is likely something that you are going +to have to do for the rest of your life. +If you want to hold on to the hair growth +that you obtain with Minoxidil or if you +want to maintain the hair that you are +already maintaining with Minoxidil. +Some people have been successful +in taking Minoxidil, maintaining some hair +growth or even stimulating some hair +growth and then coming off Minoxidil. +But most everyone who goes on Minoxidil +has to stay on Minoxidil because when +they cease taking Minoxidil, +even if they're doing other treatments, +they lose the hair that they gained +with Minoxidil, so that is +an important consideration. +The decision to go on Minoxidil is likely +a decision to be on Minoxidil +for the rest of your life. +I'd like to just take a brief break +and thank one of our +sponsors, which is LMNT. +LMNT is an electrolyte drink that has +everything you need and nothing you don't. +That means plenty of salt, sodium, +magnesium, and potassium, the so-called +electrolytes, and no sugar. +Salt, magnesium, +and potassium are critical to the function +of all the cells in your body, +in particular to the function of your +nerve cells, also called neurons. +We now know that even slight reductions +in electrolyte concentrations or +dehydration of the body can lead +to deficits in cognitive +and physical performance. +LMNT contains a science-backed +electrolyte ratio of 1,000 milligrams, +that's one gram, of sodium, +200 milligrams of potassium, +and 60 milligrams of magnesium. +I typically drink LMNT first thing +in the morning when I wake up in order +to hydrate my body and make sure I have +enough electrolytes, +and while I do any kind of physical +training and after physical training as +well, especially if I have been sweating +a lot, and certainly I drink LMNT +in my water when I'm in the sauna +and after going in the sauna because +that causes quite a lot of sweating. +If you'd like to try LMNT, +you can go to drinklmnt, +that's drinklmnt.com/huberman. To claim +a free element sample +pack with your purchase. +Again, that's drinklmnt +, drinklmnt.com/huberman. +So, as you're probably starting +to realize, there's a relationship between +mechanical stimulation of the follicle +and blood flow, both of which turn out +to be critical for maintaining hair +and for stimulating hair growth. +Not surprisingly then, an increasingly c +ommon treatment for hair loss is Botox. +Botox is the brand name for what is +otherwise known as botulinum neurotoxin. +What is botulinum neurotoxin? +Botulinum neurotoxin, +sometimes just called botulinum +for short, is a toxin that's a bacterial +toxin that serves to cut the protein +that leads to synaptic vesicle release. +What in the world did I just say? +Well, when your nerve cells communicate +with one another, +they do that by way of electricity, +but the electricity within those nerve +cells, those neurons, +triggers the release of chemicals +from neurons into the synapse, +the little gap between neurons. +The release of those chemicals allows +the next neuron to be chemically active, +or in some cases, it will suppress the +electrical activity of that next neuron. +Botulinum neurotoxin serves to cut +a protein present in neurons so +that neurons cannot release the chemicals +that cause other neurons to be active. +This actually is pretty serious. +If you were to get botulinum neurotoxin +injected into your muscle you would be +paralyzed because the nerves that control +contraction of the muscles would not be +able to control the release +of that chemical onto the muscle, +which makes it contract. +Botulinum neurotoxin is commonly +used in what's called Botox. +Botox is something most people are +familiar with because people get it +injected in and around their wrinkles +because many wrinkles are triggered +by not just loss of tensile strength +in the skin, but rather, +the nerves around the skin +and in the skin are hyper contracted, +which causes wrinkles. +For instance, I have crow's feet. +I like to think that's because I've +laughed a lot and smiled a lot, +and it's probably also because +I've squinted a lot in my lifetime. +I have crow's feet because the nerves +there have pinched the skin on either +side of my eyes and that's given me +little creases there that are +sometimes referred to as crow's feet. +Botox injections can be applied +to the scalp in order +to relieve tension of the scalp. +In hearing that, it should be obvious why +Botox is being used to try +and offset hair loss. +It's decreasing the squinting, +if you will, or the tensile nature +of the scalp skin so that more blood flow +can arrive at that stem +cell follicle area. +Botox treatment to the scalp is +actually becoming pretty common. +There are a couple requirements +with this Botox treatment. +First of all, it has to be done +by somebody who's really skilled. +There are numerous images online +and websites online of so-called Botox +fails, where people have gotten too much +Botox or the injections have been done +too deep or not at the correct locations +on people's face or scalp, and it can +give them droopy scalp or droopy eyes. +All sorts of cosmetic nightmares +can occur with Botox. +The second thing to understand is +that Botox does eventually wear off. +That botulinum neurotoxin +doesn't stick around forever. +Provided it's done correctly +at the correct dosages, +it doesn't actually kill the neurons +that cause that tension of the skin, +so Botox injections have +to be done repeatedly. +The efficacy of Botox for offsetting +hair loss is not clear. +There aren't a lot of large- scale +clinical studies on this just yet, +but it does seem to be at least one +reasonably safe alternative to things +like Minoxidil, although I think if one +were to just want to increase blood flow +to the scalp, things like low- dose +Tadalafil, which doesn't seem to carry any +of the side effects that Minoxidil can +carry, we talked about those side effects +earlier, that would probably +be the better alternative. +Botox is a fairly invasive procedure, +but some people opt for Botox treatment. +In fact, there is a syndrome called +cutis verticis gyrata. +Some of you have probably seen this. +It's more typical in men, +although it does occur in women. +It literally means a lumping of the skin +on the scalp, or gyri of the scalp. +Gyri or gyrus pertains to the Latin +word knee, so it means bump or knee. +Any time you hear the word gyrus +in neuroscience or in biology, +you're talking about a bump. +You'll sometimes see people will have +ridges in the back where it looks as if +the skin was pushed together, kind +of like a Shar-Pei dog, but on the scalp. +People with cutis verticis gyrata almost +always experience pattern hair loss. +Now, part of the reason for that is +cutis verticis gyrata +is also associated with some androgen or +testosterone- related hormone issues +that we'll talk about in a little bit. +But in addition to that, +it has been shown that relieving some +of those gyrata by injections of Botox +to allow those folds to sit flatter, +A, is effective. +It can lead to less of those gyri, +those bumps, and can improve hair growth +in those regions, +even if those people don't take on any +additional treatments +to address the hormone issues. +That's really how people arrived at this +understanding that Botox might be a good +treatment in general for reducing the +squinting of the scalp that can occur +and the resulting hair +loss in those regions. +I'd now like to turn our attention +to the chemical variables that control +the duration of the growth phase of hair, +the duration of that catagen phase, +which is when that hair essentially +recedes from the inside out, +and the quiescent or semi- +quiescent telogen phase. +There are a couple of key chemical players +here that we should all be aware of. +First of all, the growth factor IGF-1, +insulin growth factor 1, +which is produced by the liver, +but that receives stimulation +from the brain and pituitary to be +released, is a strong +regulator of hair growth. +We can think of it as +the accelerator on hair growth. +It does that by extending that anagen, +or growth phase, for longer. +It doesn't necessarily speed up growth, +but it extends it for +a longer period of time. +In addition, cyclic AMP, +which is part of what's called a second +messenger pathway, in fact, +cyclic AMP is a second messenger, +is also a key player in stimulating +growth of the hair follicle. +Now, cyclic AMP does many different things +in many different cell types in the body. +It really acts, as the name suggests, +as a messenger between signals +that arrive at the surface of cells +and transmitting or conveying those +signals to things that happen deep within +the cells, such as the turning +on and off of various genes. +When you hear second messenger, don't +let that confuse you or overwhelm you. +Just understand that the whole process +of getting signals from the outside +of cells into the center of cells +and controlling gene expression, +for instance, +causing a stem cell to continue to give +off daughter cells, or causing a hair cell +to continue growing for longer, +that whole process is a bit like +a bucket brigade of handing off water or +a bucket from one component +to the next, or along a chain. +It's like an assembly line. +I think that's probably +the simplest way to think about it. +For sake of this discussion, +IGF-1 is known to increase the growth +of hair by extending that anagen phase, +as is cyclic AMP. +Those are going to be considered +the accelerators, +at least in this conversation. +The brakes on hair growth are going to be +the things that either shorten +the anagen phase or that extend +the catagen phase or this quiescent phase, +which is the telogen phase. +The two major brakes on hair growth +that we want to think about are PDE, +which is a phosphodiesterase, +anytime you hear -ase it's likely +to be an enzyme, and TGF-beta-2. +This is a particular growth factor that, +somewhat counterintuitively, +doesn't stimulate growth, +it actually stimulates lack of growth, +or shortens growth. +With all of that in mind, +and please do also keep in mind that you +don't need to remember all those specific +terms, just understand that there are +some factors, like insulin growth factor +1, that act as accelerators on growth, +and there are factors +that act as brakes on growth. +We can start to think about why, +for instance, half of all people +by age 50 start to lose their hair. +Well, they start to lose their hair +because of something called androgen- +related alopecia, which, +translated to English, +means testosterone and testosterone- +derivative induced hair loss. +This is true in men and women. +Hearing that, you should probably be +wondering the following thing: +Young men have higher levels +of testosterone than old men, right? +Well, the answer is yes, +although some older men in their 40s, +50s, even 80s, maintain testosterone +levels similar to many men +in their 20s, but most don't. +It's a downward slope +starting at about age 40. +How steep that downward slope is depends. +Women, too, have testosterone. +In fact, women have higher levels +of testosterone than they do estrogen. +That's right. +A healthy woman has higher levels +of testosterone than she does estrogen. +However, women, on average, +have lower testosterone than most men, +so they still have far more estrogen +and far less testosterone than most men, +but the level of testosterone that they +have within their body is higher than +the level of estrogen they have. +Androgens such as testosterone and its +derivatives, such as dihydrotestosterone, +which will be much the topic of what we're +getting into next, +inhibit IGF-1 and cyclic AMP. +Again, androgens such as +dihydrotestosterone inhibit, +prevent the action of IGF-1 and cyclic +AMP, which you just learned a few moments +ago, act to extend the anagen +or growth phase of hair. +Which then raises the question, well, +if young people, both male and female, +have higher levels of testosterone than +they do when they're older, +why would people lose their hair +when they're older and not younger? +The answer lies in the conversion +of testosterone to dihydrotestosterone. +Testosterone most people have heard of. +Dihydrotestosterone, or DHT, +is made from testosterone. +There's an enzyme called 5-alpha +reductase that converts testosterone +into dihydrotestosterone +in both men and women. +Dihydrotestosterone binds +to the androgen receptor at five times +the affinity of testosterone, +so it is the most powerful androgen +in humans, and it is responsible +for a number of things that we all +really want and like, such as +mental vigor, physical vigor, strength, +healing capacity, drive, +libido, and on and on. +DHT itself is not bad. +If we take a step back and we +acknowledge testosterone levels are +higher in males and females at younger +ages as opposed to older, +but as they get older, +there is more 5-alpha reductase activity, +which is converting more +of that testosterone +to dihydrotestosterone +and dihydrotestosterone inhibits hair +growth by reducing IGF-1 and cyclic AMP, +well, then we should all be aboard why it +is that by age 50, about 50% of people +experience pattern hair loss. +That is androgen-dependent alopecia, +but translated to normal +English is pattern hair loss. +In a moment you'll understand why some +people lose their hair from the crown +region in the back of the head, +or back and top of the head, +whereas other people lose their hair +in the front of their head, +in the flanks, +right on either side of the midline, +or maybe in the midline +and front altogether. +That's because different people, +depending on their genetic lineage, +have different patterns of androgen +receptors on their scalp. +The pattern of androgen receptors +that you inherit indeed does +come from your mother's side. +This is what gave rise to the the myth +that if you want to know if you're going +to go bald or not, just look +at your mother's father. +Doesn't quite work that way. +In fact, if you think about the logic, +you should really look at your mother's +mother if you want to know your pattern +of androgen receptors on your scalp. +However, most women don't lose as much +hair from their scalp, +or they have ways of covering up the hair +loss in their scalp because their hair is +just generally longer or they're using +other approaches, so that you never really +get a clear picture of what the androgen- +dependent hair loss was +in your grandmother. +Now, we don't want to go too far down +the genetics rabbit hole because, +as you know, you can't select your +parents anyway, but if you want to know +why, for instance, +I'm losing a bit of hair on either side +of the midline in the front, +it almost certainly has to do +with the fact that I have a higher density +of androgen receptors there, +as opposed to, say, +on the crown of my head where, +for whatever reason, +my hair seems to grow thickest. +Other people lose hair on the crown, +in the back and top, but not in the front, +and some people will lose it all over. +Now you understand why hair loss +occurs in certain regions of the body. +You should also understand +that the androgen receptors on the face +are also what are responsible +for beard growth. +This is where it can get a little bit +tricky, but a lot of things will start +to make sense if you can understand +this and internalize this. +If you have a high density of androgen +receptors on your face, +well then as your DHT levels go up +with age, you will be able to grow +a thicker and thicker beard. +In fact, it is rare to see someone who can +grow a thick beard in their youth, +but not so much as they get older. +In fact, the reverse tends to be true. +The pattern of androgen receptors differs +between the scalp +and the face and the back. +On your back you have androgen receptors +and their DHT stimulates hair growth. +If you know someone who has a very hairy +back, or if you have a very hairy back, +that means you have a high density +of androgen receptors on your back. +If you have a beard and that beard is +thick, well then you have a high density +of androgen receptors on your face. +However, a high density of androgen +receptors anywhere on your scalp is going +to predispose those regions to androgen- +dependent alopecia, or hair loss in those +particular regions, +which is going to allow us to understand +why all of the rest of the treatments +for halting hair loss +and for stimulating hair growth, +almost all of those center on inhibiting +either DHT directly, or 5-alpha reductase, +the conversion of testosterone to DHT. +Now I'd like to discuss the ways that one +can chemically adjust certain things +within the hair growth pathway, +things like IGF-1, PDE, TGF beta, etc, +in order to stimulate hair +growth or halt hair loss. +The first thing on this list is actually +going to be pretty surprising to a number +of you, and that's caffeine. +We all think of caffeine as +a stimulant that we drink. +I certainly drink coffee in Yerba Mate, +the occasional energy drink, +things of that sort. +Caffeine does many things besides +stimulate our central nervous system +and make us feel less sleepy, however. +One of the things that caffeine does is +it is a fairly potent PDE inhibitor. +By being a potent PDE inhibitor, +it indirectly stimulates IGF-1. +Why? +Well, because PDE can suppress IGF-1, +and by ingesting caffeine, +or by applying topical caffeine ointment +or cream to the scalp, +you can suppress PDE sufficiently enough +to increase IGF-1 and increase some hair +growth, or at least maintain +hair growth in that region. +This may come as a shock, +it might seem a little bit esoteric +or even outside the margins of typical +treatments, but head to head, +topical caffeine application can be as +effective as Minoxidil application +without actually lowering things like +blood pressure and potentially increasing +prolactin and some of the other negative, +let's call them negative because +they are, side effects of Minoxidil. +Caffeine ointments, and caffeine present +in various hair treatments +and creams, etc, is starting to become +a more prominent theme out there. +I will include a reference to caffeine +and its uses for offsetting hair loss. +Keep in mind that topical caffeine +ointments shouldn't necessarily be applied +every single day, so this is the sort of +thing you might do three times a week. +The concentration of caffeine in +different ointments varies tremendously. +Most of the studies of caffeine +on the stem cell niches that control hair +growth and extension of the anagen phase +of hair growth have been +performed in vitro in a dish. +Although there are some clinical studies +exploring this, they are not nearly as +extensive in number or duration as +the studies of Minoxidil because this +approach just hasn't +been around quite as long. +However, when comparing side effects +of Minoxidil, cost of Minoxidil, +comparing the efficacy of caffeine +and Minoxidil, +I think caffeine as a topical treatment +for offsetting hair loss stands as +a pretty good choice if you're going +to start exploring this pathway. +There's no reason to think that if you +were to try the caffeine ointment and it +didn't work for you or you didn't like +it for some reason or you needed to stop +it for some reason, +that you couldn't stop it safely, +because it doesn't carry all the other +blood pressure- related effects +and prolactin emia effects +that Minoxidil does. +If you look out there into the hair +maintenance and hair replacement +literature, +and you look at thetreatments that are +being sold, don't be surprised +to see caffeine there. +Also, don't be surprised when I tell you +what I'm about to tell you now, which is, +no, you can't simply just drink more +caffeine in order to accomplish +the goal of offsetting hair loss. +It is true that when you ingest +caffeine, it goes systemically. +However, you have so many adenosine +receptors throughout your body. +Those adenosine receptors, +and the parking of caffeine in those +adenosine receptors, +is the main way in which caffeine +exerts its stimulatory effects, +making you feel less sleepy. +It does that because then adenosine can't +have its effects, +which are to make you sleepy. +Well, those adenosine receptors soak up +so much of the caffeine that you would +ingest orally that very, +very little would make it to the scalp +and to the hair follicles +at the concentrations that you would want, +so that's why you have to rely +on the application of these caffeine +ointments about three times a week. +Keep in mind that no one has really +explored the dosages of caffeine +in these ointments in a systematic way. +We are still in the early stages of all +this, but I do think it's important +to mention caffeine because of the lower +incidence of side effects, +at least reported side effects, +and the general safety margins, +and the head to head essentially +comparable efficacy with Minoxidil +because Minoxidil has +a bunch of other issues. +Now keep in mind that both Minoxidil +and caffeine are generally used as +a preventative for reducing +hair loss over time. +They are not expected, +and they do not, as far- as far as we +know, create new hair growth +to any sufficient degree. +If any of you have used caffeine, +ointments or minoxidil and observed new +hair growth that was robust, +please put that in the comment section. +I'd be curious about those experiences, +but as far as I know +and from the clinical literature that I +read, there's no examples of that. +One other point about caffeine. +It does appear that caffeine can not only +indirectly stimulate IGF-1 and the antigen +phase of hair cell growth by way +of reducing PD and TGF beta. +But it also seems to reduce apoptosis +which is naturally occurring cell +death of that stem cell niche. +We've been talking a lot about +the antigen or growth phase of hair. +We also talked about the catagen or +the recession of that hair +from the inside out. +But remember that third phase, +the telogen phase, where that whole bulb +down at the bottom, the bulge, +as it's called, +gets pinched off and the whole thing dies +and takes the stem cells +off to the grave with it. +It appears that caffeine can offset +the death of that niche and potentially +maintain the stem cell population longer, +making caffeine a really good choice +to think about in conjunction +with the various chemical treatments +aimed at directly attacking the DHT +pathway that we'll talk about next. +So there's one very direct way +to increase hair growth and maintain +the hair that you have on your head, +and that's to increase IGF-1. +That can be accomplished through +prescription drugs such as growth hormone +and things that stimulate the release +of growth hormone and IGF-1. +Keep in mind, growth hormone is released +from the anterior pituitary during +the first hours of sleep, +especially when you haven't eaten +anything for the two hours prior +to sleep, and especially when +you get regular bedtimes. +Yes, this is a real thing. +If you are going to sleep at variable +bedtimes, especially if you go to sleep +much later than your usual habitual +bedtime, you will miss that growth +hormone pulse that normally occurs +in the first 2-3 hours of sleep. +This does not mean that you need to be +neurotic about getting to sleep +at the exact same time every night. +There's probably a plus or minus 30- +minute window, +and it doesn't mean that you can't stay +out late or have a bad night's sleep +every once in a while or get woken up. +Your hair isn't going to fall out. +My dad's story notwithstanding, +your hair isn't going to all +fallout because of that. +But you do want to try and get +that natural growth +hormone release each night. +And as I mentioned, +there are prescription approaches +and those are growth hormone itself. +Things like sermorelin, which is +a peptide that increases growth hormone. +It's actually a secreted dog. +It causes the secretion of growth +hormone and thereby increases in IGF-1. +This is well documented. +Both growth hormone and IGF-1, as I +mentioned, are available by prescription. +They are not without their side effects. +They do cause growth of all tissues. +They do increase height in children, +They increase bone mass and density. +They can increase mainly fat loss, +not so much muscle size, +but they can increase leanness and they +increase hair growth, +They can increase turnover of skin, +they can make skin look more youthful. +All these things sound wonderful. +And yet they also have problems because +they can increase growth of small tumors +that normally might be eliminated. +So there is an increased cancer risk +with growth hormone treatments and IGF-1 +or anything that increases IGF-1 such as +sermorelin or ipamorelin, any of the +peptides that you hear about nowadays. +That said, a number of people are using +sermorelin as an indirect way to increase +IGF-1 and thereby +to increase hair growth. +It does seem to be fairly effective +in doing that, especially when done +in conjunction with other +treatments that we'll talk about. +But keep in mind, these are prescription +drugs and they do carry their own risks. +The other thing about stimulating +the natural production of IGF-1 is that, +as its name suggests, +insulin growth factor one, +it is insulin dependent in many ways, +if not for its secretion, +then for its action at the hair +follicle and stem cell. +So one of the things you really want +to pay attention to is to avoid being +insulin resistant, or rather you +want to try to be insulin sensitive. +So if you're carrying a lot of excess +body fat, if you're obese or if you have +type two diabetes, +meaning your insulin resistant, +you're going to want to deal with that. +There are a number of prescription +treatments to deal with that nowadays. +People are very excited about all the GLP +one agonists, but in addition to that, +regular cardiovascular exercise +and resistance exercise, +making sure that your body fat percentage +is not in excess of where it needs to be. +Everyone has a slightly different idea +of where it needs to be, +both cosmetically and for health. +So that's a conversation between you +and your doctor and you and you frankly. +But you want to avoid being insulin +resistant because being insulin resistant +and being obese can +indeed lead to hair loss. +There are many people out there who are +not obese who nonetheless are experiencing +hair thinning and hair loss because they +are insulin resistant by way +of reduced IGF-1 activity. +There are a few supplements. +So these are over-the-counter +supplements such as myo-i nositol, +taken at dosages of about 900 milligrams +before sleep, which by the way, +can also assist in sleep or things like +berberine or metformin, which are +known to improve insulin sensitivity. +Each and every one of these has its own +profile of positive and negative effects. +The lowest number of side effects is +associated with 900 milligram myo-i +nositol taken about 30 minutes before +sleep, mostly because it can make people +a little bit drowsy +and it does aid sleep in some really +great ways, +but really exercise and maintaining +a healthy nutritional program +are also going to be key. +You just can't discard those. +Berberine, which is a substance made +from tree bark is sometimes +called the poor man's metformin. +Metformin being the equally effective +prescription version of berberine. +Or put differently, +berberine is the non-prescription but +equally effective version of metformin. +Keep in mind that both berberine +and metformin dramatically +reduce blood sugar levels. +And so if you're not going to take them +with carbohydrates, it can lead +to some feelings of discomfort. +That's why I'm not a fan of them. +But if your goal is to really improve +insulin sensitivity, +they are considered very potent tools +on the list of things that can do that. +The other thing that's really important +for maintaining proper hair growth, +this antigen phase, +is that you need sufficient iron. +This is because iron and ferritin play +a key role in the cell growth pathways +that go from the stem cells +to the stimulation of keratin +within the hair itself. +I don't have time to go into this +pathway in a lot of detail, but you can +have your blood levels of iron measured. +This turns out to be pretty important +because you don't just want to start +popping iron supplements because too much +iron can be toxic, +too little means you're anemic. +For women, the levels of iron that you +want are somewhere between 25 and 100. +And for men, somewhere between 30 and 150. +Fortunately, the tests or the blood +tests for iron are usually a very +inexpensive add to your +current blood panel. +So if you're going in for a blood panel +for LDL, HDL, typical things, +or if you're doing the more elaborate +hormone testing, +which I do recommend people do if they +can afford it or if their insurance covers +it, do ask for an iron test as well. +And if your iron is low, +you may need to supplement your iron. +If your iron is too high, +that's not good either. +But iron plays a key role in the antigen +phase of hair growth, so you want to make +sure you at least have sufficient iron. +And if you don't, you want to make sure +that you're getting it from nutrition +and or supplementation. +Earlier, we were talking +about dihydrotestosterone. +Dihydrotestosterone, +just to jog your memory, +is a form of testosterone that combine +the androgen receptor at five times +the affinity of regular testosterone. +Both men and women have a lot +of testosterone relative to estrogen. +It just so happens that men tend to have +more testosterone than women do overall. +But both men and women, as they age, +convert more of the testosterone they +have to dihydrotestosterone +and dihydrotestosterone does two things +that are bad for hair +maintenance and hair growth. +First of all, it shortens the antigen +phase, that growth phase. +Whatever hair is going to grow is going +to occur over a shorter period of time. +Second of all, because of the presence +of androgen receptors on the stem cell +niche area and around it, +it actually miniaturize the follicle +and the stem cell niche. +In other words, it makes the population +of cells that give rise to more hair +protein smaller and can +eliminate it altogether. +And that is why anything that reduces 5- +alpha reductase is going to reduce DHT, +is going to maintain or extend the growth +phase, the antigen phase of hair growth +and is going to offset or prevent some +of the telogen phase, the pinching off +and the removal of that stem cell niche. +Now, one substance that we know can +inhibit 5-alpha reductase, +although it does it pretty weakly is saw +palmetto, which is an extract +of the saw palmetto berry. +To be honest, I don't know how +this was initially discovered. +If anyone knows, please put +it in the show note captions. +When I looked online I found a bunch +of conflicting stories about who was +the first person to start extracting the +extract of the saw palmetto berries. +So I have no idea +which one of those is true. +Maybe somebody can tell me. +The good thing about saw palmetto +treatment is that it is known to have +very few, if any, side effects. +There might be some side effects +in about 1% of people, but it's not +associated with a lot of side effects. +It's also known that when taken at about +300 milligrams per day and here it +doesn't have to be that strict. +Most of the studies that I explored +involved taking anywhere from 200- +500 milligrams of saw palmetto, +but most of them focused on about +300 milligrams of saw palmetto per day, +divided into two or three doses. +Why? +Well, it has a relatively short half-life, +meaning it's going to get cleared +from the bloodstream and more importantly, +its biological action is +going to be very short-lived. +So if you can get a hold of 50 or 100- +milligram capsules or tablets +of saw palmetto and divide those up, +take them in the morning, +afternoon and evening, +or even just in the morning and evening +to achieve a total of about +300 milligrams per day. +That's going to very likely help you hold +on to some of the hair that you would +have otherwise lost, +maybe even grow some new hair. +And I say maybe give you some new hair +growth because saw palmetto is not +known to be a particularly robust +treatment for the reversal of hair loss. +It's known to have some effect, +but it's generally taken in conjunction +with a bunch of other things. +And so it's really hard to tease out +just what amount of hair growth or +prevention of hair loss is due +to saw palmetto specifically. +But I mention it here because +the mechanism of action is logical +and fairly well-known, +which is this week effect in reducing 5- +alpha reductase and thereby reducing DHT. +So again, because it has relatively low +side effects, even though it's not super +effective and because it's fairly low +cost and it's available over the counter, +I felt it was important to include. +Now, as soon as people hear things like +saw palmetto berry, they're probably also +thinking, "Oh boy, +here comes all the herbals." Now keep +in mind that there are some herbal +compounds that have pretty +robust biological effects. +And we talked before in our optimizing +testosterone episodes about things like +Tongkat Ali and Fadogia agrestis, +which taken incorrect dosages +and in the correct way, +can be pretty potent for increasing +luteinizing hormone and free +testosterone that can have huge effects. +It's not like taking exogenous anabolic +steroids, but they can have real effects. +And so herbal compounds can be potent. +However, I do acknowledge that there is +a vast market out there of herbal +compounds and plant-based +compounds that people are arguing. +Mostly the people who sell them are +arguing can increase hair growth. +There are some decent +studies of these things. +The hard part about studying these herbal +compounds and these plant-derived +compounds for increasing hair growth is +that they are often taken +in combination with one another. +In fact, most of the hair growth +supplements that involve these herbal +compounds and plant compounds include 5 +or 10, sometimes even +more things altogether. +So teasing out which ones are effective +and which dosages are effective +is nearly impossible. +There are just too many variables. +You will hear, for instance, +that green tea extract, Reishi Mushroom, +pumpkin oil, zinc, curcumin, all +of these things can increase hair growth. +Perhaps the only thing on that list +that makes logical sense with respect +to the biochemistry is that curcumin is +known to, in some people, +be a potent inhibitor of 5-alpha reductase +and DHD so much so that I can personally +say for me I once took curcumin, +turmeric, it's also called in high dosage. +This is about a gram to 2 gram capsules +and I felt absolutely terrible. +I mean, just dreadful. +I don't care if it allowed me to keep +my hair forever, I would rather +lose all my hair three times over. +I guess that means it +would have grown back. +I'd rather lose all my hair. +Let's just put it that way +than ever take curcumin or +turmeric in high dosages again. +In saying that, I know that many people +take turmeric and curcumin and really like +its anti-inflammatory properties +and don't experience any side effects. +I just happen to be particularly sensitive +to curcumin by way of this DHT pathway. +I know this by way of blood work, so I'm +never going to hear that stuff again. +That said, a lot of these herbal compounds +and cocktails probably will have some +minor marginal, +infinitesimally small, +somewhere in that range effect +on maintaining hair growth or +in stimulating new hair growth. +It's just that there really aren't +clinical studies +to support any one of them. +And that's why I singled out saw palmetto +as one of the few +for which the biochemical pathway +of inhibiting 5-alpha reductase +and the low incidence of side effects +and the fact that many people have used it +with some degree of success +makes it a standalone. +I wouldn't say recommendation, +but a consideration. +Another commonly discussed and use +commercial compound for offsetting hair +loss and stimulating hair +growth is ketoconazole. +Sometimes this is known as Nizoral where +Nizoral is the brand name of a shampoo. +Ketoconazole is an antifungal that was +initially developed to treat +dandruff and severe psoriasis. +Ketoconazole has been shown to be +effective in increasing hair number. +It's also been shown to be effective +in increasing hair diameter, +which is somewhat surprising because one +of the common side effects of ketoconazole +is drying, thinning and brittle hair. +So what's going on there is +a little unclear. +We'll return to that in a moment. +The mechanism of action +for ketoconazole is pretty interesting. +Remember earlier we were talking about +the sebaceous gland and the production +of sebum, that oily stuff +whose very name seems to evoke +disgust in certain people. +Well, ketoconazole can disrupt some +of the fungal growth that frankly, +we all have on our scalp all the time. +I know this is a surprise to many of you, +but you are constantly bombarded +with viruses, bacteria +and funguses all the time. +But we managed to battle those off +with our immune system, +either by physical barriers such as +an oil barrier like the sebum +or through antimicrobial action. +Chemical approaches our immune system, +the sebum, etc, +ketoconazole acts as an antifungal +that in some way seems to reinforce +the properties of sebum at keeping +out other fungal infections. +And the net effect, at least as far as +we know, is a mild reduction in DHT. +Now exactly how this +happens isn't really clear. +What is clear is that the use +of ketoconazole shampoo is +2-4 times per week with a scalp contact +time of about 3-5 minutes has been shown +to give about an 80% response rate +of maintaining hair +that would otherwise be lost. +So that's pretty dramatic, 80%. +What is less clear is whether or not +ketoconazole shampoo can actually +stimulate new hair growth. +But as you're probably starting +to realize, +this is always a bit of a tough thing +to disentangle maintenance of hair +that you would have lost +versus new hair growth. +Certainly, +that's an easy thing to disambiguate if +you have a patch of scalp where there is +absolutely no hair, +these so-called dead zones that you +can resurrect with certain treatments. +But what about areas of your +scalp where hair is thinning? +So, for instance, on the top of your head, +this is where many women will first +experience pattern, hair loss. +Alopecia is right at their midline, +especially if they +have a part right there. +They'll start to notice that under very +bright light, +fluorescent lights in particular, +they'll notice a thinning of their +hair there or in the forehead region. +They'll start using ketoconazole shampoo. +Again, the typical recommendation is 2-4 +times per week with a scalp contact time +of 3-5 minutes and really rubbing +it in and then rinsing it out. +You don't need to be super vigorous, +but you want to make sure that it gets +down into the follicle and around +the follicles, not just sitting on top +of the hair, +which is going to be especially +important for people who have +long hair to really massage it in. +Well, they will experience a growth +of hair in that particular region +that almost certainly were due +to miniaturization of the hair follicle +and reduction of the total population +of stem cells in that follicle as opposed +to complete loss +of the stem cell population. +The reason we say this is that there's no +reason to think that ketoconazole can +actually stimulate +IGF-1 or activate growth itself. +It's probably offsetting some +of the reductions in the antigen phase +and some of the exacerbation +of the telogen phase. +Now, if you decide to use ketoconazole as +an approach to offsetting hair loss, +it's very important that you get a hold +of a shampoo that's at least 2% +concentration of ketoconazole. +This is important because a lot +of the ones that are available out there, +especially online, +are going to be 1% or lower. +So you want to try and obtain +a ketoconazole shampoo of 2% or higher +concentration of ketoconazole because +it has other things in it, of course. +I should mention that there are occasional +side effects with ketoconazole. +The rates of side effects from the meta +analyzes and reviews that I read were +somewhere between 1% and 8% of people +will experience some side effects, +but those side effects +tend to be pretty mild. +Things like irritation of the scalp, +things like thinning and brittleness +of the hair that sometimes can be offset +by using shampoos that contain +things like biotin. +I know many people are probably curious +about biotin, which is a protein that can +be incorporated into the keratin. +Whether or not different biotin enriched +shampoos can really enhance the total +amount of biotin that gets incorporated +into the hair isn't clear, +but it is clear that having sufficient +biotin around is important. +So if you get a little bit extra +from your shampoo, +you can imagine how that would "tap +off" the amount of biotin in that hair. +And there are people out there saying +that by biotin-enriched shampoos +have done wonders for them. +Who knows? +I'm not going to dispute their experience. +So if you're going to use ketoconazole, +keep in mind that the more typical brand +names that are out there, +you know which ones they are, +oftentimes don't have 2% or if they do +have 2%, they can be very drying +and lead to brittle hair. +There are newer and now fortunately, +a greater variety of ketoconazole +containing shampoos. +We as a podcast and I don't have any +affiliation to any of these, +but I will provide a links to a couple +of the more prominent ones that are known +to have 2% concentration of ketoconazole, +as well as some other things in them known +to offset some of that dryness +and brittleness that ketoconazole +shampoos can trigger. +So by now, I think it will be abundantly +clear why inhibiting 5-alpha reductase +and thereby reducing DHT should increase +hair growth because of the negative +impact that DHT has on the hair follicle. +The major player in this whole story +around inhibiting 5-alpha reductase +and reducing DHT to maintain or increase +hair growth is going to be finasteride +and its close cousin, dutasteride. +Finasteride is effective in reducing DHT +because of its actions in reducing +the type two isoenzyme or +isoform of 5-alpha reductase. +It turns out there's three different +isoforms or what are sometimes called +isoenzymes of 5-alpha reductase. +This is getting pretty +far down in the weeds. +What I think most of you just need +to know is that finasteride reduces DHT, +that's the net product of finasteride +and in doing so, it can increase +hair count by as much as 20%. +Pretty remarkable if you think about it. +In addition, finasteride treatment done +properly, which we'll define in a moment, +can reduce hair loss in 90% +of all people that take it. +That is near staggering. +I mean, there aren't many pharmaceuticals +Out there that have that +efficacy, really dramatic. +In addition, it's known to increase hair +thickness by about 20- 30% overall, +so not just create new growth of hairs, +and thicker hairs, but whatever hair you +do happen to have on your head, +it can further thicken those. +The finasteride story is one, +I think, of general success. +It really seems to improve hair growth, +and help you hold on to +the hair that you have. +The issue with finasteride is twofold. +First of all, it is known to have some +pretty significant side effects if it's +not dosed properly, +and in particular populations of people. +This is because there is a wide variation +in the amount of the different +Isozymes that people make. +This is why I brought up +the Isozymes earlier. +Some people make more of Isozyme one +and three, some people make more of +Isozyme two and three, +and every variation thereof. +When people take finasteride, +some people are very strong responders, +and they achieve really effective +hair regrowth and maintenance of hair. +Other people less effective, +although still pretty impressive. +But the catalog of side effects +that people experience +at a given dose, varies widely. +There's a lot of trial +and error that has to take place. +Also, I should point out that finasteride +comes in two major forms. +There's an oral form +and there's a topical form. +This is not unlike our +discussion of minoxidil earlier. +Topical finasteride is typically taken +in 1% solution or ointment and rubbed +into the head, sometimes it's now also +incorporated into shampoos, +but typically it's put into a solution +that people rub into their head, +and it is thought that the 1% solutions +are equivalent to one mg +of systemic finasteride. +Now we need to take a step back and ask +why was finasteride +developed in the first place? +Well, finasteride, as a fairly potent five +alpha reductase inhibitor, +it's great at lowering DHT. +It was developed for treatment +of prostate enlargement and various +issues of the prostate that are +associated with elevated DHT +that occurs with age. +The topical finasteride were designed +with the hope that the finasteride would +make it into the hair follicle, +and would inhibit DHT there and allow +for more growth of the hair, +which apparently it does, +but not make it into the systemic +circulation, +or at least not at concentrations +sufficient enough to cause as many +side effects as with the oral dosing. +Now, the problem is, it does +make it into systemic circulation. +The issue is also, +that topical application of finasteride +is harder to dose than oral finasteride. +I'm not saying you should be taking oral +rather than topical finasteride, +but keep in mind that the dosages +of finasteride that have been shown to be +effective for inducing hair growth, +cover an enormous range. +As low as 0.01mg per day and as high as +five mg per day, which is +a just staggering range. +Now, when trying to simplify the problem +of how much finasteride to take, +either by way of oral tablet, +or by way of topical solution, +we can get a bit of leverage on this +by thinking about how much DHT +reduction occurs as a function of dose. +There, finasteride shows this really +interesting, what's called +logarithmic distribution. +What it means is that, +for a dosage of 0.01mg of finasteride, +you're going to achieve approximately +50% reduction in DHT, +and that's systemic DHT, +so this is a blood draw measuring your +DHT, then taking 0.01mg of finasteride. +Again, 0.01, very low dose of finasteride, +repeated a couple of weeks, +measure people's DHT in their blood again, +and you see that it's reduced by 50%. +However, at increasing dosages of 0.2mg, +one mg, five mg of oral finasteride per +day, over the same period of time, +the increase or I should say +the reduction in dihydrotestosterone, +doesn't increase linearly. +It's not that you go from 50%-6 0%-75%- +100% with each increasing dose, +it tapers off, it flattens out. +It tends to increase a little bit, +but it's a gradual slope increasing +as you head from 0.2mg out to five mg. +What this means is that given +that reducing DHT can cause various side +effects, sexual side effects, +reductions in either sexual function or +sexual drive, as well as overall drive +and motivation, +sometimes even some depressive symptoms +that everything points to taking +the lowest effective dose of finasteride +and starting with a very low dose +of finasteride because low doses +of finasteride, even at that 0.01mg taken +orally daily, +are already leading to a 50% reduction +in dihydrotestosterone and thereby taken +for a long enough period of time, +should offset hair loss +and stimulate hair growth. +One of the problems, however, +is that people will start taking +finasteride at a low dose 0.1mg or 0.2mg, +maybe even 0.01mg, +and there will be a reduction in their +DHT, but because of the long duration +of that antigen phase, +they don't see a lot of change in hair +growth in the first month or even two +months, and so what they end up doing is +increasing their dosage and then they +start to see hair growth, but then they +start to experience more side effects. +Now the side effects of oral finasteride +are serious enough and common enough +in people that take finasteride +that the topical solutions were developed, +but there are two one needs to exercise +caution because if we are going +to translate between topical finasteride +and oral finasteride, +with the understanding that topical +finasteride can actually make it +into the systemic circulation, +we need to look at what's been shown +in clinical studies, +which is that for instance, +taking one ml of 0.25% finasteride applied +to the scalp, this is a very typical +recommendation, translates to the same +thing that would be achieved +with 2.5mg of oral finasteride. +When I say translates to the same thing, +what I mean is it leads to the same +concentrations in the blood. +Now consider that 0.2mg, 0.2mg +of finasteride in the blood is known +to be effective in generating new hair +growth and maintaining hair that one +already has when they start the treatment. +If you think that the topical +finasterides are actually creating lower +overall systemic concentrations +of finasteride, that is +not necessarily the case. +Again, one ml of topical finasteride +at 0.25% leads to a 2.5mg concentration +in the blood, when the effective dose +within the bloodstream by taking it orally +as a pill is 0.2mg. +That might not seem like a big deal +to you, although it is a big deal, right? +We're talking 2.5mg versus 0.2, +but it is a huge deal when you consider +that the side effects of finasteride +increase as you increase the concentration +of finasteride in the bloodstream. +Where does this leave us? +Should people who are interested +in taking finasteride take the oral form +at low dose or take the topical form +and simply try and apply it less often or +guess at what their systemic +concentration of finasteride is. +Well, it's going to vary +from person to person. +Some people are very sensitive +to finasteride and not in the good sense. +The side effects just really show up +quickly and they tend to be dramatic. +Other people, not so much. +The dosage recommendations that I was +able to arrive at based on the clinical +studies and frankly in discussion +with some doctors who prescribe +finasteride were the following: 0.5mg +to one mg of finasteride as a tablet per +day seems to be an effective and pretty +safe starting place for most people. +Now some people will find that even +that 0.5mg dosage is just going to cause +side effects that are not going to work +for them, and they're going to either have +to reduce their dosage of finasteride or +move to the topical or maybe cease +taking finasteride altogether. +But for many people out there, +that's going to be pretty well tolerated. +The key thing here is that one is going +to have to wait some period of time +to see whether or not +any hair growth occurs. +It is a naive and frankly foolish +approach based on what we know about +the duration of that antigen phase +of the hair to do one of these +treatments, wait a week or two +and then decide to up your dose. +Now, it is not foolish to reduce your dose +if you're experiencing bad side effects, +but to simply increase your dose because +you're not getting results quickly enough, +that's not going to be the best approach. +I really encourage people who are going +to explore the finasteride route, +to think of this as a long-term project +and to really ratchet up slowly if at all, +starting initially with a low dose taken +for a long period of time, +maybe even as long as 25 weeks before +considering going up any further. +Certainly, as I mentioned before, +if you need to go down further, +that's not going to be a problem, +at least not in terms of reducing side +effects, you're not going to get +additional hair growth, +but you're certainly not going to increase +your side effects if you reduce your dose. +However, I will talk a little bit later +about post-finasteride syndrome, +which is something that's getting +increasing attention nowadays. +That's something that occurs after +people have taken finasteride +for an extended period of time. +Now some of you have perhaps heard +and I'll just tell you right here, +that the topical forms of finasteride are +associated with far less side effects. +Now that might come as surprising given +that topical application of finasteride +can lead to systemic +distribution of finasteride. +But the numbers that are out there right +now, it's that topical finasteride is +associated with 30-50% fewer side effects +or 30-5 0% less severe side +effects than oral finasteride. +There are several things +probably responsible for that. +One is that people tend to ratchet up +their dose of oral +finasteride pretty quickly. +But keep in mind that the effective dose +of finasteride in the blood is 0.2mg. +Earlier I said the typical topical +finasteride solutions are 0.25%. People +are taking one ml of it, +that equates to 2.5mg, +and so it seems like a massive overdosing +but here's the discrepancy and here's +where we can arrive at some +reasonable recommendations. +If you decide that finasteride is +right for you, you get a prescription. +I would hope that you're monitoring your +DHT levels and other hormone levels +that would be ideal, +and working with a doctor, please. +0.5mg to one mg per day of oral +finasteride seems to be +the best starting place. +For topical finasteride. +It's going to be that one ml of 0.25% +that we talked about earlier, +but that's taken only one time per week, +and you can fully expect that right after +the application you will have higher +levels of finasteride in your bloodstream, +and therefore lower levels of DHT +and that will alter across the week. +Most people are not going to be able +to measure their DHT on a day +by day or even weekly basis. +It's just too expensive +and labor intensive. +But I think those dosing regimens ought +to get people into more or less the same +category of optimizing hair maintenance +and hair growth while minimizing +finasteride side effects. +One point about finasteride taken either +alone or in combination is that in recent +years, really in the last five or so +years, there's been increasing discussion +about so-called post- +finasteride syndrome. +Now post-finasteride syndrome is indeed +a new phenomenon in the sense +that finasteride has been prescribed +for a very long period of time +for treatment of the prostate, +at dosages of about five mg per day. +That's a very high dose. +Sometimes lower, but as high as five mg +per day, and for many years there was no +discussion about this +post-finasteride syndrome. +What is post-finasteride syndrome? +Post-finasteride syndrome is +when typically it's males. +This is where it's been described. +We'll take finasteride at any range +of dosages, from 1mg to 5mg per day. +They're either doing this for prostate or +more likely they're doing it to offset +hair loss and increase hair growth, +and then they stop taking finasteride +for whatever reason, +financial or it wasn't working for them +or the side effects were not to their +liking, and they start to experience some +very severe what can only be called +syndrome effects, +such as very reduced libido, +very reduced erectile function, +very reduced mood to the point +of depression, even suicidal depression. +This is pretty scary stuff, +especially since it's occurring at an age +when most of these things are +not typically occurring in males. +They can occur, but they're not typical +of younger males in their +20s and 30s and early 40s. +We have to ask ourselves +what's going on here? +After all, people have taken finasteride +for the prostate at fairly high dosages +without this post-finasteride +syndrome when they've stopped. +Now these young males are taking +finasteride, +they're coming off finasteride +and they're getting this very severe, very +debilitating post-finasteride syndrome. +This has become a hot topic, +enough so that medical doctors who have +been prescribing finasteride for a very +long time, have been +forced to address this. +I think at first they were perplexed +and thought, I don't know, this might +be psychosomatic, whatever that means. +As a neuroscientist who works on mind-body +connection, we know that nothing +is truly psychosomatic. +Everything is of the mind and body. +But the point is that enough medical +attention has been placed on post- +finasteride syndrome and trying +to unravel exactly what that is. +Where there are now a few general +conclusions about what might be going on. +First of all, it seems that younger males +taking finasteride in particular high +dosages to improve hair growth or offset +hair loss seems to be +one of the key variables. +We're not seeing this post-finasteride +syndrome as much in older males. +In fact, it seems to occur more in males +in their 20s and 30s than +males in their 40s and older. +One thing and it may relate to the ways +in which Dihydrotestosterone, we know, +has a very key role in early +embryonic development. +It's actually what's responsible +for the male genitalia. +It's also responsible for certain things +in female development, +but mainly in utero, +it's responsible for male development and +development of the penis in particular. +Then around the time of puberty, +Dihydrotestosterone acts again, +in what's called its activating effects +to further increase growth +of the genitalia, increase the musculature +bone growth, et cetera, and increase +libido and a number of other things. +It's probably also involved +in the activation of puberty. +It's certainly not the only hormone +involved in the activation of male +puberty but it's certainly +one of the key players. +Dihydrotestosterone has these known early +roles in embryonic development +and in puberty, but what post-finasteride +syndrome seems to indicate is +that Dihydrotestosterone is likely having +further effects on male maturation, +in particular, +maturation of the hypothalamus in areas +of the brain that continue well +into one's 20s and maybe even one's 30s. +Here I just want everyone to keep in mind +that we tend to think about development as +childhood, teenage years, young adulthood, +adulthood, but really +development never stops. +Development is something that starts +at conception and birth, of course, +and then extends all the way out +until the point when we die, +so even if we live to be in our late 90s +or achieve 100 years of age, +development is occurring that entire time, +and these different hormones such as +Dihydrotestosterone are having different +impact for across the lifespan and +in different ways across the lifespan. +There isn't a clear conclusion about what +post-finasteride syndrome is really all +about, but it points to the fact +that DHT is likely to be involved +in development of the brain and the brain +to genital axis, +because I mentioned that because so many +of the side effects +that are associated with this +post-finasteride syndrome seem to center +on sexual side effects, although there +are also the depressive side effects. +Of course, those can be related +to one another in either direction. +While I do understand that loss of one's +hair, or potential loss of one's hair can +be particularly troubling and anxiety- +provoking, even cause depression +in some cases, I am sensitive to that. +You also want to be sensitive +to the fact that some of these treatments, +such as finasteride, +can carry very serious side effects even +if you come off them AKA +post-finasteride syndrome. +As long as we're talking about finasteride +and this general pathway of 5α-Reductase +inhibition and thereby DHT inhibition +and on and on topics and themes +and nomenclature you are now very familiar +with, we have to talk about dutasteride. +Dutasteride is yet another molecule +similar to finasteride, +but remember those three isoforms +of the 5α-Reductase enzyme? +Well, it inhibits all three, +mainly type one and type two, but also +type three, and it does it very potently. +As a consequence, +the typical dosage of oral d utasteride, +get this, 0.5mg to 2.5mg taken orally, +works 2-5 times faster than typical +finasteride at inducing hair regrowth +and reduces DHT by, get this, 95%. +It's just near flatlines DHT, +and that can occur at concentrations as +low as 0.5mg, although you will see +prescriptions and people taking d +utasteride anywhere from 0.5 mg +all the way to 2.5mg orally. +Now, not surprisingly, +dutasteride is associated with a lot of +side effects related to the DHT pathway. +Things like reduction in sex drive, +reduction in overall drive, +it also tends to impact other hormone +pathways, so it increases +in estrogen prolactin. +That's why gynecomastia, +growth of male breast tissue sometimes +occurs when people take dutasteride and so +you're probably asking, +why would anyone take dutasteride? +Why not just take finasteride +and wait for that hair growth? +Well, +the answer is that people are often very +impatient, and it turns out that d +utasteride works, about 2-5 +times faster than finasteride. +Some people don't want to wait a full 30 +weeks or 40 weeks or 50 weeks or more +in order to grow their hair back, +and they're very concerned about +the hair loss that's occurring. +They will take what I hope would +be a very low dose of dutasteride. +I realize that there are ways +to take dutasteride that can be safer, +off set some of these side effects. +But by my read of the literature, +if one is going to try to mildly inhibit +the DHT pathway, things like saw palmetto, +things like topical caffeine, +which has some effect on the androgen +pathway, but as we talked about earlier, +tickles other pathways, +things like ketoconazole, +mild reduction in androgen receptor +pathways in the follicle and very direct +because it's applied +directly to the scalp. +Things like that are going to be the best +route for mild reductions in DHT as +an attempt to maintain hair or grow hair. +Whereas if one really wants a potent +stimulus for increasing hair growth, +that's very likely going to be +finasteride, and hopefully low enough +dosages of finasteride and hopefully +a patient enough patient person that they +are willing to wait the duration of time +required for that hair growth to come back +because they understand that their +antigen phase takes some time. +Now the holy grail of all this hair stuff +is in understanding that no one specific +treatment is magic, and in fact, +there are now a number of good meta- +analysis comparing the various +treatments we've talked about +today alone or in combination. +We can summarize that pretty easily +by saying that combination treatments +that involve a mechanical stimulus +and a chemical stimulus are always going +to be better than either one alone, +and within the mechanical category, +the stimulus that seems +to work best is microneedling. +The combination of microneedling +and finasteride, can lead to some pretty +robust and impressive hair regrowth, +so much so that people that were... +I would only describe them as pretty bald +or bald, can regrow +significant amounts of hair. +I've never seen examples of people +who were completely bald, +meaning lacking all scalp hair to grow +back a full head of hair, +but the combination of microneedling +and finasteride is probably +the most effective way to go. +If you're going to do that, +there's no reason why you couldn't also +use ketoconazole shampoo, +could also use saw palmetto. +There's no reason to think that these +things collide with one another, +although anytime you're inhibiting a DHT +pathway, or whether or not you're +increasing or decreasing any hormone +pathway for that matter, +you want to be careful about layering +in too many different treatments because +you don't want your DHT +level to go too low. +Let's keep in mind that even if you take +a very low dose of finasteride and reduce +your DHT and don't have side effects, +maybe just the mere addition of +saw palmetto, which leads to a slight +reduction in DHT combined with some +caffeine ointment, +would be sufficient enough to start +inducing some of the low +DHT associated side effects. +You really have to see for you, +and that's one of the major issues +in this whole field of hair growth +and regrowth is that people are highly +individual in their response, +and in their side effect profile +to these various treatments. +There's an enormous range there +and unfortunately, there's no way to know +a priori before doing these treatments +what your response is going +to be in terms of side effects. +You're simply going to have to explore, +and I would hope that you would explore +starting with minimal, +possible effective dosages, +and to do that in coordination +with a medical professional so you could +really evaluate these things that the +level of blood, and cosmetic changes. +In fact, that's a pretty good motivator +for thinking about the different +treatments that we talked about today. +Everything from mechanical treatments, +as simple as massage, +which we've all heard about, +but for which there really aren't a lot +of data for supporting hair growth. +But certainly things like microneedling, +which is a mechanical stimulus +for which there are pretty good data +that it can improve hair growth. +Also things like saw palmetto, +a weak DHT antagonist. +Also things like ketoconazole shampoo, +which again is a weak DHT antagonist +and operates through some other pathways +as well to stimulate hair growth. +My suggestion is that anyone young, old, +male, female, who's thinking about +embarking on various treatments for +offsetting hair loss and stimulating hair +growth, consider both mechanical +approaches, and the approaches that attack +the chemical pathways, +that can stimulate hair growth, and can +inhibit the inhibitors of hair growth. +In fact, that's the reason why we spend so +much time on the biology of hair growth +and what shuts down hair growth early +on in today's episode, +and then systematically went through each +of the various treatments that relies +on and in some cases hinges entirely +on either a mechanical stimulus or +a chemical stimulus in order +to exert its effects. +My goal today was not to overwhelm you +with a ton of biology about hair, +although we did cover a lot of biology +of hair and stem cells and hair growth. +My goal in describing all that was really +for you to be able to hear about various +treatments, whether or not it's lasers or +PRP or finasteride, dutasteride, +or whatever is coming next that we're +sure to hear about soon online +and from the medical community, +and to be able to place those into bins +related to their known or potential +mechanisms and then to be able to step +back and evaluate, which, if any, of those +treatments might be right for 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If you're not +already following me on social media, +I am Huberman Lab on Instagram, +Twitter, Facebook, and LinkedIn. +Especially on Instagram, +I cover science and science- related +tools, some of which overlaps +with the content of the +Huberman Lab podcast, +but much of which is distinct from the +content of the Huberman Lab podcast. +Again, it's Huberman Lab on Instagram, +Twitter, Facebook, and LinkedIn. +If you haven't already subscribed to our +Huberman Lab podcast Neural Network +newsletter, this is a zero-cost +newsletter that we send out each month. +It includes summaries of podcast episodes +and we have what are called tool kits. +Those tool kits range from how +to optimize your sleep to how +to optimize neuroplasticity. +We have toolkits for dopamine, +we have toolkits for deliberate cold +exposure, heat exposure, +exercise and much more. +Again, it's totally zero cost to sign up. +You simply go to hubermanlab.com, +go to the menu tab, scroll down +to newsletter and supply us your email. +We do not share your email with anybody. +Thank you for joining me +for today's discussion. +All about the biology of hair and hair +growth, how to hold on to the hair you +have and to stimulate new hair growth. +Last but certainly not least, +thank you for your interest in science. +[MUSIC PLAYING] \ No newline at end of file