The Science of Healthy Hair, Hair Loss and How to Regrow Hair

**Andrew Huberman** (0:00)
Welcome to the Huberman Lab podcast, where we discuss science and science-based tools for everyday life.
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. And 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. So when your brain and your nervous system develop, it develops from a small batch of cells that turns into many, many trillions of cells. And it does that by cell replication, something that we call the cell cycle. And 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. So for instance, the hairs on your head will undergo ongoing growth for four to six or even eight years. So 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 eight 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. So 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. And 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. So 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. And we will talk about the chemical and mechanical approaches to halting and reversing hair loss. Everything from minoxidil to dutasteride, to ketoconazole, to micro-needling, 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 at age 50 or age 60 or 75, and determine whether or not you'll have the exact same pattern of hair loss. So that's a myth that I'd like to dispel right here and now. And 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. 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. So 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. So for me, it matched me to the Dusk, D-U-S-K mattress. And I've been sleeping on a Dusk mattress for over two years now. And my sleep has been better than it ever was previously. So if you're interested in upgrading your mattress, go to helixsleep.com/huberman.