How to Improve & Protect Your Skin Health & Appearance | Dr. Teo Soleymani

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. My guest today is Dr. Teo Soleymani. Dr. Teo Soleymani is a double board-certified dermatologist and dermatologic surgeon. He did his training at Stanford University, and he was a clinical professor of dermatology and dermatologic surgery at UCLA, that is the University of California Los Angeles. Today, we discuss all things related to skin appearance, skin health, and skin longevity. For instance, we discuss sun exposure and the impact it can have on both the appearance and health of one's skin. In reference to that, we discuss sunscreens, which ones are safe, which ones perhaps elicit a bit more concern or perhaps should be avoided, and we discuss the surprising relationship between sun exposure and skin cancer. We discuss laser treatments for the skin, both for the appearance of skin in order to make it appear more youthful, as well as to prevent certain forms of skin cancer. We discuss retinoids, we discuss supplements and nutrition, all in reference, again, to skin health and appearance. Thanks to Dr. Soleymani's incredible depth of expertise, as well as clarity of communication about the dos and do nots that relate to skincare and appearance and to avoiding and treating skin cancers, by the end of today's episode you will be armed with an immense amount of knowledge that is the very latest in our understanding of how to improve and protect your skin.

Andrew Huberman 1:35 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 ROKA. ROKA makes eyeglasses and sunglasses that are of the absolute highest quality. 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 different challenges in order for you to be able to see clearly from moment to moment. ROKA understands all of that and has designed all of their eyeglasses and sunglasses with the biology of the visual system in mind. ROKA eyeglasses and sunglasses were first designed for use in sport, in particular for things like running and cycling. And as a consequence, ROKA frames are extremely lightweight, so much so that most of the time you don't even remember that you're wearing them, and they're also designed so that they don't slip off even if you get sweaty. Now, even though ROKA eyeglasses and sunglasses were initially designed for sport, they now have many different frames and styles, all of which can be used not just for sport but also for wearing out to dinner, to work, essentially any time and any setting. I wear ROKA readers at night, or ROKA eyeglasses if I'm driving at night, and I wear ROKA sunglasses in the middle of the day anytime it's too bright for me to see clearly. My eyes are somewhat sensitive, so I need that. I particularly like the Hunter 2.0 frames, which I have as eyeglasses and now as sunglasses, too. If you'd like to try ROKA, you can go to roka.com/huberman to get 20% off your purchase. Again, that's roka.com/huberman to get 20% off. Today's episode is also brought to us by Joovv. Joovv makes medical-grade red light therapy devices. Now, if there's one thing I've consistently emphasized on this podcast, it's the incredible impact that light can have on our biology. Now, in addition to sunlight, red light and near-infrared light have been shown to have positive effects on improving numerous aspects of cellular and organ health, including faster muscle recovery; improved skin health and wound healing; even improvements in acne, reducing pain and inflammation; improving mitochondrial function; and even improving vision itself. What sets Joovv lights apart and why they're my preferred red light therapy devices is that they use clinically proven wavelengths, meaning it uses specific wavelengths of red light and near-infrared light in combination to trigger the optimal cellular adaptations. Personally, I use the Joovv handheld light both at home and when I travel. It's only about the size of a sandwich, so it's super portable and convenient to use. I also have a Joovv whole-body panel, and I use that about three or four times per week. If you'd like to try Joovv, you can go to Joovv, spelled J-O-O-V-V, .com/huberman. Joovv is offering an exclusive discount to all Huberman Lab listeners with up to $400 off select Joovv products. Again, that's Joovv, J-O-O-V-V, .com/huberman to get $400 off select Joovv products. Today's episode is also brought to us by Helix Sleep. Helix Sleep makes mattresses and pillows that are customized to your unique sleep needs. Now, I've spoken many times before on this and other podcasts about the fact that getting a great night's sleep is the foundation of mental health, physical health, and performance. Now, the mattress we sleep on makes an enormous difference in terms of the quality of sleep that we get each night. We need a mattress that is matched to our unique sleep needs, one that is neither too soft nor too hard for you, one that breathes well and that won't be too warm or too cold for you. If you go to the Helix website, you can take a brief two-minute quiz, and it asks you questions such as, do you sleep on your back, your side, or your stomach? Do you tend to run hot or cold during the night? Things of that sort. Maybe you know the answers to those questions, maybe you don't. Either way, Helix will match you to the ideal mattress for you. For me, that turned out to be the Dusk mattress, D-U-S-K. I've been sleeping on a Dusk mattress for, gosh, now more than four years, and the sleep that I've been getting is absolutely phenomenal. If you'd like to try Helix, you can go to helixsleep.com/huberman, take that brief two-minute sleep quiz, and Helix will match you to a mattress that is customized to your unique sleep needs. Right now, Helix is giving up to 25% off mattresses and two free pillows. Again, that's helixsleep.com/huberman to get 25% off and two free pillows. And now for my discussion with Dr. Teo Soleymani.

Andrew Huberman 5:45 Dr. Teo Soleymani, welcome.

Dr. Teo Soleymani 5:48 Thanks for having me. Uh, it's, uh, awesome to be here. I'm very, very privileged to be here. Thank you.

Andrew Huberman 5:53 Oh, well, it's an honor to have you. Let's talk about this amazing organ we call skin. So skin...... of course, covers our other organs. It's its own living biological entity and just for sake of educational purposes and to frame the rest of what we're going to talk about, how much turnover is there in our skin? Meaning, the skin that I'm wearing right now, is that going to be 100%, 50% of the skin that I'm going to be wearing a year from now? I'm 49 years old, so...

Dr. Teo Soleymani 6:31 Well, you look great for 49, so whatever you're doing, k- keep it up. So, uh, the skin's an amazing organ, just like you said. It's the largest organ, the largest dynamic organ we have in our body. You have new skin, brand new skin every 28 days, so the surface of your skin turns over about every month. Now, the stem cells, which are in the lowest portion of our epidermis, uh, remain and they generate the skin cells, but you have brand new skin the same way you have new gut lining every 28 days. It's amazing for many reasons, because the skin is one of the few organs that can regenerate because of this. So you can grow new skin, you can test things on skin. If your skin gets injured, it will regenerate and heal itself, whereas many other organs cannot do that. And because of this, it also allows us to use it as a model platform for studying diseases of all kinds, so skin's an amazing organ. I mean, I guess I'm biased, but...

Andrew Huberman 7:33 Well, uh, I find a 28-day turnover just to be incredible. The skin, as I understand it, is innervated, that is, it receives connections from the nervous system. So I think for many people, their interest in skin is skin appearance, although we will also talk about skin health. But in terms of skin appearance, how much does stress, short-term and longer term stress, impact the appearance of our skin, and how does that work? I could imagine that the neurons release certain things into the skin. Um, does stress make our skin age faster? Does that mean it turns over more quickly or turns over more slowly? Maybe you could link these two aspects of our biology for us.

Dr. Teo Soleymani 8:16 Yeah. That, that's a great question. So in order to understand that, we have to just look at the, the structure of the skin. So the s- skin generally is three layers, the epidermis, the dermis, and the subcutaneous fat. And the dermis is where most of the biologic activity resides. That's where our blood vessels are, that's where the nerves that innervate sensation and movement reside, that's where our hair follicles, oil glands and sweat glands reside. So stress has two components. There's what we call acute stress, meaning stress that happens within a short period of time, and then there's long-term stress or chronic stress, and both have different, uh, processes in the skin. And you see the results of stress both immediately in the skin with release of certain chemical messengers in an autocrine, paracrine, and holocrine fashion, and then you see the long-term deleterious effects of stress in a different mechanism in which there's actually breakdown of the skin. The easiest way to see this is when people are stressed and they lose their hair, and the hair obviously is an extension of our skin. It's a biosensor of our wellbeing, and we see this all the time. You know, I s- see students during finals time where they're really stressed out and they're coming with their hair falling out, or after a large medical illness or a pregnancy, patients will come in and say their hair is falling out. So that acute stress is seen right away, and that's due to several different reasons and release of messengers and, and hormones and, and chemical mediators that, that do this. Long-term stress is usually mitigated or caused by cortisol, and everybody knows cortisol. It's the, you know, fundamental stress hormone of our body. It falls in the same family as drugs that we give, like Prednisone, um, falls in the same family of cholesterol, testosterone, estrogen, but cortisol does something very different. It breaks things down to allow our body to utilize it in times of stress, 'cause unfortunately, our body doesn't understand the difference between 21st century stress and old stress. So us being chased by a lion, to our, to our body's messaging system, is the same as meeting chronic deadlines at work. And what happens is cortisol is responsible for the breakdown of things like collagen and elastin, thinning of vessel walls, which allow our skin to look supple and healthy. So as we have a lot of stress and a lot of cortisol release, we see aging, and there's accelerated aging studies that look at patients and people who are under high periods of stress. A great example of studies we look at presidents, in which they appear to have aged much more rapidly than matched controls in a four-year period of time. So stress plays a really important role. You see it both immediately and long-term.

Andrew Huberman 11:15 I guess people rarely are sympathetic to presidents for aging quickly, because I guess if there were-

Dr. Teo Soleymani 11:21 Yeah.

Andrew Huberman 11:21 ... a president who did not age quickly, we would worry they did not work hard enough or something-

Dr. Teo Soleymani 11:26 Yeah. Yeah, yeah.

Andrew Huberman 11:26 ... of that sort.

Dr. Teo Soleymani 11:26 Yeah.

Andrew Huberman 11:27 But, um, the relationship between stress and skin fascinates me because not just of the direct relationship, like when we see people and they're stressed, like it seems like th- their whole... The pallor of their skin changes.

Dr. Teo Soleymani 11:40 Yeah. Yeah, yeah.

Andrew Huberman 11:41 Um, the kind of level of, of-

Dr. Teo Soleymani 11:43 Yeah.

Andrew Huberman 11:43 ... uh, gleam in their eyes change-

Dr. Teo Soleymani 11:45 For sure.

Andrew Huberman 11:45 ... and of course, the eyes are a direct, you know, piece of the nervous system, really. They're as close to the brain as one can get-

Dr. Teo Soleymani 11:50 Yeah, yeah.

Andrew Huberman 11:50 ... outside the skull.

Dr. Teo Soleymani 11:51 Yeah.

Andrew Huberman 11:52 But it also suggests...... because of the dynamic turnover of skin every 28 days, that if people were to become less stressed, that their skin health and appearance might improve. Is that also the case?

Dr. Teo Soleymani 12:04 For sure. It's why you see people have a glow after vacation, but you can't quantify that in a test tube or a lab. So in the immediate phase, there's a big shift in blood flow to the skin and when you're feeling, you know, very stressed out immediately, there's a fight or flight response that constricts the blood vessels in our skin to shuffle them to muscles and places where we need t- our body thinks we need to utilize them more. That's why when people are really stressed out, they may look pale or gaunt and that's the, we, we see that right away. Um, and then as, as that builds up over time, the health, the actual quality of our dermis and, and fat deteriorate from chronic stress changes, mainly due to cortisol and, and its sibling hormones and messaging systems in our skin. So for sure, I mean, stress is like something that is impossible to quantify in a lab measure, but very easily seen on exam, just looking at your skin, I can tell you've had a, either a rough day, if you didn't sleep well, you can see it in your skin and your eyes. So absolutely, I mean, that's why everybody likes to live a stress-free life and, um, we see changes and improvement in skin health when people move away from that stressor, whether it's a physical stressor, emotional stressor, psychosocial stressor, there is actual quantifiable improvements in skin health and that's pretty fascinating.

Andrew Huberman 13:23 It is fascinating. Uh, it also speaks to the value of having some immediate and long-term stress reduction techniques just as a sort of first principle-

Dr. Teo Soleymani 13:33 Yeah.

Andrew Huberman 13:33 ... of taking care of one's skin.

Dr. Teo Soleymani 13:35 For sure.

Andrew Huberman 13:35 There are some other things that cause vasoconstriction, the, uh, basically the tightening of the vessels and capillaries to the skin, as I understand. Maybe we could just, um, tick through a few of these and, and get your sense. Um, I consume caffeine every morning, usually yerba mate tea, some coffee a little bit later. Those will increase vasoconstriction to some extent, uh, although chronic caffeine intake may cause vasodilation. So I'd like to know the relationship between caffeine and blood flow to the skin and skin health and appearance. That's the first question. And then dovetailed with that question is nicotine, which is also thought to be a vasoconstrictor, it raises blood pressure, um, because it's a vasoconstrictor. What are the effects of caffeine, both acutely and chronically, and nicotine, let's assume that nicotine is consumed either by smoking or oral ingestion, um, on skin appearance and health?

Dr. Teo Soleymani 14:29 Uh, that's a good question. So caffeine is a known vasoconstrictor. Fortunately, when it's consumed in quantities that we have in coffee, tea and, you know, equivalent beverages, the amount that affects the tiny capillaries and arterials in our skin is minute and transient.

Andrew Huberman 14:46 Mm-hmm.

Dr. Teo Soleymani 14:47 So you may get a, a transient vasoconstriction with high caffeine intake, but usually there's a compensatory vasodilation as a result. Um, so the effects on skin are not as dramatic as people may make it seem. Now, one thing that we do see, and it's a little unclear as to why, is that people who have chronic high caffeine intake tend to produce more sebum in their skin, and it may be a result of vasoconstriction, may be a result of something that we don't understand that's compensatory as a result of those changes. So a lot of people who consume coffee may experience a little bit oilier skin. That being said, the data's equivocal as to whether or not caffeine has a deleterious, beneficial, or net neutral effect on the skin. I drink a lot of coffee. I haven't found that the vasoconstriction is something that's noticeable, but there are people who have different skin types, patients who have rosacea, for example, who are much more sensitive to those changes. They may notice that change in the color, in the vasoconstriction more with caffeine consumption.

Dr. Teo Soleymani 15:56 What used to be thought was that caffeine itself was a problem for flushing and redness and now we've realized it's actually not so much the caffeine because the concentration that reaches the skin is so minuscule, it's actually the temperature of the bever- beverages we drink. So hot beverages can affect the color of your skin, can make you flush more, make the redness more pronounced. Cold beverages tend not to have that effect. So it used to be an old adage in people who had like rosacea, for example, we'd say, "Don't drink coffee, don't drink tea." It's actually the temperature of the beverage, not so much the caffeine content.

Andrew Huberman 16:30 Interesting.

Andrew Huberman 16:31 And what about nicotine?

Dr. Teo Soleymani 16:33 So nicotine, great question. It is a known vasoconstrictor. Now, the concentration of nicotine when smoked is higher in the skin because of inhalational effects and the local effect of nicotine on our skin. So you do see a measurable vasoconstriction in the skin that becomes a problem, which is why patients who smoke age faster, patients who had surgery who smoke have a higher risk for poor wound outcomes, for poor healing because of that vasoconstriction. Usually people who, who use or consume nicotine aren't doing it once a week. Most people are using it daily or multiple times a day. So that chronic vasoconstriction adds up and has a net negative effect on the skin. So if you wanna keep your skin healthy, if you wanna look younger, I would refrain from nicotine use.

Andrew Huberman 17:25 What about vaping nicotine or oral use of nicotine? So nic-

Dr. Teo Soleymani 17:29 Yeah.

Andrew Huberman 17:29 ... nicotine gum, mints, pouches?

Dr. Teo Soleymani 17:31 Yeah. So-

Andrew Huberman 17:31 And, and let's tou- let's touch on vaping first because-

Dr. Teo Soleymani 17:33 Yeah.

Andrew Huberman 17:33 ... that's becoming more common.

Dr. Teo Soleymani 17:35 So with vaping we see the same problems in the skin. We don't know if it's, um, an inhalational issue or if it's actually the same concentration of nicotine that's reaching local skin causing the effect, but we see the same vasoconstriction when you match cigarette smoke with, with vaping if you have the same nicotine content.Now, for patches and gum, it's less of a problem and why that is, is the concentration of nicotine that reaches the skin is much lower. Usually when you chew it, it has to go through your digestive tract, then enter your bloodstream, then reach the surface of the skin. When you have a transdermal patch, it still goes through the bloodstream, then ends up in the skin. So because of how much it has to be processed, the concentration that reaches the skin is much lower. When we operate, when we do surgery, whe- any surgery of any kind, we try to transition people who smoke or vape to at least gums or patches to mitigate their withdrawal effect, but, um, you know, so they don't have the feelings but, you know, it doesn't have the same constrictive effects on their skin.

Andrew Huberman 18:37 What about alcohol?

Dr. Teo Soleymani 18:39 Yeah. Good question.

Andrew Huberman 18:40 You know, I did an episode of this podcast on alcohol which somewhat to my surprise, you know, uh, was very widely shared. Uh, only to my surprise because I've never been a big consumer of alcohol, um, but apparently many out there are and the data came back, at least to my understanding, that zero alcohol is healthier than any and that up to two drinks per week is probably okay as long as you're an adult-

Dr. Teo Soleymani 19:07 Yeah.

Andrew Huberman 19:07 ... of drinking age and not an alcoholic. You don't have issues with alcohol use disorder as it's now called. Probably okay but beyond that, you start running into some health issues that can be offset by better behaviors of other types. But what about the direct effects of alcohol on skin in the short term? Does it increase blood flow and therefore improve skin? Um, are there long term indirect effects? I could imagine that alcohol disrupts the gut microbiome which then disrupts skin, et cetera. So maybe we could break this down into direct acute effects, meaning immediate effects that are really direct from consuming alcohol that day, that week let's say, versus chronic effects through other systems like disruption of sleep and microbiome.

Dr. Teo Soleymani 19:50 Yeah. G- great question. Um, alcohol's, you know, alcohol and skin connection's complicated, convoluted, but generally thought to be a net negative, both short term and long term. So first, alcohol tends to be a mild diuretic, so it makes our body dispose of water at, a- a little bit more frequently. Um, what happens short term is that one, you get a- almost a m- mild diuretic effect from alcohol consumption which is why you tend to be thirsty in the middle of the night and wake up in the morning, tend to be parched. As a result, you see that diuretic effect on our skin. You see a little bit of hollowing in areas that you'd have normal volume and suppleness which is why they're, you know, people tend to see bags under their eyes or they look like they had a hangover, is from that mild diuretic effect. Also, as a compensatory mechanism, the skin produces a bit more sebum to compensate for that drying out effect. So, in the acute phase, your skin dries out, you'll look, look a little bit worse because of that diuretic effect. In patients who cannot or people who cannot tolerate alcohol, um, and there are genetics in Asian populations, in Southeast Asians that have a difficulty in breaking down acetaldehyde. That is an, a toxin that shows up in the skin and makes the skin vasodilate as a result. So that common college term that we used to hear, you know, the flush or the glow or, you know, incorrectly called the Asian glow is as a result of the inability to break down alcohol, and that usually you see immediately. People get a very bright red, uh, flush in their skin because of the acetaldehyde build up in the skin. Long term, one, the diuretic effect becomes a problem, so over time your skin's producing constantly more sebum to keep the skin supple, your skin is drying out, and as a result you run into things like breakouts and, you know, congested skin, you know, black heads, white heads, things like that. But long term alcohol use is also associated with lifestyle choices that may make your skin health worse. Generally speaking, when people are out binge drinking, they tend not to come home and do things that'll maintain their skin. Now, that's not a fixed rule but most of the time when you're out, you know, having a few beers or cocktails at the bar, you tend to come home and not do your diligent skincare routine or you may not be up, you know, with your hydration status or your dietary habits. So that's something we can't quantify easily but contributes significantly to faster aging, poorer skin health. Then the gut microbiome question. This is a great question because the data is widely variable for alcohol consumption and the effects or changes permanent or transient in the gut microbiome. There are some alcohol products like kombucha that has, uh, a higher alcohol concentration that's s- healthy for your gut. Then there's hard alcohols with a higher concentration that act as anesthetics and act as gut paralytics. So one of the things we see in people who consume a lot of high percentage alcohols is actually gut immobility and gut paralysis partly because of the anesthetic effect, partly because of the analgesic effect of alcohol, and also because it affects gut motility as a toxin. So generally speaking, gut m- the gut health depending on your consumption patterns, use, and concentration can be very deleterious. Some people are very sensitive and they have changes that reflect in the skin as a result of drinking a lot, and then there are some people who tolerate it more or maybe consuming things that are, um, healthier for the gut microbiome like things like, um, fermented alcohols like kombucha and things like that. So generally speaking, the higher the concentration the greater the, the problems. The higher the percentage of alcohol, the greater the problems. That includes the diuretic effect, that includes effects on the gut microbiome, that includes lifestyle habits. If you're drinking a lot of higher percentage alcohols you tend-... to feel the effects, you know, not just in the skin, cognitively, behavior wise, that can affect you. Whereas sometimes lower concentration alcohols, depending on the setting and lifestyle, may be net neutral, may be positive. Unclear on that part.

Andrew Huberman 24:17 But I'm not hearing any positive effects of alcohol on skin health or appearance.

Dr. Teo Soleymani 24:20 Generally not. Generally not.

Andrew Huberman 24:22 'Kay.

Dr. Teo Soleymani 24:22 Uh, uh, same as what we've seen with other organ systems, the brain, the liver, the skin reflects the same thing. If anything, it may be a net neutral. Most of the time it's a net negative.

Andrew Huberman 24:33 And what I'm pulling from all of the discussion we've had up until now is that improved blood flow and strong hydration status are both important. Do you recommend patients drink a certain amount of fluid each day or maintain adequate hydration as a means to build or maintain skin health and appearance?

Dr. Teo Soleymani 24:54 Great question. So that's, that's another common misconception that I see in that thinking drinking a lot of water will, or drinking a lot of fluids will directly affect the hydration status of their skin. And while there's a certain degree of truth to that if you're dehydrated, in that you need replenishment of fluid, you know, systemically, the s- every study that's looked at transepidermal water loss has not shown a great connection with regular, you know, fluid intake and water intake and skin hydration status. We find that that tends to be genetically defined and genetically encoded. Some people have drier skin, they need more methods to moisturize their skin. Some people have oilier skin and their sebum provides that moisturization. Now, if you're doing things, if you're active, if you're an athlete, if you're doing things in which you are dehydrated, then totally different story. But if you're living a more or less balanced life or a sedentary life and you're doing all the regular things, drinking a lot of water or fluids has not been shown to improve skin health. So that's why, generally speaking, most dermatologists will recommend some sort of moisturizer to replenish that. But you gotta know your skin. For example, m- my skin, I tend to be oilier. I don't usually need a moisturizer as much, whereas somebody who is drier will need some sort of barrier protection to allow, to minimize that transepidermal water loss.

Andrew Huberman 26:19 What are some of the, um, parameters for selecting a moisturizer? Um...

Dr. Teo Soleymani 26:24 Yeah. Yeah.

Andrew Huberman 26:25 You know-

Dr. Teo Soleymani 26:25 There's a lot of stuff-

Andrew Huberman 26:26 Like people are, people are immediately gonna, going to say, "Well, what, what constitutes a good moisturizer?"

Dr. Teo Soleymani 26:30 Yeah. Yeah.

Andrew Huberman 26:30 What should it have in it? What are some things to avoid?

Dr. Teo Soleymani 26:32 Yeah. It's a crazy market. There's a lot of things out there. I mean, you can Google skin snail moisturizer and you'll find people putting snail mucin on their skin-

Andrew Huberman 26:42 We-

Dr. Teo Soleymani 26:42 ... as a moisturizer.

Andrew Huberman 26:43 And you were telling me before this-

Dr. Teo Soleymani 26:44 Yeah. (laughs)

Andrew Huberman 26:44 ... uh, recording started, there are people who, uh, and forgive me for those that cringe when I say this, um, that put placental extract-

Dr. Teo Soleymani 26:52 Human placenta as a means of rejuvenating their skin health.

Andrew Huberman 26:56 Okay.

Dr. Teo Soleymani 26:57 I don't advocate it or don't say anything against it, but, um, I probably wouldn't recommend it. There's better, safer, more cost-effective ways of doing this. Simple things you wanna look for. One, is it non-comedogenic? That's a word you wanna look for for any moisturizer that's been tested not to clog your pores. That's a basic thing to look for where you won't cause another problem in trying to fix one problem. Number two, how oily or dry are you? Generally speaking, there are three flavors of moisturizers. There's ointments, there's creams, and there's lotions. Ointments are greasy. They're like petrolatum jelly or Vaseline based. Those are the best for moisturizing your skin, but they're greasy. Then there's creams, which are water emulsions with oil, um, suspended in it. And then there's lotions, which are generally powders that are resuspended with water. We, as dermatologists, tend to like the greasier the better. It provides the best barrier protection. But you have to know your skin. If you're somebody that is eczema-prone, you will need something that is an ointment that does better to protect the skin from drying out. If you're somebody that is acne prone, you won't tolerate greasy things. You'll break out more. So you wanna look for a lighter moisturizer that's non-comedogenic. So in a long story short, it's very s- you know, person to person specific. You gotta know your skin, but the fundamental things you wanna look for is, has this been tested to not, um, clog pores? And is it in a pump bottle or is it in a jar? Jars tend to be more occlusive. They tend to provide more moisturization, but they can lead to problems like acne breakouts. Whereas things in a pump bottle, because they're suspend- they're powders in suspension and they have to put alcohol in the product to allow it to come out of the pump mechanism, they tend to be lighter and not provide as m- as much moisturization.

Andrew Huberman 28:57 I see. So when I think about something in a jar, I think of something like, um, Aquaphor.

Dr. Teo Soleymani 29:01 Yeah. Yeah.

Andrew Huberman 29:02 Or something, which is pretty thick-

Dr. Teo Soleymani 29:03 Yeah. Yeah, greasy.

Andrew Huberman 29:04 ... thick stuff.

Dr. Teo Soleymani 29:05 Yeah. It's great-

Andrew Huberman 29:05 So that would be fine for someone with eczema, not okay for somebody with acne.

Dr. Teo Soleymani 29:10 Yeah, exactly, exactly. The greasier, the more occlusion it provides. But in doing so, it clogs everything. Now, if you're one that has some sort of skin issue in which you need that, it's the best thing. If you're one that is breaking out all the time, you want something lighter.

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Andrew Huberman 30:40 Why do people wake up with bags under their eyes if they just slept for six or eight hours?

Dr. Teo Soleymani 30:47 Yeah, well, maybe you need a little bit more sleep or maybe you had a wild night, I can't tell. But generally, the bags are caused by two things. One, fluid retention, so there's some lymphatic change that occurs under the eyes. That's most noticeable because the skin under our eyes and on the surface of our eyelids is the thinnest, so fluid changes are seen the quickest there. And as we're in a supine or prone position, fluid moves from our extremities back to our central ner- venous system, and it's easier to collect in the face, so we see it around the face. The other thing that we do notice with bags is just age-related fat herniation that shows up more, um, as we wake up because of positional changes. So if you've had, you know, um, a heavy meal the night before, something that has a high salt content, you're gonna retain a little bit more water, um, because of that solute shift. You may notice your eyes are puffier in the morning. Um, if you have allergies, uh, seasonal allergies, you know, um, asthma, eczema, they run in a family, that tends to make your skin retain a little bit more water as a result of that allergy response. And so people, you know, will notice springtime or fall time, they... Their eyes are swollen or their eyes are puffy, especially when their a-allergies are flaring. It's a, it's a product of water retention from all the histamine release and, and changes that occur in the skin.

Andrew Huberman 32:15 Skin cleansing is a topic that gets a lot of coverage.

Dr. Teo Soleymani 32:19 Yeah. Yeah.

Andrew Huberman 32:20 Um, and I sometimes get, um, chuckles or even attacks for saying, um, I've always just used unscented Dove soap, the bar, not the liquid soap-

Dr. Teo Soleymani 32:31 Yeah.

Andrew Huberman 32:31 ... or, like, a Cetaphil soap.

Dr. Teo Soleymani 32:32 Yeah.

Andrew Huberman 32:33 Um, and this is because when I was younger, like, much younger, I had very sensitive skin, when I was a, a kid, seven, eight, nine years old, and I think I just started using unscented Dove soap-

Dr. Teo Soleymani 32:43 Yeah.

Andrew Huberman 32:43 ... at some point and things like it, g- gentle-

Dr. Teo Soleymani 32:46 Yeah.

Andrew Huberman 32:46 ... you know? Uh, soaps without fragrances. What are your thoughts on, on those? And I ask not for my own purposes, I'm gonna stick with it because it works for me-

Dr. Teo Soleymani 32:56 Yeah.

Andrew Huberman 32:56 ... unless you tell me I shouldn't, but I see this enormous market for skin cleansers that includes a range of costs from relatively low to near astronomical.

Dr. Teo Soleymani 33:08 Yeah.

Andrew Huberman 33:09 And, um-

Dr. Teo Soleymani 33:10 Yeah.

Andrew Huberman 33:10 ... if you tell me that this, uh, unscented Dove soap or Cetaphil soap is the way to go, and by the way, I'm not sponsored by either of those. I don't even know who they're manufactured by.

Dr. Teo Soleymani 33:19 (laughs)

Andrew Huberman 33:19 So there's no commercial angle here. Um, but I'll be relieved because they tend to fall on the lower end of the cost bracket relative to some of these astronomically-

Dr. Teo Soleymani 33:28 Yeah. Yeah.

Andrew Huberman 33:28 ... priced, um, cleansers.

Dr. Teo Soleymani 33:30 Yeah. Skincare is a incredible multi-billion dollar market. That being said, there is not a shred of evidence that anything more expensive works better than anything cost-effective, so that's first and foremost. Number two, Dove white bar soap is amazing. It's what we recommend for newborns and kids with sensitive skin. Generally, when we say sensitive skin, especially in, in kids, toddlers, and adolescents, there's a component of some sort of eczema or atopic dermatitis that is not bad enough to have a diagnosis, but enough to say, you know, "I have sensitive skin." So, Dove white bar soap is what I use for my kids and I'm (laughs) not sponsored by anybody either, but I think it's an amazing, uh, product because it's safe, it's effective, it has the least amount of ingredients, no fragrances. These are all things that can irritate or cause an allergic response to skin that is sensitive, meaning your... Your skin mounts an en- re- immune response to some sort of environmental allergen or trigger. That's what we generally mean when we talk about sensitive skin. I personally use Cetaphil. That's my face, uh, wash. I have oily skin, I use the one that takes off more of the oil. So what you're looking for is defined by what bothers you or what your skin predicament is. What I do see is a problem, um, nowadays is particularly in the United States, we're a hyper-hygienic society. So what, what people tend to do is over-cleanse, and they over-cleanse for several reasons. One, because they are told that cleansing will fix their skin issue, or number two, they're told that some sort of organism is on their skin or some sort of bacteria that needs to be cleansed off to keep their skin healthy. Neither are true. The first thing you want in terms of a cleanser is something that's mild, fragrance-free, and has been tested to be hypoallergenic or non-comedogenic. That's first. Cetaphil, Dove, CeraVe, great, great stuff, um...... no association with any of them.

Andrew Huberman 35:35 The unscented, non-fragranced versions of them.

Dr. Teo Soleymani 35:38 Exactly, exactly. Um, that's first. Fragrances tend to be a, a problem for sensitive skin and patients who have atopic dermatitis or eczema. They tend to trigger allergic responses or exacerbations of their eczema flare, so we try to avoid fragrances by all means. Then, things that are gels or liquids tend to have preservatives in them to increase shelf stability, whereas bars tend not to. So if you are gonna pick something that is, uh, a gel, a liquid, look for one that's been tested by a dermatology group or verified by the American Academy of Dermatology, as one that is not, uh, allergenic or, um, has multiple preservatives, because that's another well-known but unidentified source of problems. Um, well-known to the dermatology world, not known to the lay, you know, the average person that the preservatives in our cleansers are a problem. Over-cleansing becomes really problematic in, in eradicating the skin microbiome. So what we see a lot of times are cleansers that are either, um, bactericidal, bacteriostatic, things like benzoyl peroxide, things like salicylic acid, things like certain astringent toners that are alcohol-based, and what they do is not only do they strip the normal oils from our skin that keep our skin supple and healthy, but they eradicate the normal host skin microbiome. Those are all the microorganisms that live on our skin, and we have trillions of them actively surveying our skin, living in, in normal symbiotic homeostasis, meaning they're our, they're our friends, they're living there for a reason, they don't cause any problems. But when you cleanse them off, you open up a, uh, an area for pathogens to take effect, and that's when we see a lot of problems, more so in industrialized countries. The United States is a notorious place for washing, especially after COVID. Wash, wash, wash, wash more, use a toner, wash some more, and that becomes really problematic because it sets up for organisms to take seed when they shouldn't be there. So overall, cleansing is great and the amount that you need to cleanse is based on how oily or sebaceous your skin is. The older you get, you may not need to cleanse as much. There are, you know, older patients don't need to cleanse their skin at all every day because they don't produce as much sebum or oil as younger patients, but everything should be defined by your skin's characteristics. So if you are one in which you notice, "By the end of the day, I'm, I'm oily. I'm breaking out," cleansing may be something that's beneficial for you to take off that excess sebum. If you're one that has dry skin, if you're one that had sensitive skin as a child, then over-cleansing is gonna be a problem, you're gonna wanna minimize that and, and keep that moisturization or that barrier protection going.

Andrew Huberman 38:39 So does that mean that people should bathe probably once or twice a day, but the people that are bathing three times a day, it's probably excessive? I mean, are we saying that you can't get into water? I mean, when you say-

Dr. Teo Soleymani 38:51 Yeah, yeah. Yeah.

Andrew Huberman 38:51 ... cleansing, you're talking about face cleansing. I realize this is going to be highly individual-

Dr. Teo Soleymani 38:54 Oh, yeah.

Andrew Huberman 38:55 ... but, you know, some people, um, are just out of habit, you know, shower and use cleanser, you know, twice a day.

Dr. Teo Soleymani 39:03 Yeah.

Andrew Huberman 39:03 Or once a day. I think, uh, for me, it's in the morning or in the evening, sometimes both. If I do a workout, I try and shower-

Dr. Teo Soleymani 39:10 Yeah.

Andrew Huberman 39:11 ... as close as possible after the workout, as soon as possible-

Dr. Teo Soleymani 39:14 Yeah, yeah.

Andrew Huberman 39:14 ... after the workout, rather, because, um, otherwise I will-

Dr. Teo Soleymani 39:17 Yeah.

Andrew Huberman 39:17 ... break out.

Dr. Teo Soleymani 39:18 Yeah.

Andrew Huberman 39:18 You know? So it sounds like one has to kind of learn what their-

Dr. Teo Soleymani 39:21 Yeah.

Andrew Huberman 39:21 ... cadence is, and that's going to vary by age.

Dr. Teo Soleymani 39:23 Yeah.

Andrew Huberman 39:24 Um...

Dr. Teo Soleymani 39:25 There's a lot of factors to this. I, I, I think Ashton Kut- Kutcher and Mila Kunis famously said they shower I think once a week or something like that, and it stirred up a lot of conversation when that came out. Truth be told, you don't have to cleanse every day if your skin is otherwise fine and healthy and you're not bothered by anything-

Andrew Huberman 39:45 Mm-hmm.

Dr. Teo Soleymani 39:47 ... you live a lifestyle in which you're not sweating excessively or producing a lot of sebum. I myself, same thing, I work out, so I l- I shower after working out, and I usually shower before I get into bed, because after a long day of work, I tend to have, you know, things on my skin that shouldn't be there. That's only fitting for me, because if I don't, I tend to have problems, I tend to break out, I tend to have things that, you know, shouldn't happen because of my hygiene habits. That said, m- there is no indication or no medical necessity to have to cleanse your skin even once a day. Oftentimes, older patients cleanse or shower once a week and they're totally fine, but it'll have to be defined by your skin and what problems or ailments are specific to you. Generally, if you work out, if you let sweat dry on your skin, it causes several problems. Number one is irritation itself from the salts that crystallize from the sweat drying off. Number two, the sweat itself is a source of food for certain yeast that are normal symbiotic yeast that live on our skin, so it contributes to things like dandruff, um, what we call tinea versicolor, which is a type of yeast that grows on our skin. So generally, if you work out, try to wash those, you know, things off. Also, if you are one of, you know, acne-prone skin, if you're an adolescent, if you're a teenager, if you're an adult dealing with acne, the sebum that your body's producing is food for the bacteria that cause this, so you tend to want to clean some of that excess sebum off. Those are simple indications to cleanse both your face and your body, but if you're not having any problems, you actually don't need to do any of that. In Europe, they shower and cleanse at a fraction of the frequency that we do in the United States, and when you look at incidences of the most common skin conditions, they're the same.

Andrew Huberman 41:42 ... including things like acne, psoriasis-

Dr. Teo Soleymani 41:45 Yeah. Yeah.

Andrew Huberman 41:46 You know, most people think about shampooing for sake of hair-

Dr. Teo Soleymani 41:49 Yeah.

Andrew Huberman 41:49 ... but there's the scalp component-

Dr. Teo Soleymani 41:51 Yeah.

Andrew Huberman 41:51 ... and since you're an expert in skin-

Dr. Teo Soleymani 41:53 (clears throat)

Andrew Huberman 41:53 ... we should probably, uh, spend a bit of time on this. Um,

Andrew Huberman 41:57 for people that tend to have a dry or flaky scalp, uh, what should they do about that? My understanding is that some of the more, um, typical commercial anti-dandruff shampoos can contain things that might cause issues for hair itself, so they might help with the flaking and drying of the scalp, but damage other aspects of, you know, either appearance or health of hair.

Dr. Teo Soleymani 42:19 Yeah.

Andrew Huberman 42:19 Um, what are some really good options for people that have dry scalp? What are some great options for people that have oily scalp?

Dr. Teo Soleymani 42:27 Yeah.

Andrew Huberman 42:27 Um, and let's leave aside the frequency of use-

Dr. Teo Soleymani 42:30 Yeah, yeah.

Andrew Huberman 42:30 ... and just, um, perhaps just put it on the shelf as, uh, as much as you need it, but not more.

Dr. Teo Soleymani 42:35 Sure.

Andrew Huberman 42:35 So that could be once a week, it could be daily-

Dr. Teo Soleymani 42:36 Yeah.

Andrew Huberman 42:37 ... it could be twice a day if... in extreme cases, it sounds like.

Dr. Teo Soleymani 42:39 (sighs) So when we think about the scalp, when we think about dry or flaky scalp, we think about two main conditions, either seborrheic dermatitis, which is medical grade dandruff, or... Or the medical name for dandruff, or psoriasis. They are two different entities, but they generally contribute to the same problem, which is redness, flaking, and dryness of the scalp. Now, it's important to note that the hair on your head is dead. It's not alive. The only area that's alive is two and a half millimeters in the skin. So the hair that we see on our scalp is not a living entity, so there's a common misconception that you can affect the health or quality of your hair by putting things on the hair, and I'll go into that in just a, just a minute. Um, but the hair itself that you see is, is not living. The only area that's living are the stem cells in the papilla of the hair and in the bulge region of the hair, which reside in the skin. So nothing that you put on your scalp will make you lose your hair, will make you grow new hair, for the most part. Um, why that's important. When we treat dry or flaky scalp, we treat it with several things. Th- the most common cause is an overgrowth of yeast from the sweat and oil that is produced from our h- our scalp, and that's seborrheic dermatitis. That's m- the medical name for dandruff. And so we treat it by, one, lowering the amount of that yeast that's living, and that's usually with, uh, shampoos, um, that are prescription or over-the-counter. You know, things like zinc or ketoconazole shampoos are very common things, and then the other thing that we do is to dampen the immune response to this overgrowth of yeast. So the reason our skin flakes and gets red and proliferates is our immune system's responding to something. It's either responding to the yeast, or it's responding to itself, which is what psoriasis is. It's an immune-mediated over-proliferation of skin cells because the immune system is overactive in the skin, and the way we treat that is just topicals or certain medications that suppress the skin's immune system or immune activity. None of that affect the actual hair itself. What does happen is shampoos tend to have things that strip oils as a mechanism of cleaning. So when you take a cross-section of the hair, there are seven layers, and the, the layer that provides that color, sheen, and structure is called the cuticle. As we age, we lose the cuticle, and that's, that's a common problem what we see in male and female pattern hair loss, or androgenetic alopecia, is we lose that cuticle, which makes us lose the shine and the structure and the strength of our hair. Our body tries to replenish that with the oils, so when people wash their hair, sometimes they feel like their hair becomes more limp or dull or lifeless. It's because we've taken that artificial oil coating, uh, that replaced the cuticle and, and washed it off. So good news is you're not gonna do any harm putting any of the pr- topicals on your scalp. Bad news is you probably won't bring a lot of it back to life either. But when we treat flakiness, you know, redness, things like that, we're treating two entities, usually with topicals and because we're either trying to treat over-proliferation of something or trying to calm down the skin's immune system.

Andrew Huberman 46:08 Got

Andrew Huberman 46:09 it. So it sounds like the best options for cleansing skin, for shampooing, really stem from knowing whether or not your skin tends to err oily or dry-

Dr. Teo Soleymani 46:21 Yeah.

Andrew Huberman 46:21 ... figuring out how often to cleanse, and then as you pointed out before, even though there's an enormous range of cost for these things-

Dr. Teo Soleymani 46:28 Yeah.

Andrew Huberman 46:28 ... none of the solutions that you're describing sound like they fall on the high end of cost, or even in the middle end of cost, which is a bit surprising to me.

Dr. Teo Soleymani 46:36 Yeah.

Andrew Huberman 46:36 This might be one of the few areas where, you know, like, if I had a magic wand, I would make for all, uh, you know, organic, uh, non-processed and minimally processed foods to be very inexpensive-

Dr. Teo Soleymani 46:50 Yeah.

Andrew Huberman 46:50 ... but it turns out those things tend to be more expensive. You can go to farmer's markets and cut back on the cost, et cetera, but there seems to be, um, an unfortunate trade-off between availability and cost and benefit-

Dr. Teo Soleymani 47:02 Yeah.

Andrew Huberman 47:02 ... or at least risk. But it doesn't sound like that's the case with skincare or scalp care, that one can, uh, exercise really excellent skin and scalp care without having to go into a range of, of spending an outrageous amount of money.

Dr. Teo Soleymani 47:15 No. I think, one, you're absolutely right. There isn't... The more expensive does not mean better. In fact, they sometimes become more problematic because there's more ingredients in the more expensive products, including elegant fragrances and stuff like that, which can be problematic. That's number one. The second thing to note is that generally speaking, there is some connection between skin health, skincare, and this realm of beauty, which people overlap a lot in, and there... When we trend into this realm of beauty, glamour, et cetera...... price and objectivity are taken out. And that's why you see a lot of skincare products that are so expensive because they draw towards another level of desire that's not just medical, it's aesthetic. And that's where you'll find creams that are $200, $300 for a little amount of cream that does the same thing that your jar of petrolatum or Vaseline or Aquaphor does. That part is really hard to mitigate, but in general, almost everything that we as dermatologists and skin cancer surgeons and, um, experts in the field recommend are really cheap, cost-effective, and they have the least amount of ingredients in them, and that's what I would recommend. That's what I recommend for my family and for my patients. You don't have to spend a lot to have excellent skincare, and you don't need to have it be a multi-step routine. Oftentimes, people overdo it. You know, the more steps that there are, there's more chances that something your skin will respond to negatively, the more chances you are to have a bad outcome to an ingredient of a product you're putting on your skin. So keep it simple, keep it cheap, and you'll do great.

Andrew Huberman 48:58 It's going to be very reassuring-

Dr. Teo Soleymani 48:59 (laughs) Yeah.

Andrew Huberman 49:00 ... to many people. It's also going to be, um, uh, somewhat, uh, destabilizing to people-

Dr. Teo Soleymani 49:05 Yeah.

Andrew Huberman 49:05 ... who are really attached to the idea that the more expensive products are really doing something that much more beneficial for them.

Dr. Teo Soleymani 49:11 Yeah, not much at all. Not, not anything. And another important thing to, to consider when looking at skincare, skin health, and then trending into that area of aesthetics and beauty is that most active ingredients, if they're really active, tend to be controlled by the FDA. So most things that are sold over the counter have actives that are not at a concentration high enough to be considered therapeutic because that's when you get into the definition of a drug. So looking at things like anti-dandruff shampoos, you know, anti-aging creams, you know, um, acne medications, they work a little bit. If they worked perfectly, then most medical dermatologists would be out of a lot of patients and we see a lot of skin disease that still continues because the active ingredients aren't at a concentration high enough to provide therapeutic benefit.

Andrew Huberman 50:11 Mm-hmm.

Dr. Teo Soleymani 50:11 So save your money. If you really need something to change some part of your skin, see a good dermatologist, see an expert, and see what they can come up with.

Andrew Huberman 50:20 So this seems like an appropriate time to ask about sun exposure, and then we'll also talk about sunscreen, sunblocks, skin cancer.

Dr. Teo Soleymani 50:27 Sure.

Andrew Huberman 50:28 But what is the relationship between sun exposure and skin health specifically? Meaning, how much sun exposure is healthy for our skin? I'm a big believer in getting sun exposure to the eyes early in the day, blinking as needed to protect the eyes, of course, but in order to set one's circadian rhythm for elevated daytime mood, focus and alertness, and improved nighttime sleep. There's just so much data to support setting one's circadian rhythm properly for sake of health, and there's so much data to support the fact that sunlight viewing, in particular, is the best way to do that, and sunlight viewing in the early part of the day, in particular, is the best way to do that. But beyond that, how much sun exposure to the skin is good for us? Is it zero? Is it five minutes? Does it depend?

Dr. Teo Soleymani 51:21 Great, like, great controversial question, and it depends on which school of thought or camp you belong in. As a skin cancer surgeon and a, somebody who's developed a reputation for seeing some of the worst, most complicated and life-threatening skin cancers in, in Los Angeles, obviously I see some of the consequences of long-term sun exposure and chronic, chronic photoaging. That being said, I absolutely think that getting sun is healthy for us. Now, why? The studies that talk about vitamin D, and we'll touch on vitamin D as its own entity and then overall health as another entity, but most of the studies that look at vitamin D synthesis from UV exposure on the skin suggest that you only need about 15 minutes, and that you don't need a broad, uh, surface area of exposure. You can get enough vitamin D formation with just about 15 to 20 minutes of sun on your forearms. So there's a whole school of thought by a lot of experts who think there's no amount of UV exposure that's healthy for the skin, and I tend to be on the other camp for several reasons. One, there is a component of feel goodness, if that's a word, from being in the sun that affects overall skin and physical biology. When you're out in a sunny day, you tend to be less stressed. You tend to be a little happier. Now, it's, it's a generalization, but most of the time when you get outdoors, you get outside, and it's a nice sunny day, you feel better. And although you can't quantify that feeling better, there are some parameters that can be measured. Decreases in cortisol response, improvements in skin appearance and texture. Um, the other important thing about being out in the sun is finding out your own tolerance, right? So I have a little bit more olive skin, and I can tolerate the sun a little bit longer than somebody who has fairer and lighter eyes. In my opinion, I don't think, and in most of the evidence, there isn't a finite amount of time because that time is dictated by your skin's ability to tolerate the UV, but I absolutely do not think that sun avoidance is a healthy thing. And this is coming from somebody who operates on head and neck skin cancers literally every day. I think there is a component of sun exposure that's not just for vitamin D synthesis, but something that improves your overall wellness that is-... uh, visible and maybe not laboratory measurable, but, um, you definitely are healthier when you're feeling better and you're happier. I lived on the East Coast in places w- that had lower, uh, days of sun, and I had seasonal affective disorder. It bothered me. My mood was lower. I felt not as healthy, you know. I'd come home, my family would say, "Hey, you look sick." And it just... You know, I wasn't sick. I hadn't had any sun. I was lighter than I was and my family (laughs) interpreted that as not being healthy. You know, my wife, on the other hand, didn't. She didn't mind the grayness. So, there is a timeline for biologic processes, like vitamin D formation, that's helpful. People can argue that you can get it through supplementation and food, and that's, that's correct. But there is a component of sun exposure that makes you feel better overall and provides some sort of wellness that you may not be able to quantify, but you see in appearance and in discussion in longevity. So, absolutely, I think you should be out in the sun. I don't think you should burn and I don't think you should be out long enough where your skin starts to turn red. That's the first sign that you're reaching kind of critical mass in terms of UV exposure. But I absolutely think the sun is a good thing for us.

Andrew Huberman 55:10 So even midday sun, you know, maybe if there's some cloud cover or if we have some sunscreen on or a physical barrier, like sun and long s- uh, excuse me, like hat and long sleeves, then getting some sun exposure, in your mind, is good for our overall well-being, mood, et cetera?

Dr. Teo Soleymani 55:29 Yeah, I think, uh, you know, I mean, midday sun has a higher UV index, so you're more likely to burn and have a problem with prolonged exposure. But yeah, absolutely. I think, you know, there's been numerous studies that, that have looked at people who go out for a walk in, you know, busy urban cities and work environments. If they go out for a walk in the sun, they feel better, their stress responses are lower, their questionnaires in responding to life stressors and day-to-day stressors are decreased. There's a lot of studies that look at being outside as a measure of well-being, mental health. Well-being, um, uh, is improved with outdoor sun exposure. So there's a lot of that. Now, can I quantify it in the skin? Hard to say. One thing we do know is that obviously too much sun exposure, like anything, too much of a good thing can be a bad thing. But I really do think that being out in the sun for the amount that your skin can tolerate is a good thing.

Andrew Huberman 56:24 I'd like to take a brief break to thank one of our sponsors, LMNT. LMNT is an electrolyte drink that has everything you need and nothing you don't. That means the electrolytes sodium, magnesium, and potassium in the correct ratios, but no sugar. Now, I and others on the podcast have talked a lot about the critical importance of hydration for proper brain and bodily function. Research shows that even a slight degree of dehydration can really diminish cognitive and physical performance. It's also important that you get adequate electrolytes in order for your body and brain to function at their best. The electrolytes sodium, magnesium, and potassium are critical for the functioning of all the cells in your body, especially your neurons, or nerve cells. To make sure that I'm getting proper amounts of hydration and electrolytes, I dissolve one packet of LMNT in about 16 to 32 ounces of water when I wake up in the morning, and I drink that basically first thing in the morning. I also drink LMNT dissolved in water during any kind of physical exercise I'm doing, especially on hot days if I'm sweating a lot and losing water and electrolytes. If you'd like to try LMNT, you can go to drinklmnt.com/huberman, spelled drink L-M-N-T dot com slash Huberman, to claim a free LMNT sample pack with the purchase of any LMNT drink mix. Again, that's drinklmnt.com/huberman to claim a free sample

Andrew Huberman 57:35 pack. What about sunscreens and sunblocks? And I think, uh, we should distinguish between those two labels.

Dr. Teo Soleymani 57:42 Yeah. Yeah.

Andrew Huberman 57:43 Um, you know, in, in the old days, as I understand, sunscreen was the word used to describe stuff that you put on your skin that absorbs UV, and then sunblock was the stuff that you put on your skin to reflect UV.

Dr. Teo Soleymani 57:57 Yeah.

Andrew Huberman 57:57 Um, typically, nowadays, people say sunscreen more than they say sunblock or they use them interchangeably without any knowledge of the underlying mechanism.

Dr. Teo Soleymani 58:05 Yeah.

Andrew Huberman 58:06 Um, so first of all, let's clarify sunscreen versus sunblock.

Dr. Teo Soleymani 58:10 Yeah. So, a lot of the nomenclature, data, understanding, chemicals, um, things that were considered okay to be used came from an original FDA 1999 manuscript. (inhales deeply) And that data hadn't changed for almost 20-something years. And more recently, in 2021, the FDA released a proposed final order for the term "sunscreens" as a whole. Now, when we talk about sunscreens, sunscreens are considered an over-the-counter, non-prescription drug. So they're regulated tightly by the FDA. They're in the same category as any over-the-counter drug. So, before this, this decision ruling, there was a lot of nomenclature, wording confusion. Sunblock seemed better than sunscreen, suntan, um, suntan oil. All of that's been changed recently or has been proposed to get rid of to unify the field and make it very clear what the goal is. So no longer do we use the term sunblock, although in the past, that had been used for things like zinc or zinc and titanium-based creams, like the old 1980s or 1990s white lifeguard noses, if you remember. That used to be thought as sunblock, whereas less, less, um, protective chemicals were used as sunscreen. Now that's changing, and the FDA 2021 proposed order says we n- need to unify everything and call it a sunscreen. Now, sunscreens, being regulated drugs, take a lot of scrutiny for many reasons. They take scrutiny from the FDA in terms of proving efficacy and safety. They take a lot of scrutiny in society for being dangerous or not dangerous, effective or not effective, causing downstream effect or not causing downstream effect.So that's been a big point of contention in terms of the population, the American Academy's stance, dermatologists' stance, and then the skin cancer patients' beliefs, the beauty experts' beliefs, and average persons' opinions. Um, sunscreens generally fall into creams, lotions, topical products that protect the skin against sunburn. We used to be able to suggest that they reduced the risk of skin cancer, um, prevented premature aging, but that can be a little convoluted and the FDA is rewording that into not being able to say that anymore in their proposed order. But what sunscreen's intention is, is to protect the skin against excess UV exposure. And they come in two flavors. They come in mineral-based sunscreens, which tend to be in the category of zinc and titanium minerals, and they tend to be chemical sunscreens, which are a bunch of different chemicals.

Andrew Huberman 1:01:09 Mineral-based sun- sunscreens are sometimes called inorganic, correct?

Dr. Teo Soleymani 1:01:12 Yeah. Inorganic or physical sunscreens, whereas the chemicals are considered organic or chemical sunscreens. Totally right.

Andrew Huberman 1:01:20 Is the mechanism for these two the same? Because, um, I was under the impression that the mineral-based inorganic sunscreens, um, reflected back UV rays, um, whereas the chemical-based sunscreens absorbed UV rays. But there's a bit of a online debate-

Dr. Teo Soleymani 1:01:39 Yeah. There's-

Andrew Huberman 1:01:39 ... about this, um, claiming that they all absorb UV rays.

Dr. Teo Soleymani 1:01:43 Yeah. So historically, it had been thought that mineral or physical sunscreen, zinc, zinc and titanium sunscreens, worked by basically acting as a metal reflecting shield. And for the most part, that thinking is n- not incorrect. There's, uh, there was a new study that showed that they work by actually absorbing them, um, but not having any sort of chemical change. So the way chemical or organic sunscreens work is they absorb the ultraviolet radiation, they undergo a chemical reaction to reduce its energy and dissipate that energy as heat. So chemical sunscreens work by actually absorbing it and undergoing a change, whereas mineral or physical sunscreens don't do that. I still think of them simply as minerals basically shield the skin like armor, whereas chemicals act as a sink and undergo a change to reduce that energy. So that's kind of the simplistic way that sunscreen, topical sunscreens work.

Andrew Huberman 1:02:45 So what is your recommendation about protecting oneself from the sun? And maybe for the moment, let's just set aside sunscreens and acknowledge that a physical barrier like hat, long sleeves, long pants provides a pretty good barrier to the sun. Correct?

Dr. Teo Soleymani 1:03:00 Yeah.

Andrew Huberman 1:03:00 Okay.

Dr. Teo Soleymani 1:03:00 In fact, physical barriers like shade, clothing, hats have been shown to be more effective, um, than topical sunscreens for several reasons. But there are many ways to protect your skin, and you have to ask why you're protecting your skin. So is it because you're worried about premature aging, uh, photo damage and things like of that nature? Are you worried about your risk for skin cancer? Um, do you have a sun-sensitive skin condition like lupus or PMLE that is sensitive to UV exposure? So the first question is, well, why are you worried or why are you taking protection? And then you customize your approach to that. Now sunscreen, topical sunscreens are not the only form. By and large, there, there are many other forms, both physical blockers and certain things in the supplement, uh, world that can protect your skin. For example, I myself take a product called Sun Powder that provides an internal sun shield and allows me to be in the sun longer, um, without the need to reapply or if I can't reapply. But, you know, f- by and large, the best way to protect your skin is some sort of shield, whether it's clothing, hat, or some sort of cream that you put on. Now, for patients who are worri- or for people who are worried about premature aging, they don't have a strong family history of skin cancer, they've never had one before themselves, then the approach to that is a little bit different than people who are worried about skin cancer development, fam- strong family history of skin cancer, they're worried about, you know, losing a part of their ear or, or, uh, part of their nose to skin cancer development. And that's very different from medical conditions that are very sun sensitive. By and large, the patients who have medical conditions that are sun sensitive, the large one being lupus, for example, need the most sun protection because they're so inherently sensitive to UV exposure. Something that's very interesting, we know without a doubt that every common skin cancer, there's many, many skin cancer types, but the three most common are, you know, basal cell carcinoma, squamous cell carcinoma, and melanoma. Those are the three most common ones we see. They have all been shown to have UV mutation signatures when we sequence the tumors. However, in every single clinical trial, in every single randomized trial that looked at topical sunscreens as a means of reducing risk, there has not been a single study that showed any sort of risk reduction in the development of the most common skin cancer, which is basal cell carcinoma. One in four Americans will develop this. Also, there hasn't been a single study to date that showed that diligent sunscreen use, topical sunscreens, will reduce disease-specific death or dying from skin cancer. So if you think every skin cancer is sun-driven, there are UV mutation profiles in these tumors, then by using sunscreen should reduce that, right?... and it's not that clear. We don't understand fully the drivers of this. So, why I bring this up and why we talk about sunscreens and barriers to blockade first, sunscreens, topical sunscreens are not the only form. You know, in fact, clothing and shields, you know, shade and hat are, uh, in my opinion, better, and a lot of studies suggest that they're better. There are oral supplements that can also protect your skin from burning and, and reduce your skin cancer risk. And number three, not everything is sun driven. We do know that diligent sunscreen use decreases the incidence or the amount of melanoma formation and squamous cell formation, but we still don't know whether that reduction has changed the number of patients dying from that. We also know that it has no bearing in the development of the most common skin cancer, which is basal cell. So, we go back to the drawing board and scratch our heads saying, "Hey, what is the trigger?" You know, the genetics loads the gun, for example, and maybe even pulls the hammer, but what in the environment is the trigger? Is it strictly UV? Is it some other culprit? So, sunscreens are a really hotly debated topic. So many things to talk about in, in terms of sunscreen.

Andrew Huberman 1:07:27 So, if I understand correctly, you're saying that the use of sunscreen can protect against premature aging. Let's say sunblock, because I think we're going to arrive at mineral-based sunscreens-

Dr. Teo Soleymani 1:07:38 For sure. Sure.

Andrew Huberman 1:07:38 ... probably being the better option, but we can, uh, make sure that we double-click on that, so to speak. But that sun exposure itself perhaps is not linked to the most deadly of skin cancers. That tells me two things. It doesn't tell me that I can just spend as much time as I want in the sun, but it does tell me that I should probably look into the things that cause the most deadly skin cancers.

Dr. Teo Soleymani 1:08:03 Yeah.

Andrew Huberman 1:08:03 Okay. But I'm also hearing that regular application of sunblock and/or physical barrier will protect my skin against some forms of premature aging caused by sun exposure, but will not necessarily protect me against the most common forms of skin cancer. That is peculiar, uh, in the sense that, or even baffling, um, to the, you know, non-dermatologist, me, um, because we already know that sun exposure causes UV mutations, mutations in the DNA of cells is one of the kind of core components of cancers. So, how do we square all of this?

Dr. Teo Soleymani 1:08:42 Hm. Great question, and the more we dive into this and the more experts we, we look at and the more data we, we collect, the more we're scratching our head as to we don't know and why this occurs. Now, I am not saying don't use sunscreen (laughs) . Let's just let that be known. I, I think sunscreens are excellent forms to protect against premature photoaging and signs of sun damage. I think sunscreens help reduce the incidence of common garden variety skin cancers. But they are not the only form of protection, and they seem to not be as important or have as much effect in reducing the incidence of our most common skin cancer, which is basal cell carcinoma. Moreover, I would say, and the data unfortunately shows, that the majority of skin cancers that we see that end up hurting people or, or killing patients don't arise in chronic sun exposed areas to begin with. You know, I have a 27-year-old patient right now dying of a metastatic melanoma that arose in completely sun-protected skin. I have a 56-year-old mechanic right now who's dying of a squamous cell carcinoma that arose from the back of his ear. And most experts who have this type of, type of experience dealing with these patients have the same observation. So, the question is, what's pulling the trigger? For the most part, UV plays a big role. The, the mechanism in which cancer forms, if we believe this, the basic high school biology is, you know, hyperplasia, metaplasia, dysplasia, carcinoma. So, there's a, a trajectory of changes that are occurring as a result of cumulative mutations in the skin. If we believe that trajectory, then every skin cancer should see that, um, change, and we just don't see that. Also, we know that skin cancers that arise in sun-damaged skin behave differently than the ones that are very lethal. So, why I bring this up, I, I think sunscreen is very helpful, but we have this unfortunate trend in medicine, particularly in dermatology, to guilt people into f- thinking that they cause this to themselves, and I don't think that's right nor okay, and I, I don't like that, because they make it seem that, "Oh, the sun you got in 1987, that one sunburn in Hawaii, did it to you." And that's absolutely not the case. There are many things at play, fundamentally your genetics and immune system, that play a huge role in skin cancer development that sunscreen cannot address and will not address. Now, the, the wild card is, "Okay, what are my genetics?" And that's the part we don't know, which is why dermatologists say, "Okay, let's at least control the thing that we can, which is UV exposure." But I bring this up because p- you know, don't feel bad about getting some sun, and don't feel guilted into something that if, if something bad occurs, it's not your fault. Some of it is out of your control, and that, that's really important, 'cause I see a lot of very bad skin cancers in my practice, and I, I hate this feeling of patients feeling, feeling like they did it to themselves.

Andrew Huberman 1:12:05 I think most people would prefer not to have the premature aging caused by sun exposure.

Dr. Teo Soleymani 1:12:08 Yeah.

Andrew Huberman 1:12:09 So-

Dr. Teo Soleymani 1:12:10 Yeah.

Andrew Huberman 1:12:11 ... what should those people do?

Dr. Teo Soleymani 1:12:12 Yeah.

Andrew Huberman 1:12:12 Um, I've taken on a practice of...... putting a mineral-based inorganic sunscreen on my face, my arms if they're going to be exposed, back of my neck, tops of my ears, if I'm going to be out in mid-day or late-day sun that feels intense, and I'll do that every single time I go out now.

Dr. Teo Soleymani 1:12:34 Yeah.

Andrew Huberman 1:12:34 Um, on overcast days, not so much.

Dr. Teo Soleymani 1:12:36 Okay.

Andrew Huberman 1:12:37 Uh, for viewing morning sunlight, I don't do that. In fact, when the sun is low in the sky, I don't tend to wear sunblock. That's me.

Dr. Teo Soleymani 1:12:44 Yeah.

Andrew Huberman 1:12:44 That's been my choice.

Dr. Teo Soleymani 1:12:46 Yeah.

Andrew Huberman 1:12:46 It, um... There were a few years there where I didn't put on sunscreen or if I did, it was, like, on a camping trip or skiing or something where the sun felt very intense, and in that case, I would just reach for whatever sunscreen or sunblock was available because I wasn't aware that some of the ingredients in certain chemical-based sunscreens may be problematic.

Dr. Teo Soleymani 1:13:05 Yeah, yeah.

Andrew Huberman 1:13:05 So, um, I think I fall into the typical category of a lot of people-

Dr. Teo Soleymani 1:13:10 Yeah.

Andrew Huberman 1:13:10 ... um, but of course, there's the category of people that are like, "Nope, sunscreen, sunblock is terrible all the time," or they're just too lazy or uninterested in applying it. But then there's this whole category of people that are putting it on every single time they go outside-

Dr. Teo Soleymani 1:13:25 Yeah. Yeah.

Andrew Huberman 1:13:25 ... in hopes that that's going to keep their skin much, appearing much younger-

Dr. Teo Soleymani 1:13:29 Yeah.

Andrew Huberman 1:13:29 ... and just generally are kind of afraid of the sun.

Dr. Teo Soleymani 1:13:32 A lot of good points. So, there's that famous New England Journal of Medicine picture of the truck driver that got chronic sun exposure on the left side of his face and you see all this wrinkling and mottling of the skin on the left side and nothing on the right side.

Andrew Huberman 1:13:45 Mm-hmm.

Dr. Teo Soleymani 1:13:46 So by absolute measure, sun protection or UV protection will reduce premature aging. Now interestingly, that guy did not develop anything in that area, so again, it goes back to, well, what's pulling-

Andrew Huberman 1:13:57 No skin cancers.

Dr. Teo Soleymani 1:13:59 No. So the question is, what's pulling the trigger? Is it truly UV or is there something else we're missing?

Andrew Huberman 1:14:03 If you tell me that he got skin cancer on the opposite side, I'm really gonna gasp.

Dr. Teo Soleymani 1:14:07 (laughs)

Andrew Huberman 1:14:07 But no.

Dr. Teo Soleymani 1:14:08 I, I, I ha-... I don't know if he's had any on the opposite side, but in that photo, it's purely, uh, premature aging. So things that you wanna do. Obviously, you know, don't let your skin turn red. Take some sort of-

Andrew Huberman 1:14:19 Mm-hmm.

Dr. Teo Soleymani 1:14:19 ... some form of barrier protection, whether it's a sunscreen, uh, supplement like polypodium, something that protects your skin from the inside out. And skin changes are cumulative, s-, um, so what we can tolerate in our teens and 20s is very different than what we can tolerate in our 40s, 50s, and 60s because there's a cumulative mutation profile burden that we see. Interestingly, there was an eyelid study that was published recently that looked at eyelid skin that was removed during, you know, cosmetic surgery, upper eyelid lifts, that was otherwise discarded, and when they ran genetic sequencing on normal eyelid skin, they saw the same mutations that they would see in matched skin cancers.

Andrew Huberman 1:15:03 Hm.

Dr. Teo Soleymani 1:15:03 But the eyelids didn't have any skin cancer. So, we know UV triggers these mutations and we know UV degrades collagen and elastin. It thins blood vessel walls as a mechanism of, um, of its effects on the dermis. The data is equivocal as to how those mutations trigger skin cancer formation, but in terms of premature aging, absolutely. So you wanna take some form of protection. Now, what type of protection do you take? Depends on your genetics, how much you can tolerate, and what your family lineage looks like. Some people have the genetics of early aging. It's part of their skin biology and you can't change that, but you can mitigate that risk with more strict UV avoidance.

Andrew Huberman 1:15:47 Mm-hmm.

Dr. Teo Soleymani 1:15:47 Some people, you know, they look young longer, you know, some family lineages just have great genetics in their skin, they can tolerate a little bit more sun. In terms of physical sunscreens versus chemical sunscreens, that's a hotly debated topic. In my personal practice and for my family, I tend to only recommend, uh, mineral zinc or zinc and titanium sunscreens for several reasons. In the original set of sunscreens that were approved by the FDA that came out in 1999, there wasn't enough data to look at biologic effects, efficacy, internal organ involvement, et cetera. Fast-forward 20 years and we've gathered a lot more information about these chemical organic compounds. There is an amazing 2020 study that looked at absorption of chemical sunscreens when they're applied onto the skin. They looked at absorption with single application and they looked at absorption over four days of application. Now, in this study, they applied a little bit more than th- you know, r- real world, uh, experience would, but even with single application, they saw blood plasma absorption of these chemicals that were 100 to 500 times greater than the upper threshold defined by the FDA. Now, the question exists, okay, what does that mean? Is this healthy? Is this not healthy? Is it neither? That's still up for debate, but in looking at the more recent literature and looking at the chemical structure of these compounds, a lot of these are phenolic compounds, meaning they, they have one or two, usually two benzene rings attached together and they s-... They look very similar to one another. There's been a lot of basic science, animal study, and retrospective human studies in the last two or three years that suggest that some of these chemical compounds, particularly oxybenzone, particularly octocrylene, particularly, um, octinoxate, um, that can have endocrine disruption or affect the nervous system because they mimic a lot of biologic phenolic compounds and a lot of biologic hormones. If you actually look at the structure of oxybenzone, it looks very similar to the structure of bisphenol A, which has been now banned in a lot of the lining of plastic bottles. Why? Because the same concept. Now, the data is not...... 100% one way or another, but there's enough smoldering evidence that makes me think, "Hmm, we should reinvestigate this." And in fact, the FDA's proposed final order in 2021 changed these chemicals from GRASE, Generally Recognized As Safe and Effective, to not-GRASE because of these concerns. There's data that suggests that the chemicals are found in breast milk, amniotic fluid, blood plasma, urine. So there's a lot of things that we don't know and I always say this, in science, we take two steps forward and then maybe one step dia- diagonally or sideways 'cause we ran into unexpected things. I tend to recommend mineral sunscreens because they don't have any of that data, they haven't for the last 30, 40 years, they're considered safe, and in fact, for young kids, particularly those six months and under, the American Academy of Dermatology and the American Academy of Pediatrics generally recommends avoiding chemical sunscreens. Why? Children's skin, particularly infants and toddlers, behaves more like mucus membranes than adult skin. Their barrier is not as tightly woven, so they absorb these things at a much higher concentration. So if you are to apply something on kids, especially young kids six months or under, we recommend minerals to begin with. So I say if you have a pool of compounds that has maybe even smoldering evidence on the basic science level that something's off versus a, a group of, uh, compounds that have really no data, which one would you pick? And they do the same thing.

Andrew Huberman 1:20:00 Mm-hmm.

Dr. Teo Soleymani 1:20:01 I'd naturally gravitate towards that.

Andrew Huberman 1:20:03 So the takeaway for me is physical barrier, no issues. Mineral-based sunscreen, safest. So that's zinc oxide, titanium dioxide.

Dr. Teo Soleymani 1:20:17 A- and that's mineral not like powder, not mineral powder, but mineral topicals because mineral powders

Dr. Teo Soleymani 1:20:24 are a whole nother issue we'll talk about but...

Andrew Huberman 1:20:26 Okay. And then chemical-based sunscreens, um, probably best avoided. Um, and then you mentioned polypodium.

Dr. Teo Soleymani 1:20:36 Yeah.

Andrew Huberman 1:20:36 So this is a pill, it's a supplement basically that one can take. I only call it a supplement because-

Dr. Teo Soleymani 1:20:41 Yeah.

Andrew Huberman 1:20:41 ... um, it's not a prescription drug, correct?

Dr. Teo Soleymani 1:20:44 Yeah.

Andrew Huberman 1:20:44 Um, that protects your skin from UV damage from the inside.

Dr. Teo Soleymani 1:20:49 Yeah. So exactly right. Mineral-based creams and lotions, I tend to prefer and recommend in my practice, and most people will, if you're worried about any risk, any consequence. Chemicals, I tend to personally avoid. Now this may not be in line with all my dermatology colleagues, but I tend to avoid them and I re- do not recommend them for kids. In terms of things that you can do in addition to provide sun protection, polypodium's a fern from the Amazon rainforest that was discovered when they studied an indigenous population that would eat this fern before they would go on their fishing expeditions on the Amazon, and they'd be gone for three days, they'd eat this fern and come back not burned. So a lot of studies were done on this fern in the last five, 10 years that showed it increases your skin's minimal erythema dose, the amount of redness your skin gets from UV exposure, that's our general barometer for effectiveness, without any topicals. It's taken or ingested orally. I personally use a form called sun powder that also has nicotinamide in it, and we can talk about nicotinamide later, but if... In and of itself it works great. In conjunction with topicals, you get the best of both worlds, you get internal shielding and external shielding. Now it is a supplement, so it's not a controlled drug the way the FDA regulates sunscreen, so it isn't really a sunscreen, but it's a way to prevent sunburns, increase the amount of time you can be outside, and increase the efficacy of your topicals. So if you're somebody who has very fair skin who burns all the time or if you're somebody who has, like, what we call sun hives or, or p- bl- um, prickly sun rash, PMLE, um, this is an added thing that you can use that will boost your sun protective factors. It's awesome. And if you're somebody who's active, like, you're in the water or you're, you know, exercising or you're playing a sport and you can't reapply, I, I love polypodium for that added benefit.

Andrew Huberman 1:22:50 What are the dosages of polypodium that are useful and are there any side effects?

Dr. Teo Soleymani 1:22:54 Yeah, great question. So there's been a wide variety of doses, um, investigated anywhere from 50, 100, 240, 480. Generally, some-

Andrew Huberman 1:23:05 You said 1,500 to f-

Dr. Teo Soleymani 1:23:07 No, uh, sorry 50 milligrams-

Andrew Huberman 1:23:08 50 milli-

Dr. Teo Soleymani 1:23:08 ... 100 milligrams-

Andrew Huberman 1:23:10 Okay.

Dr. Teo Soleymani 1:23:10 ... 240, 480.

Andrew Huberman 1:23:11 Uh-huh.

Dr. Teo Soleymani 1:23:12 Um, somewhere in the between 50 and 480 milligrams is what's commonly used. The most common side effect can be a little, um, upset stomach if you can't tolerate the plant, for whatever reason.

Andrew Huberman 1:23:26 It's taken daily?

Dr. Teo Soleymani 1:23:27 It's taken... You can either take it daily as a method of preventing premature photoaging and pigmentary change or you can take it as an as-needed, an hour before you get sun, um, to shield you from the sun. Um, the other thing that it helps prevent, um, that some sunscreens cannot, particularly the chemical sunscreens cannot, is the effects of visible light. So there are certain skin conditions, the most common is melasma, which a lot of women have. You know, it's I think the bane of their existence, it used to be called the mask of pregnancy. And melasma is something that is very sensitive to both UV and visible light. Chemical sunscreens don't do a good job blocking visible light. Polypodium's been shown to help block the effects of visible light as well which makes melasma worse. It's this discoloration that we see mostly in women usually after pregnancy or women who are on birth control. It is really challenging to treat and sun protection is the first line, like-... diligent sun protection, but we found that supplementing with polypodium enhances this and makes patients' treatments more effective.

Andrew Huberman 1:24:38 Interesting, and you mentioned Sun Powder as a potential-

Dr. Teo Soleymani 1:24:42 Yeah.

Andrew Huberman 1:24:42 That's a brand name?

Dr. Teo Soleymani 1:24:43 So yes, Sun Powder is a brand. It's, um, a product that I helped formulate with one of my colleagues, um, over at Harvard who's an, a laser and aesthetic dermatologist, Harvard-trained, and this is something that we came up with when I was up at Stanford and it's a, it's a supplement dedicated to skin health and it does two things. I take it daily myself as a single scoop. It helps reduce your skin cancer risk, your non-melanoma skin cancer risk by up to 30%, and the data was published in the New England Journal of Medicine in a phase three randomized trial for one of the ingredients. The other ingredient, obviously, is ni- is polypodium, and I take that, one, to prevent, you know, sun-related changes, but also help reduce my risk of burning. Often when I personally find the need for sunscreen, it's when I can't apply. Always at the water, I'm swimming, you know, my, my son, he's seven, he races on a swim team. I cannot get this kid to reapply sunscreen, so this is a supplement that I, I give him and we... It took us several years of formulation and testing, including MED testing, which is minimal erythema dose testing to come up with. It's easy over-the-counter and it's one of many supplements that contain polypodium. I just like it 'cause it's a single scoop and I mix it into my morning drink and I'm done.

Andrew Huberman 1:26:01 Terrific.

Andrew Huberman 1:26:03 I think we both agree that the mineral-based sunscreens are going to be the best option of the ones out there if one is at all concerned about some of these chemical components and chemical sunscreens.

Dr. Teo Soleymani 1:26:14 Absolutely.

Andrew Huberman 1:26:14 Is that fair, fair enough?

Dr. Teo Soleymani 1:26:15 Abs- Absolutely agree.

Andrew Huberman 1:26:15 Yeah, so, uh, within that category, are there particular things to look for? Um, I'm not necessarily trying to aim for particular brands here-

Dr. Teo Soleymani 1:26:24 Yeah. Yeah, yeah.

Andrew Huberman 1:26:25 ... but given that I have no relationship to any skincare products, um, I would just like to know which ones-

Dr. Teo Soleymani 1:26:31 Yeah.

Andrew Huberman 1:26:32 ... to, to look for, or will any zinc oxide and/or titanium dioxide-containing sunscreen, provided there are no chemical components in there-

Dr. Teo Soleymani 1:26:41 Yeah.

Andrew Huberman 1:26:41 ... besides the inactive ingredients, of course-

Dr. Teo Soleymani 1:26:44 Yeah.

Andrew Huberman 1:26:44 ... um, will any suffice? Because i- in that case, people can just shop for cost or availability.

Dr. Teo Soleymani 1:26:48 Yeah. So, I tend to take a pragmatic approach in this. My, my recommendation is a brand that you will use, because if I recommend a brand and you don't like it, it doesn't feel good or smell good, you're never gonna use it and it's a waste of your money and time. So number one, any brand that is mineral-based is fine. Y- what you're looking for is broad spectrum coverage, which m- almost all mineral-based sunscreens provide. Broad spectrum meaning UVA and UVB, and we know these two UV forms do different things in the