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

Huberman opens with a framing question rather than a recommendation: if the skin replaces itself, what fraction of the skin he is wearing at 49 will still be there a year from now? Soleymani's answer sets the terms for the rest of the conversation. The surface turns over roughly monthly, but the stem cells in the lowest portion of the epidermis persist and keep generating new skin cells, so the organ is continuously rebuilt from a resident pool rather than replaced wholesale. He draws an explicit parallel to the gut lining, which he says also renews on a 28-day cycle.

You have new skin, brand new skin every 28 days.

The clinical consequence Soleymani emphasizes is regenerative capacity. Skin is one of the few organs that can regrow after injury, which is why it functions as a test bed: you can grow new skin, and you can use it as a model platform for studying diseases of other kinds. That claim is the load-bearing premise for everything that follows, because a tissue that rebuilds itself monthly is a tissue whose appearance can, in principle, be altered by what you do to it. Huberman makes that inference explicitly later, asking whether people who became less stressed would see skin health and appearance improve, and Soleymani answers in the affirmative.

Before answering, Soleymani insists on anatomy, and the anatomy explains why he splits stress into two mechanisms. Skin is three layers, epidermis, dermis, and subcutaneous fat, and the dermis is where most of the biologic activity sits: blood vessels, the nerves serving sensation and movement, hair follicles, oil glands, and sweat glands. Because the vasculature and the innervation are both resident there, a systemic stress signal has a direct physical substrate to act on. Acute stress, he says, produces release of chemical messengers in an autocrine, paracrine, and holocrine fashion, meaning signaling that acts on the secreting cell itself, on neighbors, and through shed cellular contents.

His concrete example of acute stress is hair shedding, and he offers three settings from ordinary clinical life: students during finals, patients after a major medical illness, and patients after pregnancy. Hair is treated here as a readout rather than a separate topic.

It's a biosensor of our well-being, and we see this all the time.

Chronic stress is assigned a different mechanism and a different molecule. Cortisol, which he places in the same chemical family as prednisone, cholesterol, testosterone, and estrogen, does something distinct from its relatives: it breaks tissue down so the body can use the breakdown products under duress. He connects the vascular arm of this to visible pallor. In the immediate phase, fight-or-flight constricts cutaneous vessels to shunt blood to muscle, which is why a stressed person can look pale or gaunt; over time, the dermis and fat deteriorate. The two effects are therefore not the same process running longer, but a fast vasoconstrictive response and a slow catabolic one.

The evidential weakness is stated by Soleymani himself and is worth flagging, because it is easy to lose in the confident delivery. He calls stress "something that is impossible to quantify in a lab measure, but very easily seen on exam," and explains the post-vacation glow as something you cannot put in a test tube. In the same breath he asserts "actual quantifiable improvements in skin health" when people move away from a stressor. Those two statements pull in opposite directions, and the episode does not resolve the tension; the case for stress affecting skin rests here on clinical impression and on the inference from known vascular and cortisol physiology, not on a measurement presented in the conversation.

Huberman poses the question with his own habits on the table, yerba mate in the morning and coffee later, and folds in his own uncertainty about whether chronic caffeine causes vasodilation. Soleymani's answer separates potency from dose. Caffeine is a known vasoconstrictor, but at the quantities found in coffee, tea, and equivalent beverages, the amount reaching the small capillaries and arterioles of the skin is minute and transient, and a compensatory vasodilation usually follows. His verdict is that the cutaneous effect is less dramatic than commonly portrayed.

Two qualifications keep this from being a clean clearance. First, he reports that people with chronically high caffeine intake tend to produce more sebum, and says the reason is unclear, possibly the vasoconstriction itself, possibly a compensatory mechanism not understood. Second, he states plainly that the data on whether caffeine is deleterious, beneficial, or net neutral for skin is equivocal. His own experience of not noticing vasoconstriction is offered as experience, not evidence, and he notes that patients with rosacea are far more sensitive to vascular changes and may see color shifts that others do not.

The most useful correction in this section is a substitution of variables. The old dermatological advice to rosacea patients to avoid coffee and tea was aimed at the wrong target, because the caffeine concentration reaching skin is minuscule. The actual trigger, he argues, is the heat of the drink.

It's actually the temperature of the beverages we drink.

Nicotine gets the opposite treatment, and the distinction is route and concentration rather than pharmacology alone. Smoked nicotine delivers a higher local concentration to skin through inhalational and direct effects, producing measurable vasoconstriction; Soleymani ties this to faster aging in smokers and to worse wound outcomes and healing in surgical patients who smoke. The argument for why this accumulates is behavioral: people who use nicotine rarely do so once a week, they use it daily or several times a day, so a transient effect becomes a chronic one. His recommendation is unambiguous, to refrain from nicotine if you want healthy, younger-looking skin.

Vaping is placed alongside smoking rather than exonerated, with an honest admission about mechanism: matched for nicotine content, the same vasoconstriction appears, but whether the driver is the inhalation or the local nicotine concentration is unknown. Gum and patches are treated as genuinely lower risk, on pharmacokinetic grounds. Because oral nicotine must pass through the digestive tract and then the bloodstream, and a patch must also go through the bloodstream before reaching skin, the concentration arriving at the skin is much lower. The practical illustration is surgical: patients who smoke or vape are transitioned to gum or patches before operations to blunt withdrawal without the cutaneous constriction.

Huberman brings in a prior episode's conclusion, that zero alcohol is healthier than any and that up to two drinks per week is probably acceptable for a healthy adult without alcohol use disorder, then asks for a breakdown into acute direct effects versus chronic effects routed through sleep and the microbiome. His phrasing makes the mechanism he suspects explicit: alcohol disrupts the gut microbiome, which then disrupts skin.

Soleymani's answer is structurally simple even though he calls the connection complicated and convoluted. The acute effect is osmotic: alcohol is a mild diuretic, so the body sheds water, which is why you wake up thirsty and parched, and why the face shows hollowing in areas that normally have volume and suppleness, producing the under-eye bags and the hangover look. The skin then compensates by producing more sebum against the drying. The chronic version of the same loop is congested skin, blackheads, and whiteheads as the skin keeps overproducing oil to stay supple.

He then describes a genuinely different pathway that is genetic rather than dose-dependent. In people who cannot efficiently break down acetaldehyde, he specifically names Southeast Asian populations, the toxin accumulates and drives vasodilation, producing the immediate bright red flush. He notes the common term for it, the flush or glow or incorrectly called the Asian glow, and attributes it to acetaldehyde buildup in the skin rather than to alcohol itself.

The chronic case is where the reasoning becomes most confounded, and Soleymani concedes as much. Long-term alcohol use is associated with lifestyle choices that independently worsen skin, and gut effects depend on consumption patterns, dose, and concentration. Higher-percentage alcohol produces greater problems on every axis he lists, diuresis, microbiome, and habits, while lower-concentration drinks in some settings may be net neutral or possibly positive, a possibility he explicitly declines to settle.

Huberman closes the loop by noting he has heard no positive cutaneous effect of alcohol, and Soleymani agrees that the skin mirrors what is seen in brain and liver: net neutral at best, net negative most of the time. The concession about confounding is what makes this claim credible rather than overreaching.

Huberman extracts a principle from the preceding material, that improved blood flow and hydration status both matter, and asks whether patients should be told to drink a set volume of fluid for skin. Soleymani uses the question to dismantle a common belief. Every study that has looked at transepidermal water loss, he says, has failed to show a strong connection between regular fluid intake and skin hydration status. What he posits instead is genetic encoding: some people simply have drier skin and need topical methods to moisturize, others have oilier skin where sebum does the work. The exception he grants is real dehydration, in athletes or the actively sweating, which is a systemic fluid problem and a different story.

This reframing matters because it relocates the intervention from drinking to barrier protection, which is why he says most dermatologists recommend a moisturizer and why he personalizes it: his own skin is oilier and needs less, while drier skin needs barrier protection to minimize water loss. The choice of product then follows from skin type rather than from price or precedent.

His selection criteria are concrete. Non-comedogenic is the first term to look for, meaning tested not to clog pores, so that solving one problem does not create another. The second is vehicle, and he lays out three: ointments, which are greasy petrolatum-based products and the most effective at moisturizing; creams, which are water emulsions with oil suspended in them; and lotions, which he describes as powders resuspended in water. Dermatologists, he admits, favor greasier formulations because they give the best barrier protection, but the right answer is skin-type dependent, with eczema-prone patients needing occlusion and acne-prone patients breaking out from it.

The packaging heuristic he offers is jar versus pump. Jars tend to be more occlusive and more moisturizing but can drive acne and breakouts; pump bottles tend to be lighter, partly, he says, because powders in suspension require alcohol in the product to flow through the mechanism. That last claim is asserted rather than sourced, and it is the kind of formulation detail a listener should treat as clinical rule of thumb rather than established fact. The exchange that follows is a clean test of the framework: Huberman names Aquaphor, Soleymani calls it greasy and great, and confirms it is appropriate for eczema and wrong for acne, because the more occlusion a product provides the more it clogs.