A Chemists’ Guide to Skincare That Works

Stem cells and snail slime are not on the list

Credit: Makidotvn/iStock/Getty Images Plus

TThe amount of skin care options available to slather on your face is dizzying. There are lotions, serums, masks, oils, and acids as well as stem cells, snail slime, charcoal, and even diamonds. And with complicated ingredient lists, it can feel like you need a chemistry degree to purchase a basic moisturizer.

Navigating the $134.8 billion global skin care industry is made even more confusing because many dermatologists have skin in the game. They might be paid consultants for cosmetic companies, sell high-end nonprescription products at their private practices, or even have their own skin care lines they want to promote.

“If these products work so well, number one: You wouldn’t see dermatologists aging, and you do,” says New York-based dermatologist Dr. Fayne Frey, author of FryFace, a website aimed at demystifying skin care. “Number two: You wouldn’t see all my cosmetic dermatology friends offering laser treatments and peels,” she continues, because if the products worked well, doctors wouldn’t have to rely on more complex treatments.

So what do impartial cosmetic chemists and dermatologists like Frey recommend? And what’s overpriced junk that will just fill up your pores while emptying your wallet? Read on.

Retinoids

The three basic tenets of skin care remain the same: Wash your face, use sunscreen during the day, and apply a moisturizer at night. But if you’re looking to go beyond the basics, it helps to have a little insider knowledge about the industry. Every skin care product you can buy online or at a drugstore is technically a cosmetic, meaning it could potentially change the appearance of your skin, but it cannot, by definition, change the skin cells themselves. Only drugs approved by the Food and Drug Administration (FDA) are allowed to alter the structure or function of your skin.

“Anything that’s regulated as a drug is going to have the most evidence behind it,” says Michelle Wong, a PhD chemist and science educator who moonlights as the beauty blogger Lab Muffin. (Wong is not affiliated with any brands, although she does occasionally receive free product samples and writes sponsored posts. She takes special precautions to alert her readers when that’s the case.)

You can only get a skin care drug with a prescription, just like any other drug. But some of the ingredients in cosmetics are related to ingredients in drugs, which suggests they may have better efficacy.

“Anything that’s regulated as a drug is going to have the most evidence behind it.”

The only FDA-approved drug to treat signs of aging and sun damage, such as fine lines, dullness, and pigmentation, is Renova, the brand name for a product containing tretinoin. Tretinoin is a type of retinoid, which is a derivative of vitamin A. Two additional types of retinoids are FDA-approved to treat acne and psoriasis. Other slightly milder forms, most notably retinol, are common in over-the-counter skin creams.

Every expert interviewed for this article said that if you use anything on your skin beyond the basic sunscreen and moisturizer, retinoids — either drugstore or prescription — are your best bet.

“At bedtime, you want to repair the damage that has been done to the skin,” says Dr. Diane Berson, an associate professor of dermatology at Weill Cornell Medical College. “Besides using a hydrating product, there are some ingredients that can repair some of the damage inflicted on the skin, specifically from ultraviolet light, radiation, and pollution. The ingredients that we usually recommend are retinoids.” (Berson has served on the advisory board or as a consultant for cosmetic and pharmaceutical companies, including Sienna Biopharmaceuticals, La Roche-Posay Laboratoire Pharmaceutique, Medicis Pharmaceutical, and Procter & Gamble.)

Retinoids work by increasing skin turnover — when old dead cells on the surface of the skin are shed and replaced. This cell renewal process can help fade dark spots and keep pores unclogged, which is how the products work to treat acne.

Prescription retinoids, and potentially retinol as well, also increase collagen production in the underlying layer of the skin, called the dermis. Collagen keeps skin looking plump and firm, and production of it decreases with sun exposure and age. Applying collagen itself directly to the skin doesn’t help, however, and the verdict is still out about whether it’s effective when taken as an oral supplement. Topical retinoids do seem to stimulate collagen production in the dermal cells themselves. One study found that Renova increased collagen production by 80% over the course of a year.

Even with a prescription, the benefits aren’t guaranteed. Just 10% of people in a clinical trial for Renova saw a moderate improvement in the appearance of fine lines. Most people, 75%, saw no change or only minimal signs of improvement. Prescription retinoids also frequently come with side effects such as burning, stinging, and irritation.

“I have never in 30 years seen anyone come to me looking 20 years younger from using Renova,” says Frey. “So do the benefits outweigh the [side effects]? I don’t think so. But there is a huge pool of dermatologists, my colleagues, who disagree with me.”

Niacinamide

Although they can’t technically change the structure or function of skin, some cosmetic skin care ingredients may have an effect on its appearance, according to some research.

One popular ingredient is niacinamide, a form of vitamin B3. Like retinoids, niacinamide appears to increase cell turnover on the top layer of the skin and can reduce dark spots. It also helps the skin maintain its normal barrier function by increasing levels of ceramides — natural fats the skin produces to keep environmental chemicals out and skin chemicals in, most notably water. Most moisturizers work this way, by adding fats and other protective ingredients to the skin to help maintain water levels. But niacinamide appears to have a benefit beyond traditional moisturizing ingredients.

Niacinamide is also an antioxidant, which means it can bind to and disarm harmful free radicals, which damage skin and contribute to the appearance of aging. The skin produces its own natural antioxidants, but UV exposure can deplete those, too. Theoretically, replacing the antioxidants may reverse or slow signs of sun damage and aging.

“Routinely, I do recommend using a topical antioxidant in the morning along with sun protection with SPF because while sunscreen does block out a large percentage of the sun’s ultraviolet rays, it doesn’t block out them all,” Berson says. “The way ultraviolet light damages the skin is by creating free radicals, what we call oxidative damage. Using antioxidants counteracts that. It’s a second level of protection along with the sunscreen.”

Vitamin C

Vitamin C, or ascorbic acid, is another popular antioxidant that experts say may have both protective and regenerative properties. Studies, albeit ones with small sample sizes, have shown that vitamin C can increase collagen production in addition to its antioxidant effects.

A major caveat, however, is that the ingredient might never actually make it to your face. Vitamin C is highly unstable, meaning it breaks down when exposed to water, air, and UV light. Perry Romanowski, a former industry cosmetic chemist who now runs several skin care blogs, says it’s virtually impossible for vitamin C to go through a production process without being exposed to one of those three elements.

“You have to imagine how these things are made,” he says. “They have these big steel tanks where they’ll make the batch. When [vitamin C] gets dumped into the batch, it starts to react then. And by the time the batch is done and it’s put into bottles, it’s already degraded a certain amount. Then it sits on the shelves until it gets bought by a consumer. It just steadily degrades to the point where the products are not going to be more effective than just the moisturizer that you’re buying [it in].”

Manufacturers have tried to produce more stable forms of the vitamin, which is why you often see ascorbic acid sold under a variety of different names. Whether these alternatives have the same benefits as the vitamin itself is largely unknown.

DDespite their purported effects, niacinamide and vitamin C are cosmetic ingredients, not drugs. That’s why the claims for these types of products are vague: “Smooth,” “rejuvenate,” “glow,” “plump” — none of these are medical terms.

“Cosmetic products are only legally allowed to affect the appearance of skin,” says Romanowski. “When you see claims like… reducing wrinkles, a cosmetic can’t really do that. The only thing a cosmetic can do is to make it look like you have less wrinkles.”

Frey points out that the manufacturers are well aware of this. “If [their products] were really intended to change the skin they would be drugs, and they would go through the FDA, and they wouldn’t be over-the-counter,” she says.

So, how do you decide what to buy?

“If you took the products on a blinded basis, you would not be able to sort them from effectiveness based on how much they are charged.”

First, get a sunscreen you like enough to use every single day. Experts agree this is the single best product to spend your money on. Study after study shows sunscreen is the best protection your skin can get, and shielding your skin from UV rays may actually help it rejuvenate itself.

Increasing moisture levels with a good lotion or cream can change how skin looks, too. Virtually all moisturizers work in the same fashion; they don’t add water to the skin, but they do help the organ retain its own moisture. The key ingredients are humectants and occlusives.

Humectants, like glycerin or hyaluronic acid, pull water to the top layers of the skin. Occlusives — typically a fat like ceramide or petrolatum — strengthen the skin’s barrier to prevent water from evaporating. These are the moisturizing parts of the moisturizer. The other 90-95% of the product is water, an emulsifier that holds the fat and water together, a thickener to get the mix to a consistency consumers like, and a preservative to keep the product from developing mold or bacteria.

“How well an anti-aging cream or anti-wrinkle cream works, in my opinion, depends on its ability to allow the skin to increase water content,” Frey says. “The industry wants you to buy a night cream and an eye cream and a toning cream and a firming cream and an anti-aging cream and a primer. [But] they’re all formulated very similarly — they’re all moisturizing cosmetics.”

Cost is another factor that doesn’t reflect quality. “If you took the products on a blinded basis, you would not be able to sort them from effectiveness based on how much they are charged,” says Romanowski.

Another possible decision point: choosing natural versus chemical ingredients. Many people take issue with the environmental impact of having palm oil or petroleum in products. Others are concerned about the use of ingredients like parabens, which are a type of preservative, or phthalates, which may be endocrine disruptors.

The bottom line is people should buy things that make them feel good. It really comes down to how much you like the product — the feel, the smell, and the brand. If you want to think of yourself as a La Roche-Posay, Drunk Elephant, or Vintner’s Daughter person, go for it. But know that there may be little improvement functionally between high-end and drugstore products. The biggest difference comes down to marketing.

Health and science writer • PhD in 🧠 • Words in Scientific American, STAT, The Atlantic, The Guardian • Award-winning Covid-19 coverage for Elemental

Sign up for Inside Your Head 🧠

By Elemental

A weekly newsletter exploring why your brain makes you think, feel, and act the way you do, by Elemental senior writer Dana Smith. Take a look.

By signing up, you will create a Medium account if you don’t already have one. Review our Privacy Policy for more information about our privacy practices.

Check your inbox
Medium sent you an email at to complete your subscription.

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store