By John Koten

After around age 20, human skin slowly has a harder time looking after itself. But there's help out there -- too much of it in fact.

There aren't quite a zillion creams, serums and other potions promising to take care of your aging face, although it often seems like there are. To evaluate which of these elixirs work best, it pays to know something about the key ingredients to look for.

As a 70-year-old man on a quest to improve my aging face, my go-to expert was Dr. Adam Friedman, the chair of the dermatology department at George Washington University. Friedman is a consultant, a researcher in the field and holder of a "Beauty Genius" award from Elle magazine.

Here are edited experts of a conversation with Friedman.

Stay hydrated

WSJ: Let's focus on what's in the jars -- the ingredients that really matter for skin health. Where should we start?

ADAM FRIEDMAN: With hydration. It is critical to healthy skin. Achieving it requires not just dumping on moisture, but supporting the biologic processes that create and maintain the stratum corneum, the outer layer of skin that's also commonly referred to as "the moisture barrier." Enzymes play a critical role in keeping this barrier intact. But they cannot function without water. And that's just one of many reasons why dehydrated skin is dysfunctional skin.

WSJ: Humectants can play an important role helping to trap and retain moisture. Which ones work best?

FRIEDMAN: Glycerin, hyaluronic acid, sodium PCA and urea. Urea deserves special attention -- it's not just a humectant, but activates channels that facilitate water and glycerol transport across cell membranes. Studies show urea-based topicals can increase epidermal thickness and gene expression of key proteins in the top layer of skin.

WSJ: Apparently, smearing fats on my face is also a good thing for skin health.

FRIEDMAN: Correct. To reinforce the "mortar" that holds cells together, we deploy ceramides (especially Ceramide NP and EOP), cholesterol, squalane and linoleic acid. Some ingredients like oat oil can also stimulate ceramide production -- turning on the faucet instead of just refilling the pool, which I actually prefer.

WSJ: There's an increasingly popular activity called "slugging." This messy act involves applying gloppy Vaseline as the final step in a routine. It's certainly understandable why no one seems to be doing this during the day, but is it a sound practice?

FRIEDMAN: Ingredients like petrolatum [petroleum jelly] or other oils physically block water loss. Petrolatum, in particular, has been shown to reduce water loss by up to 98% and even accelerate barrier recovery by stimulating the skin's ability to make its own lipids. I prefer partial occlusives like silicone derivatives. They don't fully obstruct water loss but have a better feel and are much less likely to block pores.

WSJ: How about vitamins A, B, C and E?

FRIEDMAN: Each of these plays a unique and synergistic role. Vitamin A (retinoids) is a dermatologist's multitool and the gold standard for photodamage and acne. It boosts collagen production and cell turnover. Prescription retinoids (like tretinoin or trifarotene) are backed by decades of data. Over-the-counter forms like retinaldehyde or retinol can be gentler and still effective.

Age spots

WSJ: I've become a big vitamin B3 fan because it made my age spots go away.

FRIEDMAN: Yes, niacinamide is very versatile. It strengthens barrier function, reduces hyperpigmentation, regulates oil and even has anti-inflammatory effects.

WSJ: Next up is one that should be applied every morning followed by sunscreen: vitamin C.

FRIEDMAN: Ascorbic acid is a potent antioxidant and helper molecule in collagen production. But here's the catch -- ascorbic acid is unstable in water and light. Stabilized forms like tetrahexyldecyl ascorbate offer better skin penetration and shelf life. Pairing C with E and ferulic acid improves efficacy.

WSJ: Why not just dump all these ingredients into one cream?

FRIEDMAN: It's not that simple. The delivery system is as important as the drug itself. These ingredients have different solubility profiles (oil vs. water), pH requirements and stability characteristics. A highly acidic vehicle needed for ascorbic acid, for instance, would destabilize peptides or degrade certain lipids. The formulation vehicle -- not just the active ingredients -- is the science. This is why I generally recommend products from large brands that have the resources and expertise to do it right.

WSJ: So, drat, there's no chance of avoiding a multistage routine. OK, let's turn to growth factors, which sound like something I could use to be 6-foot-2.

FRIEDMAN: Growth factors [GFs] are naturally occurring proteins that signal cells to grow, divide and repair. In skin care, they aim to mimic these natural regenerative processes. Delivery matters: Topically applied GFs may not penetrate the skin unless encapsulated or paired with technologies like liposomes.

Peptides and CBD

WSJ: Peptides are being heavily featured in the marketing maelstrom out there. But there seem to be hundreds of different kinds with new ones being produced every day.

FRIEDMAN: Peptides are short chains of amino acids that act like text messages to your skin cells -- triggering collagen synthesis, reducing inflammation or modulating pigment.

WSJ: Some of the claims seem exaggerated to me.

FRIEDMAN: The peptide must be stable, delivered in sufficient concentration and survive skin penetration. Many brands throw peptides into creams at trace levels and tout unproven claims. I'm skeptical of any peptide that doesn't come with published evidence or explain its delivery system.

WSJ: CBD (cannabidiol) has faded as a skin-care ingredient. Is it worth a second look?

FRIEDMAN: Absolutely! My lab has published on nanoencapsulated CBD for reducing inflammation and photodamage, especially UVA-induced DNA damage. CBD has antioxidant, anti-inflammatory, sebostatic and antimicrobial properties. CBD is not a cure-all, but it can be a valuable tool in the dermatologist's kit. [Friedman is the co-inventor of a technology used to encapsulate CBD and other skin-care ingredients.]

WSJ: Let's end with epigenetics -- is it hype or hope?

FRIEDMAN: Epigenetics explores how environmental factors influence gene expression without altering DNA itself. Skin aging isn't just genetic -- it's epigenetic. UV radiation, pollution and stress all impact gene expression related to collagen breakdown, inflammation and pigmentation. These are still early days, but brands are developing topicals that can "switch on" youthful gene expression patterns. It's a thrilling frontier -- but right now, I'd still call it early science.

John Koten is a writer in New York. He can be reached at reports@wsj.com.

(END) Dow Jones Newswires

May 21, 2025 11:00 ET (15:00 GMT)

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