The use of acids in skincare formulations is nothing new, but the skincare-buying public’s keen – and growing – awareness of them is. Perhaps it’s because acid names once relegated to the far corners of ingredients labels are now found front and center, increasing our collective familiarity. Or maybe it’s that we’re all more ingredient-fluent in general. Dr Chaneve Jeanniton, a Brooklyn-based oculofacial plastic surgeon and founder of Epi.logic skincare, credits the increasing interest in acids to the fact that they’re simply an effective means to an end. “If you think about recent trends in skincare, like the glass- and dewy-skin movements, a predilection towards acids that resurface the complexion makes a lot of sense,” she says. But while many of us can namecheck acids, we may not be well-versed in what each one can do for the skin.
“This group of exfoliating ingredients – naturally occurring or synthetic – exfoliate by weakening the cellular glue that holds the cells together,” says Boston-based dermatologist and co-founder of Atolla, Dr Ranella Hirsch. And they can work in two ways, says Jeanniton: “They lift off the build-up of dead cells on the skin’s surface to reveal a brighter, smoother complexion; or they penetrate into pores to break up build-up and help clear breakouts,” she says. For New York-based Danuta Mieloch, esthetician and founder of Rescue Spa, they are tried-and-true skincare wonders: “There’s a lot of flexibility when using acids, and it’s one of the quickest and most effective ways to tackle a multitude of skin concerns, from hyperpigmentation and large pores to skin texture and breakouts,” she adds.
Shorthand for alpha hydroxy acid, this family of acids, including glycolic, lactic and mandelic, are used primarily to address discoloration, skin tone and sun damage. For Jeanniton, glycolic deserves top billing. “It’s the acid against which all other acids are compared, because it’s such a superstar,” she says. “It works on the skin surface by loosening the bonds to shed dead skin cells, revealing fresher, brighter layers underneath.” That glycolic acid has a smaller molecular size also means, Jeanniton adds, that it can penetrate more easily and more effectively into the deeper layers of the dermis to increase collagen production and target fine lines and wrinkles. Lactic acid, derived from lactose, has larger molecules, so while it doesn’t go as deep as glycolic, it has less potential for irritation, making it ideal for sensitive skin, plus it’s hydrating. “Lactic acid increases water retention and ceramides in the skin’s protective barrier,” says Jeanniton. With the largest molecular size, mandelic acid is the gentlest of the AHAs, plus it can increase oil production, making it a good choice for dry skin. And while used on pigmentation, Jeanniton points out that further studies are necessary to clarify evidence of its efficacy on hyperpigmentation in darker skin tones.
The best known of the beta hydroxy acids is salicylic acid, the go-to ingredient for treating acne and breakouts. In the same family as aspirin, salicylic acid shares similar anti-inflammatory properties, as well as an ability to calm and soothe. “It’s oil-soluble and can penetrate and clear inside the pore,” says Jeanniton. “When used regularly, salicylic acid not only helps clear existing acne, but it also prevents new acne and blackheads from forming.”
The newest player in the acid category, PHAs – like gluconolactone, galactose and lactobionic acid – are known as the second generation of hydroxy acids. “These gentle exfoliants work in a manner similar to the AHAs, but they also have antioxidant properties, which means they help protect the skin against free-radical damage,” says Jeanniton, who sees them as an ideal option for anyone with rosacea or atopic dermatitis.
THE BEST APPROACH TO ACID PEELS
When it comes to acids, a slow and steady approach wins the race. “These active ingredients carry a meaningful concern for irritation, so you’ll want to take care when using them alongside other products that can also irritate, such as vitamin-A derivatives,” says Hirsch. The same goes for vitamin C. Her advice is to introduce them into your routine one at a time, and only after your skin is already tolerating whatever you are using. “It’s OK to then combine active products once your skin has acclimatized,” says Mieloch. While many brands boast high acidity levels, more isn’t necessarily better. “Most of the products sold over the counter are fairly safe, but I suggest starting with something mild and leaving the higher percentages to the experts,” says Mieloch.
HOW TO USE ACID PEELS SAFELY
While the majority of skin types can tolerate acids (when used correctly), there is a slight risk of hyperpigmentation if using a formula that’s too strong, so consult a professional or very gently ease into anything new. And don’t go overboard: “A major issue is that people layer multiple exfoliating products when only one is needed to achieve the desired outcome,” says Hirsch. Those with sensitive skin should consider their acid vehicle: “Look for products that get washed off before you experiment with leave-on treatments,” says Jeanniton, while those with an inflammatory skin condition such as rosacea should introduce a gentle PHA only when their skin is under control. Jeanniton cautions against mixing acids with physical scrubs; “The combination is typically too abrasive, and thinning the outer layer of the skin with a scrub will further increase the penetration of your acid and the likelihood of irritation,” she says, and underscores the importance of a daily broad-spectrum UV protection, since skin will be more sun-sensitive.
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