When it comes to skin care ingredients, few are as well-renowned—not to mention as effective—as hydroxy acids. The category is comprised of two sub-categories—alpha hydroxy acids and beta hydroxy acids, both of which can do a world of good for complexions across the spectrum. But are they right for you? Here’s what to know before you dive in.
Acids can help your entire skin care routine work harder.
According to Dr. Michele Green, a board-certified cosmetic dermatologist in New York, hydroxy acids are chemical exfoliants that work to slough away dead skin cells, revealing smoother, brighter, more even skin underneath. Compared to other types of exfoliation, such as physical scrubs, hydroxy acids are highly efficient. “When used correctly, acids can provide a more controlled exfoliation of the skin, as they can remove several layers of dead skin in just one treatment, allowing skin care products to effectively penetrate the skin,” Dr. Green explains. In that way, hydroxy acids are the key to making the most of all the other products you layer onto your skin.
Alpha and beta hydroxy acids work differently.
All hydroxy acids can help address signs of aging, including fine lines, wrinkles and irregularities in texture and tone, according to Dr. Corey Hartman, a board-certified dermatologist and founder of Skin Wellness Dermatology in Birmingham, Alabama. But which one will work best for you depends on your skin type. Folks with oily skin fare best with beta hydroxy acid (AKA salicylic acid) thanks to its ability to penetrate and clear oil buildup inside pores to prevent future breakouts from forming. Dry, sensitive and combination skin types can experience great results with alpha hydroxy acids like glycolic, lactic or mandelic acid. Some products combine both types of hydroxy acids for the best of both worlds: Try Dr Dennis Gross Skincare Alpha Beta Extra Strength Daily Peel, which blends lactic and mandelic acids (both AHAs) and salicylic acid (a BHA) to help smooth fine lines and clear pores. (Learn more about the different types of hydroxy acids here.)
When it comes to hydroxy acids, more isn’t always better.
Before slathering your skin in acids every day right off the bat, know that, like retinol, it’s best to use hydroxy acids sparingly—at least at first.
“Like retinoids, the constant turnover of skin [that occurs as a result of hydroxy-acid use] leads to a thinner, more delicate topmost skin layer, making it prone to photo-sensitivity,” explains Dr. Adeline Kikam, a board-certified dermatologist in Texas and founder of @brownskinderm. As such, she recommends starting with a patch test to watch for any irritation before gradually introducing acids into your routine two times a week, and seeing how your skin responds before increasing to every-other-day use.
Additionally, when picking out an acid, know that a higher percentage doesn't always lead to better results. “It’s best to start with concentrations under 10 percent,” Dr. Kikam says. “The main BHA is salicylic acid and is usually one to two percent. AHAs such as glycolic acid typically start at about eight to 10 percent.” Once you’ve mastered the lower concentrations, you can kick it up a notch with a more intensive weekly treatment, like Paula’s Choice SKIN PERFECTING 25% AHA + 2% BHA Exfoliant Peel.
The acids in your skin care products aren’t the same as the ones the pros use.
Even if a store-bought product is marketed as an at-home peel, it’s not as strong as the redness- and downtime-inducing professional-strength peels sometimes used by dermatologists and estheticians. Rather, at-home peels are more superficial, in that they’ll benefit texture and tone on a surface level with less intimidating side effects (phew!).
Regardless of whether you go the DIY route, a pro can help you choose the right type of acid to achieve your skin goals. “It is important to ask your provider which acid-containing products are best for your condition and how best to use them appropriately to give you the best results for your skin,” says Dr. Scott Paviol, a board-certified dermatologist in Charlotte, N.C.
All skin tones can use acids—but choose a product carefully.
It’s a common misunderstanding that acids directly trigger melanin overproduction. In reality, Dr. Hartman says that in some cases, overdoing it with acids “can cause increased and exuberant inflammation which then leads to hyperpigmentation and deposition of melanin as a result.”
Because of this, Dr. Paviol says that those with skin of color can benefit the most from gentler acids that are the least likely to cause inflammation. “Mandelic acid, which has the largest molecular structure rendering it the most gentle acid, works beautifully for darker skin types as it yields all the benefits of AHAs without the harsh irritation and poses less risk of causing any post-inflammatory hyperpigmentation,” he explains.
But acids aren’t for everybody.
Namely, pregnant people. While “some acids are safe to use during pregnancy in extremely low strength, such as PHAs and AHAs,” BHAs are off limits while pregnant, Dr. Green says. Your best bet: Before adding an acid to your routine, sit down with your skin care provider for tailored tips pertaining to your specific situation.
