Lactic Acid Is the Gentle Ingredient You Need for Smoother, Younger-Looking Skin

Lactic acid is an alpha hydroxy acid (AHA), a class of chemicals that gently exfoliate the skin, which also includes glycolic, citric, tartaric, mandelic, and malic acids.

But while it’s popping up in more products, lactic acid is not exactly new and has a unique history. “The ingredient was first isolated from sour milk, and it is thought that Cleopatra took advantage of its beneficial properties on the skin by bathing in milk,” says S. Tyler Hollmig, M.D., director of dermatologic surgery at UT Dell Medical School and Ascension Seton in Austin.

Nowadays, lactic acid comes from a variety of sources, including vegan ones, that are typically synthetic and easier to formulate a complete product with. Compared to its ultra-potent cousin, glycolic acid, lactic acid is milder (thanks to its slightly larger molecule size) while delivering similar results, meaning it may be more suitable for those who have easily irritated skin, Dr. Hollmig says. Intrigued? Read on to find out what lactic acid can do for your skin.

What are the skincare benefits of lactic acid?

It’s a top-notch exfoliator.

Lactic acid works by gently exfoliating the outer layer of your skin, explains Dr. Hollmig. Sloughing off the dull, dead cells makes way for the brighter, smoother complexion underneath, research shows.

It may be helpful in reducing acne.

This exfoliation also helps keep pores clear by sloughing away dead skin cells plus excess oil, preventing pesky pimples, blackheads, or whiteheads from forming.

It can help smooth fine lines and wrinkles.

Often, aging skin can especially use some help in the exfoliation department. “Normal, healthy skin cells in the outer layer of the skin shed every two to three weeks. This may slow down due to aging, dehydration, and other environmental stressors, which can appear as rough, scaly, and dull-appearing skin,” Dr. Hollmig says.
In addition to revving up your radiance, lactic acid can boost plumpness. Past research shows that a 5% lactic acid formula applied twice a day improved skin thickness and firmness, says Dr. Hollmig, which translates into smoothing out fine lines and wrinkles. This older, but often-cited study showed that a greater concentration of 12% resulted in even more visible benefits, but he cautions that more potent products may make you more prone to irritation (like redness, itching, or peeling), particularly for sensitive complexions.

It can treat bumpy skin.

Beyond the face, lactic acid is often incorporated into body lotions. Most notably, it’s used to treat keratosis pilaris, a.k.a. “chicken bumps” that appear on the backs of your arms or on the legs. The skin condition is harmless, but is often bothersome. Lactic acid can take care of these little bumps, says Dr. Hollmig, but you have to apply the lotion regularly long-term for best results.

Are there any negative side effects of using lactic acid on your skin?

Lactic acid is known to be gentler and more hydrating compared to other AHAs. For that reason, it may be suitable even if you have sensitive skin, says Dr. Hollmig. That said, if you find that the ingredient makes you red and irritated, consider using a product with a lower percentage of lactic acid or skipping it entirely.
Important note: Since all AHAs can make your skin more sensitive to the sun, always apply sunscreen before you head outdoors, whether you applied lactic acid that morning or the night before.
If you’re pregnant, lactic acid is a safe option, says Dr. Hollmig. Your dermatologist and OB/GYN will likely suggest skipping popular anti-aging ingredients, like retinoids, so lactic acid can be a good substitute during this time.

Prevention