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Ready to feel more confident when reading your beauty products' ingredient labels? Enter, the Allure Ingredient Index. In this comprehensive guide, you'll find everything you need to know about the most in-demand (and under-the-radar) ingredients in your favorite skin-care products.
Everyone's skin is on acid these days — alpha hydroxy and beta hydroxy acids, that is. Within each of these AHA, BHA, and even PHA families lie some of the most popular chemical exfoliants for smooth, glowing skin, like glycolic, salicylic, and lactic acids. We've covered the bases on most of them already, but it's about time we share the basics of lactic acid, in particular, with insight from board-certified dermatologists.
What exactly is lactic acid?
Under the AHA umbrella, you can find lactic acid — one of the gentler options compared to glycolic, which has a smaller, more powerful particle size, New York City-based board-certfiied dermatologist Angela Lamb, M.D., tells Allure.
AHAs, for those who need a refresher, are water-soluble and perform their exfoliating magic on the surface of skin to smooth away dullness, fine lines, and wrinkles. BHAs, on the other hand, are oil-soluble for plunging into the depths of pores to treat and prevent acne and oiliness, as board-certified dermatologist Laurel Naversen Geraghty, M.D., has explained to Allure in the acids episode of The Science of Beauty podcast.
Michelle Lee and Jenny Bailey try a product that proves how powerful acids can be. Then, dermatologist Laurel Naversen Geraghty stops by to help make sense of when and how to use these powerful skin-care ingredients.
Unlike other AHAs, which can be derived from fruit or sugarcane, lactic acid is naturally found in dairy products, "specifically from the fermentation of sugar and starch in sour milk," says Aegean Chan, M.D., a board-certified dermatologist in Santa Barbara, California. However, for skin-care products, it's typically synthetically produced, making it vegan and cruelty-free.
How does lactic acid benefit skin?
Just as all AHAs do, lactic acid breaks down the proteins that bind our skin cells together to increase cell turnover and reduce dullness, Dr. Chan explains. As a result, your skin becomes smoother, more even-toned, and incredibly radiant without dead skin cells laying on the surface of it. In fact, "increasing cell turnover also reduces clogged pores and the chances of developing acne lesions," she adds.
What truly sets lactic acid apart from other AHAs, though, acts as a natural moisturizing factor. In other words, lactic acid mimics a "naturally occurring group of molecules found in our skin that helps to hydrate and maintain the skin barrier," Dr. Chan says.
What skin type is lactic acid best for?
Because it has a larger molecule size than glycolic acid and has less systemic absorption, Dr. Chan and Dr. Lamb recommend lactic acid to their patients of all skin types — even those who are pregnant or nursing.
However, those with sensitive skin should be more careful with it than others. To see how your complexion truly tolerates the ingredient, start off by reaching for it only a few times a week before increasing to daily use, Lamb suggests.
If you are reaching for a product with a lower percentage of lactic acid, around the 5 percent range, it is less likely to make your skin freak out and can definitely be added to your skin-care routine on a daily basis, Dr. Chan notes. Higher percentages (10 to 20 percent) are definitely more effective, but they are more likely to cause irritation.
Also, be sure to avoid lactic acid when your skin is irritated or actively inflamed. "Even though it is gentle, it can worsen skin barrier issues, such as flaring atopic dermatitis or rosacea," Dr. Chan says.
Which ingredients shouldn't be paired with lactic acid?
In this handy guide, we learned retinol-spiked products don't get along well with acids of any kind. Lactic acid is no exception as both accelerate cell turnover, so the combination is too aggressive to be used at the same time. Instead, Dr. Lamb recommends alternating them. "One day, lactic acid; one day, retinol," she adds.
What are the professionals' lactic-acid product picks?
Dr. Lamb enthusiastically shares the Charlotte Tilbury Super Radiance Resurfacing Facial Treatment is her go-to lactic acid product of choice. "Depending on how my skin is feeling, I like to use it one to two times per week," she says. It also counts Allure's senior commerce writer Sarah Han as a fan due to its mild yet effective formula.
In the serum realm, Dr. Chan is all about The Ordinary's Lactic Acid 5% + HA 2%. (Allure editors are too.) When she was pregnant, she slathered moisturizer on top of it every day. She also loves the Biossance Squalane + 10% Lactic Acid Resurfacing Night Serum. "It was very effective, yet gentle, and smelled incredible," she adds.
Allure editors are also devotees to the Then I Met You Birch Milk Refining Toner. Contributing Devon Abelman soaks cotton pads with it and fashions them into her own sheet mask when her pores are acting out. If you're looking for a high percentage of acids, the Ole Henriksen Dewtopia 20% Acid Night Treatment is the way to go for overnight success or splurge on the beloved Sunday Riley Good Genes All-In-One Lactic Acid Treatment.
Read more about acids in skin care:
- How Glycolic Acid Gets Skin Glowing
- Here's Exactly What Salicylic Acid Does to Your Skin
- Why Tranexamic Acid Is the New Secret to Fading Dark Spots
Now, watch Pharell and his dermatologists discuss common skin care concerns:
