Putting “acid” on your face might sound like a recipe for disastrous stinging, burning, and peeling—a la Samantha’s lobster-red face in that unforgettable episode of Sex and the City. Lactic acid for your skin, however, is anything but harsh. It’s one of the least irritating actives around, in fact, and it’s friendly to nearly all skin types.
Along with its gentle nature, it’s also pretty powerful and effective. And the experts we consulted assured us that the standout chemical exfoliant also offers some unique benefits that its counterparts don’t.
To give you a full picture of everything this versatile ingredient has to offer, we asked dermatologists to explain what lactic acid is, what kinds of skin care benefits it can deliver, and some of the best ways to work it into your regular routine—expert-approved product picks included.
What is lactic acid?
“Lactic acid is an alpha-hydroxy acid that comes from the fermentation of lactose, a sugar naturally found in milk,” Margarita Lolis, MD, a board-certified dermatologist at Schweiger Dermatology Group in New Jersey, tells SELF. (Don’t worry, the kind used in skin care products is typically synthetically derived, and not from sour milk.)1
As a quick reminder, the majority of skin care acids fall into one of three categories: alpha-hydroxy acids (AHAs), beta-hydroxy acids (BHAs), and poly-hydroxy acids (PHAs), which differ based on their chemical composition and benefits. As compared to its AHA buddies, lactic acid is one of the least irritating, Dr. Lolis notes.2 This is largely because it doesn’t sink as deeply into the skin.2
For example, glycolic acid, another popular alpha-hydroxy acid, is a smaller molecule that penetrates deeper and faster into the skin, Jeannette Graf, MD, a board-certified dermatologist and assistant clinical professor at Mount Sinai School of Medicine in New York City, tells SELF. And that ups the likelihood of irritation.2
What can lactic acid do for your skin?
As we touched on above, the primary benefit of any alpha-hydroxy acid is exfoliation, although lactic acid is somewhat of an overachiever and goes above and beyond that standard job description:
Lactic acid gently exfoliates.
“Lactic acid works by loosening the ‘glue’ that holds skin cells together, encouraging exfoliation of the dead skin cells and increasing cell turnover,” Dr. Lolis explains.1 And that can lead to a whole host of benefits, including a brighter complexion, reduced hyperpigmentation and dark spots, a smoother texture, and unclogged pores, she says. And the fact that it can do all of that without causing irritation (a common issue with more potent ingredients) makes it ideal for folks with dry or sensitive skin.
However, both of the dermatologists SELF spoke with call out that higher concentrations will be more intense. For example, most over-the-counter, at-home products have a lactic acid concentration of 10% or less, says Dr. Lolis. When the ingredient is used for in-office chemical peels, that percentage is typically higher. Research shows that at 12%, for example, it can penetrate deeper, into the dermis (the middle skin layer), potentially minimizing the appearance of fine lines and wrinkles, she notes.3 (Although, especially if you have sensitive, it’s best to talk to a dermatologist before getting any sort of chemical peel to avoid a skin freakout.)
It’s also hydrating.
Here’s where things get interesting. Typically, exfoliating and moisturizing ingredients are two different things, right? That’s not the case with lactic acid. Along with being an exfoliant, it’s also a humectant, meaning it attracts water, for a hydrating and plumping effect, Dr. Graf points out. (Hyaluronic acid is also a popular humectant, FYI.) That’s another reason why it’s so well-tolerated: Its moisturizing properties help to combat any potential dehydration from the exfoliation, notes Dr. Lolis. This makes it an especially great pick if you’re dealing not only with dullness but also dry skin and flaking.
And it has antimicrobial properties.
According to Dr. Lolis, lactic acid also has antimicrobial properties, meaning it kills pathogens like bacteria.4 That’s important because it can help create a balanced microbiome (the combination of billions of microorganisms) on the surface of your skin. The result? Less inflammation and a stronger, healthier skin barrier—which can also mean less dryness, Dr. Lolis adds.5