Lactic Acid Benefits
- Gently resurfaces skin
- Hydrates while exfoliating
- Supports collagen & elastin
- Smooths rough texture
Lactic Acid Description
Milk is the natural source of lactic acid, but the version used in most skincare today comes from a non dairy fermentation process instead. The result is chemically identical to naturally occurring lactic acid, just easier to formulate with, and it's fully vegan.
As an alpha hydroxy acid, lactic acid exfoliates by loosening the bonds between dead skin cells so they shed the way they would naturally, provided the formula sits at the right pH, generally 3 to 4, and a concentration of 5% to 12%. It doubles as a hydrator too. One of its byproducts, sodium lactate, is actually a natural building block of skin's own moisture holding system.
Its benefits don't stop at exfoliating and hydrating. Lactic acid also encourages the skin to produce more ceramides, which strengthens the barrier, and it appears to support a healthy skin microbiome, in part by interacting positively with Substance P, a neuropeptide involved in how skin signals and recovers from stress. Like glycolic acid, another common AHA, it can also help fade dullness and even out skin tone over time.
Lactic Acid References
International Journal of Cosmetic Science, April 2020, pages 116-126 | International Journal of Dermatology, March 2019, ePublication | Clinical, Cosmetic, and Investigational Dermatology, October 2018, pages 491-497 | International Journal of Dermatology, September 2018, ePublication | Molecules, April 2018, ePublication | Journal of the American Dental Association, April 2016, pages 255-263 | Cutis, January 2016, pages E9-E11 | Clinical, Cosmetic, and Investigational Dermatology, November 2010, pages 135-142 | The Journal of Dermatology, January 2006, pages 16-22
Written by Elle Layne
Ingredient Ratings
Our team reviews ingredient research and uses up-to-date evidence to rate ingredients based on the categories below.
Best
Ingredients with the most rigorous and convincing evidence. These are the standouts backed by consistent findings across independent, peer reviewed clinical research.. When we call an ingredient Best, it has earned that distinction through genuine, reproducible proof that it improves skin.
Good
Reliable, well tolerated ingredients that do their job without complaint. They may not carry the headline benefits of a Best rated active, but they hydrate, stabilize a formula, or support the ingredients around them in ways that make a real difference in how a product performs and feels.
Average
Ingredients that are perfectly safe and serve a clear function, typically as an emollient, thickener, or filler, but do not offer any meaningful skin benefit beyond that basic job. Not a red flag, just not a reason to choose one product over another.
Bad/Worst
Ingredients with documented potential to irritate skin, disrupt the barrier, or trigger sensitization in some users, often synthetic fragrance, drying forms of alcohol, or certain essential oils. Not automatically a dealbreaker for every skin type, but worth knowing about before you commit to a product.