Alpha hydroxy acid (AHA) extracted from milk, although most forms used in cosmetics are synthetic because that form is easier to formulate with and stabilize. In a pH-correct formula, lactic acid exfoliates cells on the surface of skin by breaking down the material that holds skin cells together. It may irritate mucous membranes and cause irritation, although this isn’t common. Lactic acid also has water-binding properties and, like glycolic acid (another AHA), may help lighten skin discolorations. [1,2]
- Babilas P, Knie U, Abels C. Cosmetic and dermatologic use of alpha hydroxy acids. J Dtsch Dermatol Ges. 2012;10(7):488-91.
- Loden M. Role of topical emollients and moisturizers in the treatment of dry skin barrier disorders. Am J Clin Dermatol. 2003;4(11):771-88.