Lactic acid is one of the most popular alpha hydroxy acids (AHAs) in skin care today, marketed as a powerful ingredient that helps reduce acne breakouts and the appearance of wrinkles and other signs of aging. Lactic acid is a natural acid derived from milk, fruit, vegetables and other plants. It’s found in over-the-counter skin care products used for anti-aging, and is also used in chemical peels. With a reputation for being gentler and less irritating than glycolic acid, it also hydrates, increases natural barrier lipids in the outer layer of skin, and lightens and brightens skin for those with age spots or darkened areas. Mainly, however, lactic acids and other AHAs are used to exfoliate the outer layer of skin, helping to reveal a softer, younger looking complexion, and speeding up the rate of cell turnover.