Alpha-hydroxy is a chemical compound derived from fruit and milk sugars. Alpha-hydroxy acids (AHAs) are used in topical skin care products to exfoliate, or slough away, dead skin cells and promote collagen growth.

They may be useful in promoting smoother, even-toned skin and may reduce the appearance of wrinkles and fine lines in some individuals. Products containing AHA may be used to treat acne, age spots, and other irregular skin pigmentations.

AHAs are available in a number of different synthetic and natural formulations. Lactic AHA is derived from milk products, while glycolic AHA is derived from sugarcane. Other AHA compounds include citric acid derived from citrus fruit, malic acid derived from apples, and tartaric acid derived from grapes.

AHAs work by removing dead cells at the surface of the skin. In higher concentrations, alpha hydroxy promotes collagen production, which may reduce the appearance of fine lines and wrinkles in the skin. The acids penetrate deep into the skin, where they actually begin to damage skin cells.

This skin damage triggers the production of collagen, a fibrous protein and a building block of tissue and skin, as the body attempts to repair the cell damage. AHA may be an ingredient in over-the-counter products such as creams, lotions, and moisturizers that are marketed for their supposed anti-aging properties.

Among the uses of products containing AHA are to smooth fine lines and surface wrinkles, unblock or open pores, improve overall skin appearance and conditions, including acne and oily skin. Over-the counter products generally have an AHA concentration of 10% or less.

AHA may also be used in chemical peels used to treat skin conditions such as wrinkles, acne, scarring, and oily skin. The concentration of AHA products used by trained cosmetologists may run between 20% and 30%, while those used by doctors may range from 50% to 70%.