Alpha-Hydroxy Acids (AHAs)

About 25 years before glycolic acid made its dramatic entry into the cosmetic skin care market in the early 1990s, lactic acid had been described as part of the skin’s NMF and was used with great success in skin moisturizers. In addition, Drs.Van Scott and Yu described the effectiveness of lactic acid in treating ichthyosis and disorders of keratinization. The combined use of topical retinoids as well as glycolic acid as an ingredient in cosmetic skin care products and in in-office peeling products has revolutionized the anti-aging skin care market [55].

The effects of alpha-hydroxy acids (AHAs) are determined by their pH and concentration levels. Although these naturally occurring organic acids are often referred to as fruit acids because they are found in many common fruits such as citrus fruits (citric acid), apples (malic acid), and grapes (tartaric acid), the two most widely used AHAs are not components of fruit. Glycolic acid is a sugar cane derivative, and lactic acid is derived from milk.

There have been a number of beauty benefits associated with the use of AHAs in facial skin care, and they have the ability to reduce the cohesion of dead corneocytes to the skin, giving the skin a smoother, less wrinkled, and less mottled appearance. It is ideal to couple these products with topical retinoids and lightening agents to enhance these effects. The effectiveness of AHAs in reversing the signs of aging were also coupled with problems of stinging, burning, and irritation, which were usually associated with a pH less than 3.5.