Figure 1.

The structures of AHAs commonly used in dermatology including glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid. AHAs are weak organic acids with one or more hydroxyl group attached to the alpha carbon, indicating α. Malic acid and citric acid contain a hydroxyl group in the α-position to one carboxyl group and in the β-position to the other carboxyl group. Tartaric acid is a dicarboxylic acid with two hydroxyl groups at the alpha position of the acid. Malic acid and citric acid are also prominent representatives in alpha hydroxyl acids and beta hydroxyl acids.