Alphahydroxy

Alpha-hydroxy refers to a hydroxy group (–OH) attached to the carbon atom that is adjacent to a carbonyl group in a molecule. In common usage, compounds bearing both a hydroxy group and a carbonyl group at the alpha position are described as alpha-hydroxy compounds. The term is most widely encountered with alpha-hydroxy acids (AHAs), in which the hydroxy and carboxyl groups are on adjacent carbons, such as glycolic acid (hydroxyacetic acid) and lactic acid (2-hydroxypropanoic acid). AHAs are important in biochemistry, industry, and consumer products.

In organic chemistry, alpha-hydroxy ketones, aldehydes, and acids are reactive because the hydroxyl group sits next to a carbonyl. The alpha-hydroxy group can influence acidity, reactivity, and hydrogen bonding, and compounds of this class often serve as intermediates in synthesis, enabling transformations such as oxidation, dehydration, and various rearrangements. Alpha-hydroxy acids are frequently chiral, providing stereochemical handles for synthesis.

Industrial and cosmetic applications are notable. AHAs are widely used as exfoliants in skincare, helping to loosen dead skin cells and promote turnover. They appear in cleansers, toners, and chemical peels. In medicine and pharmacology, alpha-hydroxy acids serve as intermediates in the production of polymers, fragrances, and pharmaceutical agents.

Safety considerations include potential skin irritation and increased photosensitivity, especially at higher concentrations. Products containing AHAs are typically accompanied by sun protection recommendations and gradual introduction, particularly for individuals with sensitive skin or concurrent therapies.