3-Hydroxypropionic acid, a simple beta hydroxy acid

A beta hydroxy acid (BHA) is an organic compound which contains a carboxylic acid functional group and hydroxy functional group separated by two carbon atoms. They are closely related to alpha hydroxy acids, in which the two functional groups are separated by one carbon atom.

In cosmetics, the term beta hydroxy acid refers specifically to salicylic acid, which is used in some "anti-aging" creams and acne treatments.

Other beta hydroxy acids include:

• Beta-hydroxybutyric acid
• Beta-hydroxy beta-methylbutyrate
• Carnitine
• 3-Hydroxypropionic acid