Hydroxybutyric acid is a group of four-carbon organic compounds that have both hydroxyl and carboxylic acid functional groups.
[1] They can be viewed as derivatives of butyric acid.
The carboxylate anion and the esters of hydroxybutyric acids are known as hydroxybutyrates.
β-hydroxybutyric acid is relevant to human health as it is a member of a class of products of fatty acid oxidation referred to as ketone bodies.
The isomers are distinguished by the distance between the two functional groups and the branching.