Isovaleric acid, 3-Methylbutanoic acid, 99.0+%

3-Methylbutanoic acid, or more commonly isovaleric acid, is an organic compound with the formula (CH3)2CHCH2CO2H. It is sometimes classified as a fatty acid. It is a colourless liquid that is sparingly soluble in water, but highly soluble in most common organic solvents. The compound occurs naturally, including in essential oils.

Isovaleric acid has a strong pungent cheesy or sweaty smell, but its volatile esters have pleasing scents and are used widely in perfumery. It has been proposed that it is the anticonvulsant agent in valerian. It is a major component of the cause of unpleasant foot odor, as it is produced by skin bacteria metabolizing leucine.