Isobutyric acid is a branched fatty acid comprising propanoic acid carrying a methyl branch at C-2. It has a role as a volatile oil component, a plant metabolite and a Daphnia magna metabolite. It is a branched-chain saturated fatty acid, a methyl-branched fatty acid and a fatty acid 4:0. It is a conjugate acid of an isobutyrate. Experimental spectrum in Natural Products Magnetic Resonance Database: [NP0000989](https://np-mrd.org/natural_products/562/submission_spectrum_view?spectrum_id=350&spectrum_type=real)