Octadecanoic acid is a C18 straight-chain saturated fatty acid component of many animal and vegetable lipids. As well as in the diet, it is used in hardening soaps, softening plastics and in making cosmetics, candles and plastics. It has a role as a plant metabolite, a human metabolite, a Daphnia magna metabolite and an algal metabolite. It is a long-chain fatty acid, a saturated fatty acid and a straight-chain saturated fatty acid. It is a conjugate acid of an octadecanoate. It derives from a hydride of an octadecane.
