DL-Methionine is an essential amino acid containing sulphur. Methionine consists of an asymmetric carbon and exists as D (dextrogyre) and L (levogyre) optical isomers. The L-methionine is considered as biologically active. The racemic mixture of D and L-isomers forms DL-methionine, which is the commercially available methionine.

DL-Methionine has been used to study its effect on the growth and feed utilization of Nile tilapia. It has also been used as a part of standard diet in animal models.

DL-Methionine is an amino acid that has a role in the defence of oxidative stress.

Methionine offers protection against disorders related to hair, skin and nails. It elevates lecithin production in the liver and thereby reduces cholesterol level. It naturally serves as a heavy metal chelating agent, regulating ammonia concentration in the urine. This ameliorates bladder irritation. Methionine is also known to induce hair growth.