Glycine is the simplest amino acid and is the only amino acid that is not optically active (it has no stereoisomers). This amino acid is essential for the biosynthesis of nucleic acids as well as of bile acids, porphyrins, creatine phosphate, and other amino acids. On a molar basis, glycine is the second most common amino acid found in proteins and enzymes being incorporated at the rate of 7.5 percent compared to the other amino acids. Glycine is also similar to gamma-aminobutyric acid and glutamic acid in the ability to inhibit neurotransmitter signals in the central nervous system.

Only the L form of amino acids are constituents of protein. Glycine is an important part of GTF (glucose tolerance factor). The prostate gland produces fluid that contains glycine and researchers think that it may have a positive influence on normal prostate function.

Glycine is a nonessential amino acid used by the body to build proteins. It is present in considerable amounts in prostate fluid. Glycine may play a role in maintaining the health of the prostate, since a study of 45 men with benign prostatic hyperplasia (BPH) found that 780 mg of glycine per day for two weeks and then 390 mg for the next two and a half months, taken in combination with equal amounts of the amino acids, alanine and glutamic acid, reduced symptoms of the condition. This effect has been reported by others. Glycine also enhances the activity of neurotransmitters (chemical messengers) in the brain that are involved in memory and cognition.

Healthy people do not need to supplement with glycine. A physician should be consulted before supplemental glycine is used for the support of serious health conditions.

Glycine is found in many foods high in protein, such as fish, meat, beans, and dairy.