Glycine is the smallest of the 20 nonessential amino acids that make up the building blocks of plant and animal proteins. A sweet-tasting crystalline solid, glycine is the primary amino acid in sugar cane. In the body, it is found mainly in muscle tissue, connective tissue and skin. Glycine has several important functions in the body, including helping to regulate blood sugars by breaking glucose down into energy, helping to regulate the synthesis of bile acids to break down fats, and acting as an inhibitory neurotransmitter in the central nervous system, primarily in the spinal cord and brain stem where it acts as a transmitter of nerve impulses.

Abbreviated as Gly or G, glycine consists of an amino group and a carboxyl group attached to a carbon atom. It's a naturally-occurring organic compound with a chemical formula of NH₂CH₂COOH. The compound was first isolated in 1820 by Henri Braconnot, a French chemist and pharmacist who discovered this “gelatin sugar” by mixing gelatin with sulfuric acid and bringing it to a boil.

Glycine has a number of benefits. In addition to breaking down glucose and fats some research has shown that glycine can inhibit the neurotransmitters that cause biplor disorder, hyperactivity and seizures. It also plays an important role in the biosynthesis of heme, an important part of hemoglobin. As a result, it plays an essential role in maintaining both a healthy central nervous system and a healthy digestive system. It has also been thought to play an antioxidant role in protecting against some forms of cancer. Glycine’s effects can, however, be blocked with the chemical strychnine. Doing so can result in muscle spasms, arrested breathing, and seizures.

While it is essential for a healthy, functioning digestive system, and though it has other health benefits, it’s not an essential part of the human diet. This is because the human body can produce the compound on its own using two naturally-produced chemicals — serine and threonine. Glycine can also be manufactured synthetically, however, by treating chloroacetic acid with ammonia.

Dietary sources of glycine include high-protein foods such as meats, fish, dairy, and beans. Synthetically-produced supplements are available in the form of capsules or powders, and have been used to treat conditions such as schizophrenia, stroke, memory problems and prostate issues. These supplements are also commonly marketed to treat low energy and fatigue caused by hypoglycemia, anemia and chronic fatigue syndrome. Commercially, glycine has been used as an animal feed additive, as a sweetener/taste enhancer in food and beverage products, as a buffering agent in antacids and cosmetics, in fertilizers, and in solutions for irrigation.