Glycine (symbol Gly or G; /ˈɡlaɪsiːn/) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest amino acid, with the chemical formula NH2‐CH2‐COOH. Glycine is one of the proteinogenic amino acids. It is encoded by all the codons starting with GG (GGU, GGC, GGA, GGG). Glycine is integral to the formation of alpha-helices in secondary protein structure due to its compact form. For the same reason, it is most abundant amino acid in collagen triple-helices. Glycine is also an inhibitory neurotransmitter – interference with its release within the spinal cord (such as during a Clostridium tetani infection) can cause spastic paralysis due to uninhibited muscle contraction.
Glycine is a colorless, sweet-tasting crystalline solid. It is the only achiral proteinogenic amino acid. It can fit into hydrophilic or hydrophobic environments, due to its minimal side chain of only one hydrogen atom. The acyl radical is glycyl.
Glycine is an amino acid, a building block for protein. It is not considered an “essential amino acid” because the body can make it from other chemicals.
Glycine is an inhibitory neurotransmitter in the central nervous system, especially in the spinal cord, brainstem, and retina.
Most of the current research has been focused on its role in the central nervous system, where it may be able to improve sleep, enhance memory, and aid in the treatment of schizophrenia.
It is also believed to reduce brain damage following a stroke, treat an enlarged prostate, heal serious leg ulcers, and improve insulin sensitivity in people with diabetes or prediabetes.
Leg ulcers. Applying cream containing glycine and other amino acids seems to reduce pain and slightly improve the healing of leg ulcers.
Schizophrenia. Taking glycine by mouth along with conventional medicines seems to reduce negative symptoms of schizophrenia in some people who don’t respond to treatment with conventional medicines alone.
Treating the most common form of stroke (ischemic stroke). Putting glycine under the tongue may help to limit brain damage caused by an ischemic stroke when started within 6 hours of having the stroke. An ischemic stroke is caused by the blockage of a blood vessel (usually by a clot) in the brain. Brain cells beyond the obstruction don’t receive oxygen and begin to die, causing irreversible damage.