Glycine is a conditionally dispensable amino acid that is synthesised from serine, with folate acting as a coenzyme (enzyme cofactor). Glycine gets its name from the Greek word meaning “sweet". It is an important precursor of many substances in the body, including protein, DNA, phospholipids, collagen and creatine. It is also a precursor in the release of energy and has been shown to increase growth hormone levels.
Glycine is also used by the liver in the elimination of toxic substances and in the formation of bile salts. It is necessary for the proper functioning of the central nervous system and is an inhibitory neurotransmitter.
During rapid growth, the body's demand for glycine increases. Studies have confirmed that the use of glycine supplements causes an increase in growth hormone. Some studies have also noted that glycine ingestion causes an increase in strength, possibly due in part to its elevation of the growth hormone level or increased collagen synthesis. Supplemental glycine has additionally been shown to increase body creatine levels.
Short-term use of 1-6 grams daily in divided dosages may be beneficial for power athletes and bodybuilders training for increased strength and muscle mass, as well as connective tissue repair and maintenance.
Like with all free-form amino acids, use glycine supplements with caution. In full profile amino acid products, glycine is typically contained in protein supplements and supplements that contain hydrolysed collagen and gelatine.