Glycine is a structurally simple amino acid and one of the earliest to be isolated in 1820. Glycine is a nonessential amino acid for mammals, which means they can create it naturally from two other amino acids, serine and threonine.
Glycine contributes to:
- Human growth hormone production
- Prevention of sarcopenia (muscle wasting or deterioration)
- Sleep quality
- Mental performance and memory
- Protecting skin from the effects of aging
- Protecting collagen in joints
- Stabilizing blood sugar
Found in gelatin and silk, glycine functions as an inhibitory neurotransmitter in the central nervous system. Research suggests that animals on low-glycine diets show reduced growth. Though the body produced glycine, an average adult will ingest 3 to 5 grams daily from dietary sources.
Both naturally produced and ingested glycine are involved in the production of DNA, phospholipids, and collagen.
Joint Repair: Because of its role in collagen formation, glycine promotes joint, tendon, and ligament function and growth. Roughly 1/3 of collagen in the body is composed of glycine, and collagen is essential to the connective tissues that keep joints flexible and able to withstand shocks.
Muscle Growth: Glycine is used during the biosynthesis of creatine, which supplies muscles with the fuel required to repair damage and grow stronger. It also provides cells with energy by converting dietary nutrients to muscle tissues and may potentially boost endurance, strength and performance.
Glycine helps the body synthesize steroid hormones essential to regulating both fat-to-muscle ratio and energy expenditure.
Patients should avoid taking glycine if they are being treated with clozapine.
Some individuals have reported slight sedation after using glycine.
Anxiety: Glycine works together with other amino acids, including taurine and gamma-amino butyric acid (GABA), to act as an inhibitory neurotransmitter. This role has implications for sleep quality, mental performance, moods, memory, and behavior. Some evidence suggests that glycine may help reduce hyperactivity in the brain and may help treat and prevent certain mental disorders, such as learning disabilities, schizophrenia, bipolar disorder, and epilepsy. Other studies have demonstrated that glycine can reduce psychotic symptoms and seizures when used with other supplements.
Digestion: Amino acids like glycine rebuild the tissues that line the digestive tract, which helps keep bacteria and food particles inside the gut. Particles often exit through tiny openings and then pass into the bloodstream where they can trigger an inflammatory response. Glycine plays a role in forming collagen and gelatin, two important substances in the gut lining.
Glycine serves as a metabolic fuel inside the GI tract, and is required to produce bile, nucleic acids, creatine phosphate and the porphyrins used to break down nutrients. Glycine helps move glycogen to the cells for the production of ATP for energy. Studies show that glycine may help stabilize blood sugar levels, which can prevent food cravings and fatigue.
Aging: Glycine is involved in the production of glutathione, an antioxidant that prevents cell damage, oxidation and the effects of aging. Age leads to a distinct reduction in glutathione synthesis; supplementing the diet with the glutathione precursors cysteine and glycine can restore normal glutathione production.