Glycine
This article provides general nutrition information only and is not medical advice.

Overview
Glycine is an amino acid, or a building block for protein. The body can make glycine on its own, but it is also consumed in the diet. A typical diet contains about 2 grams of glycine daily. The primary sources are protein-rich foods including meat, fish, dairy, and legumes. Glycine can also be taken as a supplement.
Glycine is used for schizophrenia, stroke, and memory and thinking skills (cognitive function), but there is no good scientific evidence to support these uses.
Classification
Is a Form of:
Amino acid
Primary Functions:
Schizophrenia, stroke, memory and thinking skills
Also Known As:
Aminoacetic Acid, Athenon, Free Base Glycine, G Salt, Glicina
How Does It Work?
The body uses glycine to make proteins. Glycine is also involved in the transmission of chemical signals in the brain, so there is interest in trying it for schizophrenia and improving memory. Some researchers think glycine may have a role in cancer prevention because it seems to interfere with the blood supply needed by certain tumors.
Uses
- Schizophrenia. Taking glycine by mouth along with conventional medicines seems to reduce certain concerns of schizophrenia, called negative concerns, in some people who don't respond to nutritional support with conventional medicines.
- Stroke. Taking glycine under the tongue for 5 days may help to reduce brain damage due to a stroke that was caused by the blockage of a blood vessel (usually by a clot) in the brain.
Recommended Dosing
The following doses have been studied in scientific research:
BY MOUTH:
- For schizophrenia: Glycine has been used in doses ranging from 0.4-0.8 grams/kg daily in divided doses. It is usually started at 4 grams daily and increased by 4 grams per day until the effective dose is reached.
UNDER THE TONGUE:
- For stroke: 1 to 2 grams per day started within 6 hours after stroke onset has been used.
Glycine Supplements Frequently Asked Questions
What are glycine supplements used for?
Glycine is used for treating schizophrenia, stroke, benign prostatic hyperplasia (BPH), and some rare inherited metabolic imbalances. It is also used to protect kidneys from the harmful side effects of certain drugs used after organ transplantation as well as the liver from harmful effects of alcohol.
Is it safe to take glycine?
Glycine appears to be safe, even at doses of up to 9 grams for 3 days. People being treated with clozapine should avoid taking glycine. Also people who have had a stroke should not take glycine without the supervision of a doctor. A few people have reported nausea, vomiting, and upset stomach after taking glycine.
Does glycine make you sleepy?
Research shows oral glycine elevates serotonin, reduces concerns of sleep quality, and improves sleep quality. Other studies suggest it may help you bounce back to healthy sleep cycles after a period of disrupted sleep.
When should I take glycine?
It is recommended to take glycine with a meal before bed, as taking glycine on an empty stomach can sometimes cause nausea. Because of its sedative-like effects on sleep, it's more helpful before bed than in the morning or midday.
Who should not take glycine?
Glycine appears to be safe, even at doses of up to 9 grams for 3 days. But glycine's safety has not been fully tested or studied. Particular caution should be taken when considering glycine for young children, pregnant or breastfeeding women, and people with liver or kidney condition.
Which foods are high in glycine?
This amino acid is found in high-protein foods including meat, fish, eggs, dairy and legumes. A daily diet typically includes about 2 grams of glycine.
Is glycine bad for kidneys?
Glycine also ameliorated the raise in urinary malondialdehyde (MDA) levels and partially restored renal glutathione levels in diabetic rats. Renal levels of the Nox4 mRNA and protein, a major source of renal oxidative stress, were suppressed by the nutritional support with glycine.
Does glycine help stress?
When an individual experiences stress or panic, NE is released and creates feelings of stress and panic. Glycine antagonizes the release of NE, thus mitigating stress and panic and feelings of over-arousal.
How long before bed should I take glycine?
The studies done in humans have usually used three grams of glycine. This was typically provided around 1 - 2 hours before bed. While glycine can be found in capsule form and bought over the counter, it may provide additional benefits when paired with other nootropic ingredients.
Can I take glycine everyday?
Supplementing with glycine is safe in appropriate amounts. Studies have used up to 90 grams of glycine per day over several weeks without serious side effects. For comparison, the standard dose used in studies is about 3–5 grams per day.
Does glycine increase serotonin?
Among other things, serotonin is required to make the sleep hormone melatonin. Research shows oral glycine elevates serotonin, reduces concerns of sleep quality, and improves sleep quality.
Can you take glycine and magnesium together?
Magnesium + Glycinate are the The Perfect Pair
Magnesium glycinate is an organic magnesium salt created by combining magnesium with the amino acid, glycine. Combine one sleep-improving mineral salt with a sleep-improving amino acid and you get—a sleep improving supplement.
What are the side effects of glycine?
Glycine is POSSIBLY SAFE for most people when taken by mouth or applied to the skin. Most people do not experience side effects, although there have been a few reports of gastrointestinal side effects such as soft stools, nausea, vomiting, and stomach upset.
Does glycine raise blood sugar?
Ingestion of glycine reduces blood glucose levels (18), and it was suggested that glycine was stimulating insulin secretion in humans. Although physiological glycine (300 μmol/L) only tended to increase insulin secretion, glycine at 800 μmol/L significantly increased insulin secretion.
What causes glycine deficiency?
Glycine encephalopathy is caused by changes (mutations) in the AMT, GLDC or GCSH genes which result in a deficiency of the enzyme that break-up the glycine. Diagnosis is based in the concerns, the high glycine levels and the enzyme deficiency, as well as genetic testing. Inheritance is autosomal recessive.
Does glycine spike insulin?
The serum insulin concentration also was slightly elevated after the ingestion of glycine alone. When glycine was ingested with glucose, the plasma glucose area response was attenuated by >50% compared with the response after the ingestion of glucose alone.
How do I lower my glycine levels?
Sodium benzoate is used to reduce serum glycine levels. Benzoate binds to glycine in the body to form hippurate, which is excreted in the urine. This nutritional support reduces seizures and improves alertness. Plasma glycine levels must be monitored closely to ensure sodium benzoate is at an effective and non-toxic level.
Does glycine increase GABA?
Inhibition of GABA breakdown causes a rise in tissue GABA content and an increase in the activity of inhibitory neurons. About half of the inhibitory synapses in the spinal cord use glycine; most other inhibitory synapses use GABA.
Does glycine build muscle?
As an amino acid, glycine works as a protein builder in the body. In particular, glycine enables the production of collagen, a protein that is an essential component of muscles, tendon, skin, and bones. Collagen is the most commonly occurring protein in the body, comprising roughly a third of all body protein.
Clinical Studies
- ^ a b c Wang W, et al. Glycine metabolism in animals and humans: implications for nutrition and health. Amino Acids. (2013)
- ^ Lodish H, Berk A, Zipursky SL. Section 22.3, Collagen: The Fibrous Proteins of the Matrix. Molecular Cell Biology. 4th edition. (2000)
- ^ a b Shoulders MD, Raines RT. Collagen structure and stability. Annu Rev Biochem. (2009)
- ^ a b c d e f Meléndez-Hevia E, et al. A weak link in metabolism: the metabolic capacity for glycine biosynthesis does not satisfy the need for collagen synthesis. J Biosci. (2009)
- ^ National Center for Biotechnology Information. Glycine. PubChem Compound Database.
- ^ Gajko-Galicka A. Mutations in type I collagen genes resulting in osteogenesis imperfecta in humans. Acta Biochim Pol. (2002)
- ^ Yan BX, Sun YQ. Glycine residues provide flexibility for enzyme active sites. J Biol Chem. (1997)
- ^ Myllyharju J, Kivirikko KI. Collagens and collagen-related conditions. Ann Med. (2001)
- ^ Layer G, et al. Structure and function of enzymes in heme biosynthesis. Protein Sci. (2010)
- ^ Brosnan JT, da Silva RP, Brosnan ME. The metabolic burden of creatine synthesis. Amino Acids. (2011)
- ^ Lu SC. Glutathione synthesis. Biochim Biophys Acta. (2013)
- ^ Berg JM, Tymoczko JL, Stryer L. Section 25.2, Purine Bases Can Be Synthesized de Novo or Recycled by Salvage Pathways. Biochemistry. 5th edition. (2002)
- ^ Vessey DA. The biochemical basis for the conjugation of bile acids with either glycine or taurine. Biochem J. (1978)
- ^ Zafra F, Giménez C. Glycine transporters and synaptic function. IUBMB Life. (2008)
- ^ Betz H, Laube B. Glycine receptors: recent insights into their structural organization and functional diversity. J Neurochem. (2006)
- ^ Johnson JW, Ascher P. Glycine potentiates the NMDA response in cultured mouse brain neurons. Nature. (1987)
- ^ Gomeza J, et al. Lessons from the knocked-out glycine transporters. Handb Exp Pharmacol. (2006)
- ^ Zhong Z, et al. L-Glycine: a novel joint comfort, immunomodulatory, and cytoprotective agent. Curr Opin Clin Nutr Metab Care. (2003)
- ^ a b Melendez-Hevia E, Paz-Lugo PD. Branch-point stoichiometry can generate weak links in metabolism: the case of glycine biosynthesis. J Biosci. (2008)
- ^ Lamers Y, et al. Glycine turnover and decarboxylation rate quantified in healthy men and women using primed, constant infusions of 1,2-(13)C2glycine and (2)H3leucine. J Nutr. (2007)
- ^ Yu YM, et al. Quantitative aspects of glycine and alanine nitrogen metabolism in postabsorptive young men: effects of level of nitrogen and dispensable amino acid intake. J Nutr. (1985)
- ^ Gersovitz M, et al. Dynamic aspects of whole body glycine metabolism: influence of protein intake in young adult and elderly males. Metabolism. (1980)
- ^ Cornish-Bowden A, Pereto J, Cardenas ML. Biochemistry and evolutionary biology: two disciplines that need each other?. J Biosci. (2014)
- ^ Greer M, Greer JK, Gillingham J. Osteoarthritis in selected wild mammals. Proc Okla Acad Sci. (1977)
- ^ Weissengruber GE, et al. The elephant knee joint: morphological and biomechanical considerations. J Anat. (2006)
- ^ Wallach JD. Degenerative arthritis in a black rhinoceros. J Am Vet Med Assoc. (1967)
- ^ Jurmain R. Degenerative joint condition in African great apes: an evolutionary perspective. J Hum Evol. (2000)
- ^ STRAUS WL Jr, CAVE JE. Pathology and the posture of Neanderthal man. Q Rev Biol. (1957)
- ^ Li P, Wu G. Roles of dietary glycine, proline, and hydroxyproline in collagen synthesis and animal growth. Amino Acids. (2018)
- ^ Ames BN. Low micronutrient intake may accelerate the degenerative conditions of aging through allocation of scarce micronutrients by triage. Proc Natl Acad Sci U S A. (2006)
- ^ de Paz-Lugo P, Lupiáñez JA, Meléndez-Hevia E. High glycine concentration increases collagen synthesis by articular chondrocytes in vitro: acute glycine deficiency could be an important cause of osteoarthritis. Amino Acids. (2018)
- ^ Mayatepek E. 5-Oxoprolinuria in patients with and without defects in the gamma-glutamyl cycle. Eur J Pediatr. (1999)
- ^ Jackson AA, et al. Urinary excretion of 5-oxoproline (pyroglutamic aciduria) as an index of glycine insufficiency in normal man. Br J Nutr. (1987)
- ^ Metges CC, et al. Oxoproline kinetics and oxoproline urinary excretion during glycine- or sulfur amino acid-free diets in humans. Am J Physiol Endocrinol Metab. (2000)
- ^ Persaud C, Forrester T, Jackson AA. Urinary excretion of 5-L-oxoproline (pyroglutamic acid) is increased during recovery from severe childhood malnutrition and responds to supplemental glycine. J Nutr. (1996)
- ^ McCarty MF, O'Keefe JH, DiNicolantonio JJ. Dietary Glycine Is Rate-Limiting for Glutathione Synthesis and May Have Broad Potential for Health Protection. Ochsner J. (2018)
- ^ Lord RS. Long-term patterns of urinary pyroglutamic acid in healthy humans. Physiol Rep. (2016)
- ^ Jackson AA, et al. Urinary excretion of 5-L-oxoproline (pyroglutamic acid) is increased in normal adults consuming vegetarian or low protein diets. J Nutr. (1996)
- ^ Jackson AA, et al. Urinary excretion of 5-L-oxoproline (pyroglutamic acid) during early life in term and preterm infants. Arch Dis Child Fetal Neonatal Ed. (1997)
- ^ Jackson AA, et al. Nitrogen metabolism in preterm infants fed human donor breast milk: the possible essentiality of glycine. Pediatr Res. (1981)
- ^ Nair AB, Jacob S. A simple practice guide for dose conversion between animals and human. J Basic Clin Pharm. (2016)
- ^ Shoham S, Javitt DC, Heresco-Levy U. High dose glycine nutrition affects glial cell morphology in rat hippocampus and cerebellum. Int J Neuropsychopharmacol. (1999)
- ^ Shoham S, Javitt DC, Heresco-Levy U. Chronic high-dose glycine nutrition: effects on rat brain cell morphology. Biol Psychiatry. (2001)
- ^ Bacci G, et al. Long-term results in 144 localized Ewing's sarcoma patients treated with combined routine. Cancer. (1989)
- ^ Heresco-Levy U, et al. Double-blind, placebo-controlled, crossover trial of glycine adjuvant routine for nutritional support-resistant schizophrenia. Br J Psychiatry. (1996)
- ^ Heresco-Levy U, et al. Efficacy of high-dose glycine in the nutritional support of enduring negative concerns of schizophrenia. Arch Gen Psychiatry. (1999)
- ^ Javitt DC, et al. Adjunctive high-dose glycine in the nutritional support of schizophrenia. Int J Neuropsychopharmacol. (2001)
- ^ Cleveland WL, et al. High-dose glycine nutritional support of refractory obsessive-compulsive imbalance and body dysmorphic imbalance in a 5-year period. Neural Plast. (2009)
- ^ Attobla MHBE. Glycine supplementation to improve insulin sensitivity in humans. PhD diss., University of Alabama at Birmingham. (2014)
- ^ Inagawa K, et al. Assessment of acute adverse events of glycine ingestion at a high dose in human volunteers. SEIKATSU EISEI (Journal of Urban Living and Health Association). (2006)
- ^ a b Silk DB, Grimble GK, Rees RG. Protein digestion and amino acid and peptide absorption. Proc Nutr Soc. (1985)
- ^ NEWEY H, SMYTH DH. THE TRANSFER SYSTEM FOR NEUTRAL AMINO ACIDS IN THE RAT SMALL INTESTINE. J Physiol. (1964)
- ^ Munck BG. Amino acid transport by the small intestine of the rat. The existence and specificity of the transport mechanism of imino acids and its relation to the transport of glycine. Biochim Biophys Acta. (1966)
- ^ Thwaites DT, Anderson CM. Deciphering the mechanisms of intestinal imino (and amino) acid transport: the redemption of SLC36A1. Biochim Biophys Acta. (2007)
- ^ Rubino A, Field M, Shwachman H. Intestinal transport of amino acid residues of dipeptides. I. Influx of the glycine residue of glycyl-L-proline across mucosal border. J Biol Chem. (1971)
- ^ Adibi SA, Soleimanpour MR. Functional characterization of dipeptide transport system in human jejunum. J Clin Invest. (1974)
- ^ a b Rajendran VM, et al. Transport of glycyl-L-proline by human intestinal brush border membrane vesicles. Gastroenterology. (1985)
- ^ Silk DB, et al. Functional differentiation of human jejunum and ileum: a comparison of the handling of glucose, peptides, and amino acids. Gut. (1974)
- ^ a b Craft IL, et al. Absorption and malabsorption of glycine and glycine peptides in man. Gut. (1968)
- ^ a b c Gannon MC, Nuttall JA, Nuttall FQ. The metabolic response to ingested glycine. Am J Clin Nutr. (2002)
- ^ Gulliford MC, et al. Intestinal glucose and amino acid absorption in healthy volunteers and noninsulin-dependent diabetic subjects. Am J Clin Nutr. (1989)
- ^ Cook GC. Increased glycine absorption rate associated with acute bacterial immune challenges in man. Br J Nutr. (1973)
- ^ Cook GC. Effect of systemic immune challenges on glycylglycine absorption rate from the human jejunum in vivo. Br J Nutr. (1974)
- ^ Cook GC. Impairment of glycine absorption by glucose and galactose in man. J Physiol. (1971)
- ^ Cook GC. Effect of intraluminal concentrations on the impairment of glycine adsorption by glucose in the human jejunum. Clin Sci. (1972)
- ^ Cook GC. Comparison of intestinal absorption rates of glycine and glycylglycine in man and the effect of glucose in the perfusing fluid. Clin Sci. (1972)
- ^ Alvarado F, Robinson JW. A kinetic study of the interactions between amino acids and monosaccharides at the intestinal brush-border membrane. J Physiol. (1979)
- ^ Cook GC. Some factors influencing absorption rates of the digestion products of protein and carbohydrate from the proximal jejunum of man and their possible nutritional implications. Gut. (1974)
- ^ Matthews DE, et al. Glycine nitrogen metabolism in man. Metabolism. (1981)
- ^ Kikuchi G, et al. Glycine cleavage system: reaction mechanism, physiological significance, and hyperglycinemia. Proc Jpn Acad Ser B Phys Biol Sci. (2008)
- ^ Conter C, et al. Genetic heterogeneity of the GLDC gene in 28 unrelated patients with glycine encephalopathy. J Inherit Metab Dis. (2006)
- ^ Jois M, et al. Regulation of hepatic glycine catabolism by glucagon. J Biol Chem. (1989)
- ^ Lowry M, Hall DE, Brosnan JT. Increased activity of renal glycine-cleavage-enzyme complex in metabolic acidosis. Biochem J. (1985)
- ^ Aragón C, López-Corcuera B. Glycine transporters: crucial roles of pharmacological interest revealed by gene deletion. Trends Pharmacol Sci. (2005)
- ^ a b c Betz H, et al. Glycine transporters: essential regulators of synaptic transmission. Biochem Soc Trans. (2006)