Table of Contents
General Information
Glycine is, structurally, the simplest amino acid that has been discovered. It was one of the earliest amino acids to be isolated from gelatin back in 1820. Glycine is one of the nonessential amino acids for mammals; meaning that they can create it internally from two other amino acids: serine and threonine (1).
Glycine is found principally in gelatin and silk fibroin. It’s been used therapeutically as a nutrient, and also functions as a rapid inhibitory neurotransmitter in the central nervous system (CNS) (2). Although glycine is both a simple and nonessential amino acid; experimental animals on low-glycine diets show reduced growth (1, 2). The average adult will ingest 3 to 5 grams of glycine daily from dietary sources (1). Glycine is an amino acid that’s involved in the production of DNA, phospholipids, and collagen. It’s also involved in the release of energy (3).
Glycine for Joint Repair
Glycine plays a vital role in collagen formation. It’s an important component for promoting joint, tendon, and ligament function and growth (4). Roughly 1/3 of collagen in the body is composed of glycine, and collagen is critical for the formation of the connective tissues that keep joints flexible and capable of successfully withstanding shocks (5).
Glycine and muscle growth: The body uses glycine during the biosynthesis of creatine; which supplies all muscles with a source of fuel to repair damage and grows stronger (6). It also provides cells with energy due to its role in converting dietary nutrient to help feed muscle tissues and boost:
• Endurance
• Strength
• Performance
Glycine also benefits hormone production and regulation. It helps the body to naturally synthesize steroid hormones essential to regulating both the fat to muscle ratio and controlling energy expenditure (7).
Can have a Calming Effect on The Brain
Glycine will work with other amino acids, including taurine and gamma-aminobutyric acid (GABA), to act as an inhibitory neurotransmitter (8). This role in nerve and neurotransmitter functions has implications for improving; sleep quality, mental performance, moods, memory, and behavior. Some evidence suggests that glycine may help reduce hyperactivity in the brain and play an effective role in the treatment and prevention of certain mental disorders, such as learning disabilities, schizophrenia, bipolar disorder, and epilepsy (8). Other studies have demonstrated that glycine can help minimize psychotic symptoms and seizures when used with other supplements as part of a treatment plan for neurological illness (9, 10).
Assists Digestion
Amino acids, including glycine, help to rebuild the tissue that lines the digestive tract (11); keeping bacteria and food particles contained inside the gut, rather than exiting through tiny openings that pass this matter into the bloodstream where it can trigger an inflammatory response (12,13)). Glycine plays a role in forming the two most important substances in the gut lining: collagen and gelatin (12, 13).
Inside the GI Tract
glycine will be utilized as a metabolic fuel (14). It’s required in the production of bile (to break down fats), nucleic acids, creatine phosphate and the porphyrins used to break down nutrients (15). It helps move glycogen to the cells for the production of ATP for energy (15). Studies show that glycine may help stabilize blood sugar levels, preventing food cravings and fatigue (16).
Aging
Glycine is used to produce glutathione, an antioxidant that prevents cell damage and several signs of aging. A paper published in the American Journal of Clinical Nutrition concluded that, while glutathione deficiency in the elderly occurs because of a distinct reduction in glutathione synthesis, supplementing the diet with the glutathione precursors cysteine (NAC) and glycine completely restore normal glutathione production (17).
What is this supplement used for? Glycine plays a role in:
- The production of human growth hormone (18)
- Preventing sarcopenia (muscle wasting or deterioration) (19)
- Improving sleep quality (19)
- Mental performance and memory (9, 10)
- Protecting skin from signs of aging (17)
- Protecting collagen in joints and reducing joint pain (5)
- Boosting energy levels (15)
- Stabilizing blood sugar (16)
Who shouldn’t take this supplement? Due to a lack of studies on the safety of glycine during pregnancy and breastfeeding it would be best for women who are pregnant or nursing to avoid using it.
What are the precautions when taking this supplement? People being treated with clozapine should avoid taking glycine (20).
What are some possible side effects of this supplement? A small number of individuals have reported experiencing slight sedation after using glycine (21).
How is it best taken? Glycine can be taken either orally or by intramuscular injection.
What do I do if I miss a dose? If you do miss a dose; it’s best to take it as soon as you remember. Although, if it’s almost time for the next dose, just skip the missed one and take your next scheduled dose. Don’t take two doses at the same time.
How should I store this supplement? Store glycine at between 68°F to 77°F (20°C to 25°C) and keep it away from heat, moisture, and light. Keep all medicines out of the reach of children. Throw away any unused medicine after the expiration date. Do not flush unused medications or pour down a sink or drain.
General Statements
Do not share or take anyone else's medicine. Talk with your healthcare provider before starting any new medicine, including over-the-counter, natural products, or vitamins. This patient information summarizes the most important information about your medication; if you would like more information, talk with your doctor.
1) https://www.calstatela.edu/sites/default/files/dept/chem/07summer/158/25-words-glycine.pdf
2) National Center for Biotechnology Information. PubChem Compound Database; CID=750, https://pubchem.ncbi.nlm.nih.gov/compound/750 (accessed Oct. 6, 2017).
3) Guo, Zhi-li et al. “DanHong Injection Dose-Dependently Varies Amino Acid Metabolites and Metabolic Pathways in the Treatment of Rats with Cerebral Ischemia.” Acta Pharmacologica Sinica 36.6 (2015): 748–757. PMC. Web. 6 Oct. 2017.
4) Yang, Guang, Benjamin B. Rothrauff, and Rocky S. Tuan. “Tendon and Ligament Regeneration and Repair: Clinical Relevance and Developmental Paradigm.” Birth defects research. Part C, Embryo today?: reviews 99.3 (2013): 203–222. PMC. Web. 6 Oct. 2017.
5) Alfonso E. Bello & Steffen Oesser.Current Medical Research and Opinion Vol. 22, Iss. 11,2006
6) Da Silva, Robin P. et al. “Creatine Synthesis: Hepatic Metabolism of Guanidinoacetate and Creatine in the Rat in Vitro and in Vivo.” American Journal of Physiology - Endocrinology and Metabolism 296.2 (2009): E256–E261. PMC. Web. 6 Oct. 2017.
7) Arwert LI, Deijen JB, Drent ML. Effects of an oral mixture containing glycine, glutamine and niacin on memory, GH and IGF-I secretion in middle-aged and elderly subjects. Nutr Neurosci. 2003 Oct;6(5):269-75.
8) Bowery, N G, and T G Smart. “GABA and Glycine as Neurotransmitters: A Brief History.” British Journal of Pharmacology 147.Suppl 1 (2006): S109–S119. PMC. Web. 6 Oct. 2017.
9) Shen, Hai-Ying et al. “Glycine Transporter 1 Is a Target for the Treatment of Epilepsy.” Neuropharmacology 99 (2015): 554–565. PMC. Web. 6 Oct. 2017.
10) Algon, Sibel et al. “Evaluation and Treatment of Children and Adolescents with Psychotic Symptoms.” Current psychiatry reports 14.2 (2012): 101–110. PMC. Web. 6 Oct. 2017.
11) Ruth, Megan R, and Catherine J Field. “The Immune Modifying Effects of Amino Acids on Gut-Associated Lymphoid Tissue.” Journal of Animal Science and Biotechnology 4.1 (2013): 27. PMC. Web. 6 Oct. 2017.
12) Li P, Wu G. Roles of dietary glycine, proline, and hydroxyproline in collagen synthesis and animal growth. Amino Acids. 2017 Sep 20. doi: 10.1007/s00726-017-2490-6. [Epub ahead of print].
13) Ruth and Field; licensee BioMed Central Ltd. 2013. Journal of Animal Science and Biotechnology20134:27 https://doi.org/10.1186/2049-1891-4-27.
14) Wang WW, Qiao SY, Li DF. Amino acids and gut function. Amino Acids. 2009 May;37(1):105-10. doi: 10.1007/s00726-008-0152-4. Epub 2008 Aug 1.
15) Sheth, H., Hafez, T., Glantzounis, G. K., Seifalian, A. M., Fuller, B. and Davidson, B. R. (2011), Glycine maintains mitochondrial activity and bile composition following warm liver ischemia-reperfusion injury. Journal of Gastroenterology and Hepatology, 26: 194–200. doi:10.1111/j.1440-1746.2010.06323.x
16) Li, Changhong et al. “Regulation of Glucagon Secretion in Normal and Diabetic Human Islets by ?-Hydroxybutyrate and Glycine.” The Journal of Biological Chemistry 288.6 (2013): 3938–3951. PMC. Web. 6 Oct. 2017.
17) Sekhar RV, Patel SG, Guthikonda AP, Reid M, Balasubramanyam A, Taffet GE, Jahoor F. Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation. Am J Clin Nutr. 2011 Sep;94(3):847-53. doi: 10.3945/ajcn.110.003483. Epub 2011 Jul 27.
18) Kasai K, Kobayashi M, Shimoda SI. Stimulatory effect of glycine on human growth hormone secretion. Metabolism. 1978 Feb;27(2):201-8.
19) Lustgarten MS, Price LL, Phillips EM, Fielding RA. Serum glycine is associated with regional body fat and insulin resistance in functionally-limited older adults. PLoS One. 2013 Dec 31;8(12):e84034. doi: 10.1371/journal.pone.0084034. eCollection 2013.
20) Schwieler L, Linderholm KR, Nilsson-Todd LK, Erhardt S, Engberg G. Clozapine interacts with the glycine site of the NMDA receptor: electrophysiological studies of dopamine neurons in the rat ventral tegmental area. Life Sci. 2008 Aug 1;83(5-6):170-5. doi: 10.1016/j.lfs.2008.05.014. Epub 2008 Jun 10.
21) Gusev EI, Skvortsova VI, Dambinova SA, Raevskiy KS, Alekseev AA, Bashkatova VG, Kovalenko AV, Kudrin VS, Yakovleva EV. Neuroprotective effects of glycine for therapy of acute ischaemic stroke. Cerebrovasc Dis. 2000 Jan-Feb;10(1):49-60.
Note from Nelson: I take it every day (1000 mg twice per day) along with N-Acetyl-Cysteine - NAC (600 mg twice per day) to increase my glutathione.
