Glycine - NutraPedia

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Glycine: Overview of Uses and Effects

1. Conditions Studied

Glycine has been studied for a variety of conditions, including:

  • Schizophrenia
  • Stroke
  • Sleep quality improvement
  • Metabolic disorders
  • Inflammatory conditions
  • Neurological disorders

2. Efficacy in Treating Conditions

The effectiveness of glycine in treating these conditions varies:

  • In schizophrenia, some studies suggest glycine may enhance the effectiveness of other treatments when used as an adjunct therapy.
  • For stroke, there is limited evidence that suggests it might have neuroprotective effects when used promptly.
  • It has shown potential in improving sleep quality in some small studies.
  • Its role in metabolic disorders is still being explored, with some research indicating possible benefits for glucose metabolism.
However, more extensive and conclusive research is needed to establish its efficacy in these areas definitively.

3. Health Benefits

Glycine is associated with several health benefits, such as:

  • Supporting healthy sleep patterns
  • Acting as an inhibitory neurotransmitter, potentially benefiting mental health
  • Contributing to the production of glutathione, an important antioxidant
  • Playing a role in the synthesis of creatine, which can support muscle health and energy production

4. Possible Downsides

Glycine is generally considered safe when consumed in moderate amounts. However, some potential downsides include:

  • Mild gastrointestinal issues such as nausea or upset stomach
  • Potential interactions with certain medications, such as clozapine (an antipsychotic)
Individuals with kidney or liver disease should consult with a healthcare provider before supplementing with glycine.

5. Genetic Variations and Impact

Certain genetic variations may influence how an individual responds to glycine supplementation. For example:

  • Genetic mutations affecting glycine metabolism can lead to conditions like nonketotic hyperglycinemia, which requires medical management.
  • Research on other genetic variations related to glycine's effect on health is ongoing and may lead to personalized approaches to supplementation in the future.
As genetic research advances, more information may become available on the interaction between glycine supplementation and specific genetic profiles.

Impact of Glycine on Metabolism and Health

Glycine, a conditionally essential and functional amino acid for mammals, plays an integral role in various metabolic processes. Although glycine is produced from other compounds primarily in the liver and kidneys, its synthesis may not be sufficient, particularly when animals are diseased.

Glycine is pivotal in the synthesis of critical biomolecules, including glutathione, heme, creatine, nucleic acids, and uric acid. It also aids in the digestion and absorption of dietary fats through bile acids.

Health benefits of glycine encompass tissue protection, enhanced antioxidant capacity, stimulation of protein synthesis and wound healing, immunity enhancement, and treatment of conditions like obesity, diabetes, cardiovascular diseases, and inflammatory diseases.

Research on collagen, the most abundant protein in animals, reveals that glycine contributes to the triple helix structure of collagen, influencing its stability and organization in type I collagen fibrils. Advances in this area could lead to synthetic collagen-based materials for biomedical applications and nanotechnology.

For humans, the metabolic capacity for glycine biosynthesis may not fully meet the demand for collagen synthesis, leading to a potential deficit. Glycine supplementation is recommended for a healthy metabolism, especially for adequate collagen synthesis.

In diseases like osteogenesis imperfecta (OI), mutations often replace glycine in collagen, disrupting its structure and predominantly affecting bones.

Enzyme active sites rich in specific oligopeptides, mainly G-X-Y or Y-X-G, where 'G' stands for glycine, suggest its crucial role in the flexibility and function of enzymes.

The collagen superfamily, critical for tissue integrity, involves over 20 types of collagen and several associated diseases. Mouse models with engineered collagen mutations are instrumental in studying these diseases.

Glycine's role as a neurotransmitter is dual, serving both inhibitory and excitatory functions in the CNS. Recent findings in glycine transport and receptor functions may inform new therapeutic drugs for conditions like psychosis, cognitive impairments, and pain management.

The anti-inflammatory, immunomodulatory, and cytoprotective properties of glycine suggest its potential as a treatment for inflammatory diseases.

Weak links in metabolism, such as the limited conversion of serine to glycine, can affect the management of matter and energy, highlighting the importance of glycine in metabolic regulation.

Lastly, glycine's role in various biological processes, from neurotransmission to antioxidant defense, underscores its potential as a therapeutic agent and its importance in human health.


  1. Glycine metabolism in animals and humans: implications for nutrition and health
  2. Collagen structure and stability
  3. A weak link in metabolism: the metabolic capacity for glycine biosynthesis does not satisfy the need for collagen synthesis
  4. Mutations in type I collagen genes resulting in osteogenesis imperfecta in humans
  5. Glycine residues provide flexibility for enzyme active sites
  6. Collagens and collagen-related diseases
  7. Structure and function of enzymes in heme biosynthesis
  8. The metabolic burden of creatine synthesis
  9. Glutathione synthesis
  10. The biochemical basis for the conjugation of bile acids with either glycine or taurine
  11. Glycine transporters and synaptic function
  12. Glycine receptors: recent insights into their structural organization and functional diversity
  13. Glycine potentiates the NMDA response in cultured mouse brain neurons
  14. Lessons from the knocked-out glycine transporters
  15. L-Glycine: a novel antiinflammatory, immunomodulatory, and cytoprotective agent
  16. Branch-point stoichiometry can generate weak links in metabolism: the case of glycine biosynthesis
  17. Glycine turnover and decarboxylation rate quantified in healthy men and women using primed, constant infusions of [1,2-(13)C2]glycine and [(2)H3]leucine
  18. Quantitative aspects of glycine and alanine nitrogen metabolism in postabsorptive young men: effects of level of nitrogen and dispensable amino acid intake
  19. Dynamic aspects of whole body glycine metabolism: influence of protein intake in young adult and elderly males
  20. Biochemistry and evolutionary biology: two disciplines that need each other?
  21. The elephant knee joint: morphological and biomechanical considerations
  22. Degenerative arthritis in a black rhinoceros
  23. Degenerative joint disease in African great apes: an evolutionary perspective
  24. Pathology and the posture of Neanderthal man
  25. Roles of dietary glycine, proline, and hydroxyproline in collagen synthesis and animal growth
  26. Low micronutrient intake may accelerate the degenerative diseases of aging through allocation of scarce micronutrients by triage
  27. High glycine concentration increases collagen synthesis by articular chondrocytes in vitro: acute glycine deficiency could be an important cause of osteoarthritis
  28. 5-Oxoprolinuria in patients with and without defects in the gamma-glutamyl cycle
  29. Urinary excretion of 5-oxoproline (pyroglutamic aciduria) as an index of glycine insufficiency in normal man
  30. Oxoproline kinetics and oxoproline urinary excretion during glycine- or sulfur amino acid-free diets in humans
  31. Urinary excretion of 5-L-oxoproline (pyroglutamic acid) is increased during recovery from severe childhood malnutrition and responds to supplemental glycine
  32. Dietary Glycine Is Rate-Limiting for Glutathione Synthesis and May Have Broad Potential for Health Protection
  33. Long-term patterns of urinary pyroglutamic acid in healthy humans
  34. Urinary excretion of 5-L-oxoproline (pyroglutamic acid) is increased in normal adults consuming vegetarian or low protein diets
  35. Urinary excretion of 5-L-oxoproline (pyroglutamic acid) during early life in term and preterm infants
  36. Nitrogen metabolism in preterm infants fed human donor breast milk: the possible essentiality of glycine
  37. A simple practice guide for dose conversion between animals and human
  38. High dose glycine nutrition affects glial cell morphology in rat hippocampus and cerebellum
  39. Chronic high-dose glycine nutrition: effects on rat brain cell morphology
  40. Long-term results in 144 localized Ewing's sarcoma patients treated with combined therapy
  41. Double-blind, placebo-controlled, crossover trial of glycine adjuvant therapy for treatment-resistant schizophrenia
  42. Efficacy of high-dose glycine in the treatment of enduring negative symptoms of schizophrenia
  43. Adjunctive high-dose glycine in the treatment of schizophrenia
  44. High-dose glycine treatment of refractory obsessive-compulsive disorder and body dysmorphic disorder in a 5-year period
  45. Protein digestion and amino acid and peptide absorption
  47. 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
  48. Deciphering the mechanisms of intestinal imino (and amino) acid transport: the redemption of SLC36A1
  49. Intestinal transport of amino acid residues of dipeptides. I. Influx of the glycine residue of glycyl-L-proline across mucosal border
  50. Functional characterization of dipeptide transport system in human jejunum
  51. Transport of glycyl-L-proline by human intestinal brush border membrane vesicles
  52. Functional differentiation of human jejunum and ileum: a comparison of the handling of glucose, peptides, and amino acids
  53. Absorption and malabsorption of glycine and glycine peptides in man
  54. The metabolic response to ingested glycine
  55. Intestinal glucose and amino acid absorption in healthy volunteers and noninsulin-dependent diabetic subjects
  56. Increased glycine absorption rate associated with acute bacterial infections in man
  57. Effect of systemic infections on glycylglycine absorption rate from the human jejunum in vivo
  58. Impairment of glycine absorption by glucose and galactose in man
  59. Effect of intraluminal concentrations on the impairment of glycine adsorption by glucose in the human jejunum
  60. Comparison of intestinal absorption rates of glycine and glycylglycine in man and the effect of glucose in the perfusing fluid
  61. A kinetic study of the interactions between amino acids and monosaccharides at the intestinal brush-border membrane
  62. Some factors influencing absorption rates of the digestion products of protein and carbohydrate from the proximal jejunum of man and their possible nutritional implications
  63. Glycine nitrogen metabolism in man
  64. Glycine cleavage system: reaction mechanism, physiological significance, and hyperglycinemia
  65. Genetic heterogeneity of the GLDC gene in 28 unrelated patients with glycine encephalopathy
  66. Regulation of hepatic glycine catabolism by glucagon
  67. Increased activity of renal glycine-cleavage-enzyme complex in metabolic acidosis
  68. Glycine transporters: crucial roles of pharmacological interest revealed by gene deletion
  69. Glycine transporters: essential regulators of synaptic transmission
  70. Glycine transporter inhibitor attenuates the psychotomimetic effects of ketamine in healthy males: preliminary evidence
  71. Glial transport of the neuromodulator D-serine
  72. Uptake of D- and L-serine in C6 glioma cells
  73. Cotransmission of GABA and glycine to brain stem motoneurons
  74. Developmental dissociation of presynaptic inhibitory neurotransmitter and postsynaptic receptor clustering in the hypoglossal nucleus
  75. Distinctive glycinergic currents with fast and slow kinetics in thalamus
  76. IPSC kinetics at identified GABAergic and mixed GABAergic and glycinergic synapses onto cerebellar Golgi cells
  77. Vesicular storage of glycine in glutamatergic terminals in mouse hippocampus
  78. Glycinergic nerve endings in hippocampus and spinal cord release glycine by different mechanisms in response to identical depolarizing stimuli
  79. Strychnine binding associated with glycine receptors of the central nervous system
  80. Modulation of glycine receptor function: a novel approach for therapeutic intervention at inhibitory synapses?
  81. Developmental and regional expression in the rat brain and functional properties of four NMDA receptors
  82. Multiple structural elements determine subunit specificity of Mg2+ block in NMDA receptor channels
  83. Glutamate receptor ion channels: structure, regulation, and function
  84. Zinc potentiates agonist-induced currents at certain splice variants of the NMDA receptor
  85. Glycine is a coagonist at the NMDA receptor/channel complex
  86. The glycine coagonist site of the NMDA receptor
  87. Glycine uptake governs glycine site occupancy at NMDA receptors of excitatory synapses
  88. Are glycine sites saturated in vivo?
  89. Strychnine-sensitive glycine receptors depress hyperexcitability in rat dentate gyrus
  90. Glycine-gated chloride channels depress synaptic transmission in rat hippocampus
  91. Morphologically identified glycinergic synapses in the hippocampus
  92. Cellular and subcellular localization of the inhibitory glycine receptor in hippocampal neurons
  93. Sodium-dependent release of exogenous glycine from preloaded rat hippocampal synaptosomes
  94. Morphological and electrical characteristics of postnatal hippocampal neurons in culture: the presence of bicuculline- and strychnine-sensitive IPSPs
  95. Glycine intracerebroventricular administration disrupts mitochondrial energy homeostasis in cerebral cortex and striatum of young rats
  96. Neurochemical evidence that glycine induces bioenergetical dysfunction
  97. In vitro evidence that D-serine disturbs the citric acid cycle through inhibition of citrate synthase activity in rat cerebral cortex
  98. Creatine administration prevents Na+,K+-ATPase inhibition induced by intracerebroventricular administration of isovaleric acid in cerebral cortex of young rats
  99. High-dose glycine added to olanzapine and risperidone for the treatment of schizophrenia
  100. The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers
  101. Glycine attenuates myocardial ischemia-reperfusion injury by inhibiting myocardial apoptosis in rats
  102. Glycine reduces platelet aggregation
  103. Plasma Glycine and Risk of Acute Myocardial Infarction in Patients With Suspected Stable Angina Pectoris
  104. Tissue distribution of glycine N-methyltransferase, a major folate-binding protein of liver
  105. Deficiency of glycine N-methyltransferase aggravates atherosclerosis in apolipoprotein E-null mice
  106. alpha-hydroxybutyrate is an early biomarker of insulin resistance and glucose intolerance in a nondiabetic population
  107. BMI, RQ, diabetes, and sex affect the relationships between amino acids and clamp measures of insulin action in humans
  108. Metabolite profiling identifies pathways associated with metabolic risk in humans
  109. Serum glycine is associated with regional body fat and insulin resistance in functionally-limited older adults
  110. Elevated serum levels of cysteine and tyrosine: early biomarkers in asymptomatic adults at increased risk of developing metabolic syndrome
  111. Identification of serum metabolites associated with risk of type 2 diabetes using a targeted metabolomic approach
  112. Relationship between insulin resistance and amino acids in women and men
  113. Genetic variants associated with glycine metabolism and their role in insulin sensitivity and type 2 diabetes
  114. Dimethylglycine Deficiency and the Development of Diabetes
  115. Effect of insulin sensitizer therapy on amino acids and their metabolites
  116. A novel test for IGT utilizing metabolite markers of glucose tolerance
  117. Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation
  118. Interaction of ingested leucine with glycine on insulin and glucose concentrations
  119. The neurotransmitters glycine and GABA stimulate glucagon-like peptide-1 release from the GLUTag cell line
  120. Effect of glycine on insulin secretion and action in healthy first-degree relatives of type 2 diabetes mellitus patients
  121. Glycine therapy inhibits the progression of cataract in streptozotocin-induced diabetic rats
  122. Free lysine, glycine, alanine, glutamic acid and aspartic acid reduce the glycation of human lens proteins by galactose
  123. Decrease in glycation of lens proteins by lysine and glycine by scavenging of glucose and possible mitigation of cataractogenesis
  124. Metabolomics study of type 2 diabetes using ultra-performance LC-ESI/quadrupole-TOF high-definition MS coupled with pattern recognition methods
  125. Plasma Amino Acids vs Conventional Predictors of Insulin Resistance Measured by the Hyperinsulinemic Clamp
  126. Novel biomarkers for pre-diabetes identified by metabolomics
  127. Glutathione synthesis is diminished in patients with uncontrolled diabetes and restored by dietary supplementation with cysteine and glycine
  128. Glycine treatment decreases proinflammatory cytokines and increases interferon-gamma in patients with type 2 diabetes
  129. Stimulatory effect of glycine on human growth hormone secretion
  130. Alpha-cells of the endocrine pancreas: 35 years of research but the enigma remains
  131. Regulation of glucagon secretion in normal and diabetic human islets by γ-hydroxybutyrate and glycine
  132. Absorption of zinc by the rat ileum: effects of histidine and other low-molecular-weight ligands
  133. Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection
  134. The number of glycine residues which limits intact absorption of glycine oligopeptides in human jejunum
  135. Synthesis, molecular structure and vibrational spectra of a dimeric complex formed by cobalt and glycine

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