Glycine: The Small Amino Acid with Big Health Benefits

Written By Ingrid Huddleston

You may have heard whispers about glycine in health and wellness circles, and for good reason. This small but mighty amino acid is gaining attention as a key player in everything from better sleep to healthier skin. While our bodies can produce glycine, research suggests we often need more than we can make, making it a "conditionally essential" nutrient for optimal health.

How Does Glycine Work?

Glycine is a versatile workhorse in the body. Its benefits can be traced back to three main jobs:

  1. A Master Building Block: Glycine is the most abundant amino acid in collagen, the protein that provides structure and strength to our skin, bones, and connective tissues.

  2. A Powerful Precursor: It helps the body produce two vital compounds: glutathione, the body's "master antioxidant" that protects cells from damage, and creatine, which provides energy to muscles.

  3. A Calming Neurotransmitter: In the brain and spinal cord, glycine acts as a signal that helps calm the nervous system, which is key for relaxation and sleep.

Key Benefits Backed by Science

While glycine has many roles, human clinical research highlights a few standout benefits:

  • Deeper, More Restful Sleep: This is one of the most well-supported uses for glycine. Studies consistently show that taking 3 grams of glycine before bed can help people fall asleep faster, improve sleep quality, and feel less fatigued the next day, all without causing grogginess.

  • Healthier Joints and Skin: Because glycine is essential for creating collagen, it plays a direct role in the health of our connective tissues. Clinical trials on supplements rich in glycine and other amino acids have found they can significantly reduce joint pain and stiffness in adults with knee discomfort. Similar studies on glycine-containing collagen supplements have demonstrated improvements in skin hydration, elasticity, and the appearance of wrinkles.

  • Metabolic and Antioxidant Support: Low levels of glycine are consistently linked to metabolic health issues. By helping to create the powerful antioxidant glutathione, glycine supplementation may help reduce the oxidative stress associated with these conditions and support overall metabolic wellness.

Who Might Benefit from Glycine?

Based on the research, glycine could be a helpful supplement for:

  • Individuals who have trouble falling asleep or experience poor sleep quality.

  • People looking to support the health and integrity of their skin and joints.

  • Anyone interested in boosting their body's natural antioxidant defenses and promoting healthy aging.

Safety and Considerations

Glycine is generally considered safe and is well-tolerated by most people. Some individuals may experience mild stomach upset, which can often be avoided by starting with a lower dose.

It is very important to note that glycine should not be taken with the antipsychotic medication clozapine, as it can interfere with its effectiveness. As with any supplement, it is always best to consult with your healthcare provider before adding glycine to your routine.

The Takeaway

Glycine is more than just a simple amino acid; it's a foundational nutrient that supports our body's structure, energy systems, and nervous system. From promoting a restorative night's sleep to helping maintain healthy skin and joints, its benefits are both broad and backed by a growing body of science. As part of a balanced health plan, glycine offers a simple yet powerful way to support your overall well-being.

  • Glycine is a conditionally essential amino acid that plays several vital roles in the body. It helps build collagen, supports antioxidant production, boosts muscle energy, and acts as a calming neurotransmitter in the brain, aiding sleep and nervous system regulation.

  • Glycine has a calming effect on the nervous system. Clinical studies show that taking 3 grams before bed can help people fall asleep faster, improve sleep quality, and feel more refreshed the next day—without the grogginess common with sleep aids.

  • Research suggests glycine may support:

    • Restful sleep: Promotes faster sleep onset and improved sleep quality

    • Skin and joint health: Supports collagen production for stronger connective tissues

    • Antioxidant protection: Aids in creating glutathione, the body’s master antioxidant

    Metabolic wellness: Low glycine levels are linked to metabolic imbalances

  • Glycine may benefit:

    • People who struggle with sleep quality or fatigue

    • Individuals looking to maintain healthy skin, joints, and connective tissue

    • Anyone interested in antioxidant support and healthy aging

    • Those experiencing oxidative stress or poor metabolic markers

  • Yes, glycine is generally well-tolerated and considered safe for most people. Mild stomach upset can occur at high doses but is uncommon. However, it should not be used by individuals taking the antipsychotic medication clozapine, due to potential interactions.

  • Yes. Glycine is a major component of collagen, which supports the strength and elasticity of skin, joints, and connective tissue. Clinical trials have shown glycine-containing supplements can improve joint comfort and reduce visible signs of skin aging.

  • Unlike many amino acids primarily used for building proteins, glycine plays multiple roles: structural (in collagen), antioxidant (in glutathione), energy (in creatine), and neurological (as a calming neurotransmitter).

Works Cited

  1. Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/28337245/

  2. What is the mechanism of Glycine? - Patsnap Synapse, accessed June 27, 2025, https://synapse.patsnap.com/article/what-is-the-mechanism-of-glycine

  3. Glycine: The Smallest Anti-Inflammatory Micronutrient - PMC - PubMed Central, accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC10379184/

  4. Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review - PMC, accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC5350494/

  5. High glycine concentration increases collagen synthesis by articular ..., accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC6153947/

  6. Top 9 Benefits and Uses of Glycine - Healthline, accessed June 27, 2025, https://www.healthline.com/nutrition/glycine

  7. What is Glycine? - News-Medical.net, accessed June 27, 2025, https://www.news-medical.net/health/What-is-Glycine.aspx

  8. Learn the benefits of Glycine for Anti-Aging and Longevity - Decode Age, accessed June 27, 2025, https://decodeage.com/blogs/supplements/benefits-of-glycine-in-anti-aging-and-longevity

  9. Collagen Supplementation for Joint Health: The Link between Composition and Scientific Knowledge - PMC - PubMed Central, accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC10058045/

  10. High glycine concentration increases collagen synthesis by articular chondrocytes in vitro: acute glycine deficiency could be an important cause of osteoarthritis - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/30006659/

  11. Control analysis of collagen synthesis by glycine, proline and lysine in bovine chondrocytes in vitro - Its relevance for medicine and nutrition - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/37598999/

  12. (PDF) High glycine concentration increase collagen synthesis by articular chondrocytes in vitro - Acute glycine deficiency could be an important cause of osteoarthritis - ResearchGate, accessed June 27, 2025, https://www.researchgate.net/publication/326032978_High_glycine_concentration_increase_collagen_synthesis_by_articular_chondrocytes_in_vitro_-_Acute_glycine_deficiency_could_be_an_important_cause_of_osteoarthritis

  13. Glutathione metabolism and its implications for health - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/14988435/

  14. Dietary Glycine Is Rate-Limiting for Glutathione Synthesis and May Have Broad Potential for Health Protection - PubMed Central, accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC5855430/

  15. Glycine - Rupa Health, accessed June 27, 2025, https://www.rupahealth.com/biomarkers/glycine

  16. Dietary Glycine Is Rate-Limiting for Glutathione Synthesis and May Have Broad Potential for Health Protection - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/29559876/

  17. Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/21795440/

  18. Dietary exposure to creatine-precursor amino acids in the general population - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/40413365/

  19. The metabolic burden of creatine synthesis - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/21387089/

  20. Creatine biosynthesis and transport in health and disease - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/26542286/

  21. Dietary glycine supplementation enhances creatine availability in tissues of pigs with intrauterine growth restriction - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/39513322/

  22. www.acnp.org, accessed June 27, 2025, https://www.acnp.org/g4/GN401000008/Default.htm#:~:text=Glycine%20is%20the%20major%20inhibitory,NMDA)%20subtype%20of%20glutamate%20receptor.

  23. Neurotransmitters: What They Are, Functions & Types, accessed June 27, 2025, https://my.clevelandclinic.org/health/articles/22513-neurotransmitters

  24. Glycine neurotransmitter transporters: an update - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/11396606/

  25. Glycine Neurotransmitter | PPT - SlideShare, accessed June 27, 2025, https://www.slideshare.net/slideshow/glycine-25f9/263760430

  26. Glycine: Uses, Interactions, Mechanism of Action | DrugBank Online, accessed June 27, 2025, https://go.drugbank.com/drugs/DB00145

  27. Interactions Involving Glycine and Other Amino Acid Neurotransmitters: Focus on Transporter-Mediated Regulation of Release and Glycine–Glutamate Crosstalk - PubMed Central, accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC11275102/

  28. What is Glycine used for? - Patsnap Synapse, accessed June 27, 2025, https://synapse.patsnap.com/article/what-is-glycine-used-for

  29. Beneficial effects of glycine (bioglycin) on memory and attention in ..., accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/10587285/

  30. The glycine site of NMDA receptors: A target for cognitive enhancement in psychiatric disorders - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/30738126/

  31. Subjective effects of glycine ingestion before bedtime on sleep quality - ResearchGate, accessed June 27, 2025, https://www.researchgate.net/publication/230085537_Subjective_effects_of_glycine_ingestion_before_bedtime_on_sleep_quality

  32. The Effects of Glycine on Subjective Daytime Performance in ..., accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC3328957/

  33. Does Glycine Help You Sleep - Consensus Academic Search Engine, accessed June 27, 2025, https://consensus.app/questions/does-glycine-help-sleep/

  34. Glycine – A Small Molecule with a Big Impact on Sleep - ZRT Laboratory, accessed June 27, 2025, https://www.zrtlab.com/blog/archive/glycine-big-impact-sleep/

  35. New therapeutic strategy for amino acid medicine: glycine improves ..., accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/22293292/

  36. The Sleep-Promoting and Hypothermic Effects of Glycine are Mediated by NMDA Receptors in the Suprachiasmatic Nucleus - PubMed Central, accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4397399/

  37. Effects of glycine on metabolic syndrome components: a review, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/35013990/

  38. Glycine Metabolism and Its Alterations in Obesity and Metabolic Diseases - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/31208147/

  39. Alterations in glycine metabolism in obesity and chronic metabolic diseases - an update on new advances - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/36542534/

  40. Glycine Increases Insulin Sensitivity and Glutathione Biosynthesis and Protects against Oxidative Stress in a Model of Sucrose-Induced Insulin Resistance - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/29675131/

  41. Glycine Increases Insulin Sensitivity and Glutathione Biosynthesis and Protects against Oxidative Stress in a Model of Sucrose-Induced Insulin Resistance - PubMed Central, accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC5841105/

  42. Effect of glycine on insulin secretion and action in healthy first ..., accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/11456285/

  43. Study Details | The Effects of Glycine on Atherosclerosis and Metabolic Syndrome-related Parameters. | ClinicalTrials.gov, accessed June 27, 2025, https://www.clinicaltrials.gov/study/NCT03850314?term=GLYCINE&viewType=Table&rank=10

  44. Obesity-Related Glycine Deficiency: Investigating a Long-standing Metabolic Paradox Using Bedside and Bench Approaches | ClinicalTrials.gov, accessed June 27, 2025, https://clinicaltrials.gov/ct2/show/NCT04660513?lupd_s=11%2F29%2F2020

  45. Glycine as a therapeutic supplement | EBSCO Research Starters, accessed June 27, 2025, https://www.ebsco.com/research-starters/health-and-medicine/glycine-therapeutic-supplement

  46. GLYCINE: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews, accessed June 27, 2025, https://www.webmd.com/vitamins/ai/ingredientmono-1072/glycine

  47. [Could we use a serum level of glycine as a prognostic factor of its efficacy in schizophrenic patients?] - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/20672518/

  48. Glycine: Health Benefits, Side Effects, Uses, Dose & Precautions - RxList, accessed June 27, 2025, https://www.rxlist.com/supplements/glycine.htm

  49. The cognitive effects of modulating the glycine site of the NMDA receptor with high-dose glycine in healthy controls - ResearchGate, accessed June 27, 2025, https://www.researchgate.net/publication/5874608_The_cognitive_effects_of_modulating_the_glycine_site_of_the_NMDA_receptor_with_high-dose_glycine_in_healthy_controls

  50. The cognitive effects of modulating the glycine site of the NMDA receptor with high-dose glycine in healthy controls - PubMed, accessed June 27, 2025, https://pubmed.ncbi.nlm.nih.gov/17972276/

  51. Are Collagen Supplements Helpful for Arthritis?, accessed June 27, 2025, https://www.arthritis.org/health-wellness/treatment/complementary-therapies/supplements-and-vitamins/can-collagen-supplements-help-arthritis

  52. Effects of Non-Essential Amino Acids on Knee Joint Conditions in ..., accessed June 27, 2025, https://www.mdpi.com/2072-6643/14/17/3628

  53. A Clinical Trial Shows Improvement in Skin Collagen, Hydration, Elasticity, Wrinkles, Scalp, and Hair Condition following 12-Week Oral Intake of a Supplement Containing Hydrolysed Collagen - ResearchGate, accessed June 27, 2025, https://www.researchgate.net/publication/382169793_A_Clinical_Trial_Shows_Improvement_in_Skin_Collagen_Hydration_Elasticity_Wrinkles_Scalp_and_Hair_Condition_following_12-Week_Oral_Intake_of_a_Supplement_Containing_Hydrolysed_Collagen

  54. A Clinical Trial Shows Improvement in Skin Collagen, Hydration ..., accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC11254459/

  55. Amino Acids Oral Treatment for the Amelioration of Skin, Hair, and ..., accessed June 27, 2025, https://www.foodandnutritionjournal.org/volume12number1/amino-acids-oral-treatment-for-the-amelioration-of-skin-hair-and-nails-conditions-an-open-label-study/

  56. The effect of glycine administration on the characteristics of ..., accessed June 27, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC10828290/

  57. An Update of the Promise of Glycine Supplementation for Enhancing Physical Performance and Recovery - MDPI, accessed June 27, 2025, https://www.mdpi.com/2075-4663/12/10/265

  58. Glycine Dosage: Optimal Amounts for Various Health Benefits - BRC Recovery, accessed June 27, 2025, https://brcrecovery.com/blogs/glycine-dosage/

  59. Glycine - Health Library, accessed June 27, 2025, https://myhealth.ucsd.edu/Search/19,Glycine

  60. Acute Glycine Pharmacodynamic Study - ClinicalTrials.gov, accessed June 27, 2025, https://www.clinicaltrials.gov/study/NCT01610011?term=AREA%5BBasicSearch%5D(AREA%5BBasicSearch%5D(GLYCINE))&rank=3

  61. go.drugbank.com, accessed June 27, 2025, https://go.drugbank.com/drugs/DB00145#:~:text=Deslanoside-,The%20risk%20or%20severity%20of%20adverse%20effects%20can%20be,Glycine%20is%20combined%20with%20Deslanoside.&text=Digitoxin-,The%20risk%20or%20severity%20of%20adverse%20effects%20can%20be,Glycine%20is%20combined%20with%20Digitoxin.&text=Digoxin-,The%20risk%20or%20severity%20of%20adverse%20effects%20can%20be,Glycine%20is%20combined%20with%20Digoxin.

Content Disclaimer

This information was generated and formatted using AI technology to summarize and present current scientific research on the specified supplement. While every effort has been made to ensure accuracy, clarity, and relevance, the information provided should not be considered a substitute for professional medical advice. All health claims are supported by citations from peer-reviewed studies and credible sources, which have been included for transparency and verification. Always consult a qualified healthcare provider before making decisions related to supplement use or health interventions.

Ingrid Huddleston
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