L-Glycine
L‑Glycine
Snapshot
L‑Glycine is the simplest amino acid, serving as a building block for proteins, a neurotransmitter in the central nervous system, and a precursor for glutathione synthesis, supporting sleep, detoxification, and connective tissue health.
What is L‑Glycine?
L‑Glycine is a nonessential amino acid that the body synthesizes endogenously. It plays roles in protein structure, neurotransmission (inhibitory signaling in the spinal cord and brainstem), and as a substrate for porphyrin and glutathione synthesis.
Where It Comes From
Dietary glycine is abundant in collagen‑rich foods—such as bone broth, skin, and connective tissues—and in protein sources like meat, fish, dairy, and legumes. Supplements provide free‑form L‑glycine powder or capsules.
Key Nutrients & Compounds
Supplemental L‑glycine delivers the pure L‑isomer. It works synergistically with other amino acids (proline, hydroxyproline) to support collagen formation and with cysteine and glutamate in the synthesis of the antioxidant glutathione.
Health Benefits
Glycine promotes restful sleep by acting on NMDA and glycine receptors. It supports detoxification by contributing to glutathione production in the liver and aids connective tissue health through collagen synthesis. Glycine also modulates inflammation and may improve metabolic health.
Recommended Dosage
Typical doses range from 3 to 5 grams before bedtime for sleep support, or 1 to 3 grams daily for metabolic and collagen benefits. Higher doses (up to 10 g) are used under clinical guidance for specific therapeutic protocols.
How to Use It
Mix L‑glycine powder into water, juice, or warm beverages and consume in the evening to promote sleep, or with meals to support collagen and detox pathways. Capsules can be taken similarly based on dosing needs.
Who Should Use It?
Ideal for individuals seeking improved sleep quality, enhanced detoxification, or support for skin, joint, and gut connective tissues. It may benefit those with sleep disturbances or increased collagen demands.
Possible Interactions or Cautions
L‑Glycine is well tolerated; mild gastrointestinal upset can occur at high doses. Individuals with severe kidney or liver impairment should consult a healthcare provider before supplementing, as glycine metabolism involves the liver and kidneys.
Final Thoughts
L‑Glycine is a versatile amino acid that supports sleep, antioxidant defenses, and structural protein formation. When used at appropriate dosages, it enhances both restorative and metabolic functions.
Scientific Studies
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Yamadera, W., et al. (2007). Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes. Sleep and Biological Rhythms, 5(2), 126–131.
https://doi.org/10.1111/j.1479-8425.2007.00276.x -
Sekhar, R. V., et al. (2011). Glutathione synthesis is diminished in patients with uncontrolled diabetes and restored by dietary supplementation with cysteine and glycine. Diabetes Care, 34(1), 162–167.
https://doi.org/10.2337/dc10-1770 -
Smith, H. J., et al. (2018). Glycine supplementation enhances collagen synthesis and skin health in middle-aged women: a randomized controlled trial. Journal of Nutrition, 148(9), 1558–1565.
https://doi.org/10.1093/jn/nxy117