Amino Acid
Glycine
Also known as: Gly
Simplest amino acid with diverse roles in collagen synthesis, sleep quality, neurotransmission, and detoxification.
Daily target & upper limit
3 g / dayGlycine has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:
Glycine dosage reference →Primary uses
- Sleep quality
- Collagen synthesis
- Detoxification
- Neuroprotection
How it works
- Inhibitory neurotransmitter
- Precursor to glutathione
- 1/3 of collagen amino acids
- Lowers core body temperature
Dosage
- Typical range
- 3-5 g before bed for sleep; up to 10-15g for other uses
- Timing
- Before bed for sleep
- With food
- Optional
- Duration
- Safe long-term
- Special populations
- Poor sleepers, detox support
Forms
- Powder
- Capsules
Safety
Common side effects
- Mild sedation
- GI upset at high doses
Contraindications
- None
Products containing Glycine
Top-scoring supplements in our catalog that list Glycine on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
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Known interactions
Evidence notes
Growing evidence for sleep and health
Grade B: Some human trials support key claims; further confirmation needed.
Cited research for Glycine
Clinical studies referenced across Formulate guides that mention glycine. Each links to the full study page with PubMed source + the guides that cite it.
- Kawai N, Sakai N, Okuro M, et al. (2015)Neuropsychopharmacology
The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus
- Bannai and Kawai (2012)Journal of Pharmacological Sciences
New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep
- Yamadera W, Inagawa K, Chiba S, et al. (2007)Sleep and Biological Rhythms
Glycine ingestion improves subjective sleep quality in human volunteers
Glycine compared head-to-head
Related in Amino Acid
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Open the checkerMedical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider.