Glycine
The smallest amino acid and an inhibitory neurotransmitter that improves sleep quality by lowering core body temperature through peripheral vasodilation. Beyond sleep, glycine is a rate-limiting substrate for glutathione synthesis and — paired with N-acetylcysteine — has reversed multiple hallmarks of aging in human trials (the GlyNAC research).
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BiohackingHub Research TeamEditorial Research Team · Last updated: May 8, 2026
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Stacking Interactions
How Glycine interacts with other compounds
Glycine lowers core temperature for sleep onset while apigenin acts on GABA-A — two distinct sleep-onset mechanisms that combine well.
L-theanine reduces sleep-onset anxiety and glutamatergic excitation; glycine handles thermoregulatory sleep onset — non-overlapping and complementary.
Magnesium supports GABAergic tone and NMDA regulation; with glycine it rounds out a deep-sleep architecture stack.
Glycine supports glutathione and methylation balance; pairs with NAD+ precursors in longevity-oriented stacks.
Safety Profile — Tier A
Well-tolerated — strong human evidence
Contraindications
- ●Clozapine therapy — glycine may reduce clozapine efficacy
- ●Rare inborn errors of glycine metabolism
Side Effects
- ●Very well-tolerated; doses of 3-90g/day used in trials
- ●Mild GI upset or loose stool at high single doses (uncommon)
- ●Slight drowsiness when taken before bed (intended effect)