Approximate dose-response bands. Individual response varies — these are starting points, not prescriptions.
Well below target. Risk of deficiency symptoms tied to sleep · collagen.
Below the recommended daily target. Long-term adequacy not assured.
Daily target met. Standard nutritional support for sleep · collagen.
Common for specific health goals. Check the evidence for your situation before sustaining this level.
Past the point where extra intake typically helps. Evidence for further benefit is thin.
You're at 0% of your glycine target. The biggest single-serving sources to top it off:
Smallest amino acid; conditionally essential — endogenous synthesis is meaningful but not always sufficient. Substrate for glutathione, creatine, heme, and collagen synthesis. Inhibitory neurotransmitter at glycine receptors and co-agonist at NMDA receptors. Popular evening supplement for sleep quality.
Activates glycine receptors (chloride channels) producing inhibitory postsynaptic potentials, similar to GABA. At NMDA receptors, glycine and D-serine occupy a co-agonist site required for glutamate to activate the channel. In the periphery, glycine lowers core body temperature via thermoregulatory vasodilation — likely the mechanism behind its sleep-onset and sleep-quality benefit.
Frank deficiency is rare but functional shortfall may occur in protein-restricted diets, severe stress, or chronic illness where glycine is consumed faster than synthesised.
Well-tolerated up to ~30 g/day in studies. No established UL. High oral doses produce only mild GI distress.
Plain L-glycine powder is cheap, dissolves easily, and tastes mildly sweet. 3 g 30–60 minutes before bed is the canonical sleep-quality dose. 10–15 g/day in divided doses for glutathione support or metabolic protocols.
Absorbed efficiently via active transport in small intestine; rapidly available. Taking with food slows absorption modestly. For sleep, the on-empty-stomach taste is mild enough that timing flexibility is high.
Glycine adequacy supports glutathione synthesis and connective tissue integrity — both relevant to aging. Recent interest in glycine-NAC combinations (GlyNAC) showing improved markers of mitochondrial function and oxidative stress in older adults; healthspan endpoints pending.
Inhibitory neurotransmitter; collagen synthesis, sleep depth, glutathione precursor. Common dose 3 g before bed.