Glycine

free amino acid powder

The smallest amino acid, cheap and abundant in food. Sold for sleep on a handful of small trials, and studied in combination with NAC in older adults.

last reviewed 2026-08-30

by draft — unverified

GRADE

CLAIM

SPECIES

EFFECT

STUDIES

subjective sleep quality — grade C, small effect (human-rct)

Yamadera et al. (2007)

species humandesign RCT, single-blind crossovern 11duration acute (single nights)dose 3 g before bedfunding industryoutcome polysomnography, subjective sleep quality

Faster sleep onset and better-rated sleep — in eleven people, funded by the amino-acid manufacturer. Cheap enough that nobody has run the big trial.

oxidative stress in older adults (with NAC) — grade C, unclear effect (human-rct)

Grade timeline

No grade movement since first review.

Dosing & safety

TYPICAL SUPPLEMENT DOSE3 g before bed

DOSES USED IN STUDIES3 g/day (sleep trials); 100 mg/kg/day (GlyNAC trials)

UPPER LIMITnone established

COST SNAPSHOT

No product records for this compound yet.

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