Glycine
Sleep
Simple amino acid studied for subjective sleep quality and next-day fatigue.
What the evidence says
A small number of human trials, mostly small and Japanese-industry funded, reporting better subjective sleep. Promising, not settled.
What studies used
3 g before bed in the published trials. Before bed.
Reported from published studies and product labelling — a record of what was used in research, not a recommendation. What is right for you is a conversation with a clinician.
Evidence base
established literature
Large human evidence base: several phase 3 or 4 trial reports, plus multiple meta-analyses or systematic reviews.
This letter measures how much human research exists, not whether it works for you — the tier above (Limited) is the read on quality.
Research (12)
- New therapeutic strategy for amino acid medicine: glycine improves the quality of sleepJ Pharmacol Sci · 2012
- Dietary Protocols to Promote and Improve Restful Sleep: A Narrative ReviewNutr Rev · 2026
- Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A ReviewOxid Med Cell Longev · 2017
- Glycine and N-acetylcysteine (GlyNAC) supplementation in older adults improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, insulin resistance, endothelial dysfunction, genotoxicity, muscle strength, and cognition: Results of a pilot clinical trialClin Transl Med · 2021
- Sleep-wake physiologyHandb Clin Neurol · 2019
- The effect of glycine administration on the characteristics of physiological systems in human adults: A systematic reviewGeroscience · 2024
- Nutritional Modulation of Sleep Latency, Duration, and Efficiency: A Randomized, Repeated-Measures, Double-Blind Deception StudyMed Sci Sports Exerc · 2023
- Nutritional geometry framework of sleepLife Sci · 2023
- Neuronal network controlling REM sleepJ Sleep Res · 2025
- Glycine and N-acetylcysteine supplementation, with or without exercise, in brain health and functional aging: implications for sarcopenia and frailty in older adultsFront Nutr · 2026
- Dietary glycine supplementation enhances postweaning growth and meat quality of pigs with intrauterine growth restrictionJ Anim Sci · 2023
- Metabolic impact of dietary glycine supplementation in individuals with severe obesitySci Rep · 2025
Turn Glycine into a plan that's yours
The info above is free. Membership makes it personal, the Coach answers questions about your exact stack, the Stack tracks it for you, and the Verified Sources shows you how to vet what you buy.
- ✓ AI Coach, ask anything about your stack. It does the dosing math, flags interactions, and tells you what to do next.
- ✓ Personal Stack, save your protocol, track it across devices, log doses, get a heads-up before a vial runs out.
- ✓ Verified Sources, the vetted reference for checking quality and sourcing, members only.
Cancel anytime · or save with $59.99/yr · Coach + Stack included