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Glycine
Lowers core body temperature to deepen sleep — 3g before bed reduces daytime fatigue and boosts next-day cognition.
What the evidence says
Glycine appears to help in 6 of 6 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2005–2026 with a typical study size of 20 participants.
Based on 26 studies · 5 meta-analyses · 15 RCTs · 1,601 total participants
Confidence
HighWhat the studies found
By outcome
See full supplement plans that include Glycine.
Glycine has an evidence score of 8.5/10 — very strong evidence based on 26 indexed studies, including 11 meta-analyses. Lowers core body temperature to deepen sleep — 3g before bed reduces daytime fatigue and boosts next-day cognition.
The commonly studied dose of Glycine is 3g before bed. Research points to an estimated optimal dose around 3g, with a minimum effective dose near 2g. Individual response varies — start low and adjust.
The best time to take Glycine is before bed. It can be taken on an empty stomach. Glycine acts as an inhibitory neurotransmitter and NMDA receptor co-agonist.
Last reviewed May 2026 · evidence from 39 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Glycine is a non-essential amino acid that plays a crucial role in sleep quality. Taking 3g before bed has been shown in multiple studies to improve deep sleep, reduce daytime fatigue, and enhance cognitive performance the next day. It works by lowering core body temperature, a key trigger for sleep onset.
Drops body temperature to trigger deeper sleep
Acts as a co-agonist at NMDA receptors
Key building block for collagen production
How Glycine works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
3g before bed
Can be taken without food
| Form | Type |
|---|---|
| 🧪Powder (dissolves easily, tastes sweet) | Recommended |
| 💊Capsules (need multiple for 3g dose) | Alternative |
Powder is most practical as capsules require 4-6 pills for 3g. Tastes naturally sweet, can be mixed in water or taken directly.
Minimum: 1 weeks
Optimal: 2 weeks
Cycling: Not required
Note: Take on empty stomach or with light snack before bed. 3g is the well-studied dose; higher doses are not more effective.
You can get glycine from these foods and drinks. Doses are typical per-serving estimates — actual content varies by brand, brew, cooking, etc.
2700 mg per cup
1 cup long-simmered (8+ hr). Store-bought "bone broth" varies wildly; some are barely better than stock.
Based on systematic review showing nervous system benefits. Limited specific RCT data for sleep outcomes. Effects may vary significantly between individuals.
More time in restorative deep sleep stages
Feel more refreshed and alert the next day
Fall asleep more easily
Powder has a naturally sweet taste
Glycine is a normal dietary amino acid; supplementation not well-studied in pregnancy
May be particularly beneficial for age-related sleep issues
May reduce clozapine effectiveness
May have additive effects
Tip: Take with small snack
Tip: Usually not problematic; may reduce over time
Magnesium for relaxation, glycine for deep sleep
Comprehensive sleep quality improvement
Both promote relaxation through different mechanisms
Enhanced pre-sleep relaxation and sleep quality
Apigenin for onset, glycine for deep sleep
Comprehensive sleep support
L-serine converts to glycine
Enhanced neurotransmitter and collagen support
Both support sleep through different mechanisms
Comprehensive sleep quality improvement
Glycine is generally well-tolerated and considered safe for most healthy adults at recommended doses. The most commonly reported side effects are GI discomfort, vivid dreams. Use caution if any of these apply to you: Clozapine users (glycine may affect drug efficacy).
Taurine
Likely helpsConcentrated in heart, brain, and muscle — emerging longevity data alongside proven benefits for sleep, cardiovascular function, and recovery.
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