Amino Acid
Glycine
An amino acid that supports sleep quality, relaxation, and cognitive recovery.
KÖGN Health grades Glycine as B (Moderate evidence) and rates it 3.8 out of 5.
Last reviewed · June 2026
Primary effects
- Improved sleep
- Relaxation
- Cognitive recovery
How it works
Acts as an inhibitory neurotransmitter, promoting relaxation and improved sleep.
Overview
Glycine plays a role in regulating the nervous system and improving sleep quality, which directly impacts cognitive performance. It is often used before bed to enhance recovery and next-day mental clarity. While it does not provide direct cognitive stimulation, its role in recovery makes it valuable for sustained performance.
The evidence
Glycine is a simple amino acid with a dual role as both a calming and an NMDA-receptor-modulating neurotransmitter. Its clearest evidence is for sleep: small randomised trials show that 3 g before bed improves subjective sleep quality and next-day alertness, partly by lowering core body temperature. Direct waking-cognition effects are modest and mixed.
How to dose it
Sleep studies use 3 g taken about an hour before bed. It is mildly sweet and dissolves easily in water.
When to take it
Acute — taken before sleep.
Safety & side effects
Very well tolerated; occasional mild GI upset or drowsiness.
Who should avoid it
Few issues for healthy adults. Use care alongside clozapine (glycine may reduce its effect) and discuss higher doses with a clinician if you are pregnant or have kidney or liver disease.
References
Related ingredients
Graded entries that target the same cognitive goals.
Categories
Draft — the dose, safety and evidence notes on this entry were prepared from the published literature and are pending editorial and clinical review.
Educational information, not medical advice. The evidence grade is KÖGN’s editorial assessment of published research, not a health claim. Speak to a qualified clinician before changing what you take.