Supplement
Glycine
Before bed. Modest sleep benefit, low downside.
What it does
A small but real effect on sleep onset and subjective sleep quality, via mild core-temperature reduction. A nudge toward better sleep onset, not a sedative. Cheap and well-tolerated.
Acts as an inhibitory neurotransmitter and lowers core body temperature through peripheral vasodilation — both support sleep onset.
What the evidence shows
Overall evidence strength: Low certainty
Who it's for, who should skip
A low-downside nudge toward better sleep onset. The metabolic and longevity claims are animal-stage, not established in humans.
Running it
- Form
- oral
- Dose
- daily · 30 min pre-bed
Stacking & alternatives
Access & cost
Available over the counter.
Last reviewed 27 August 2026.