Glycine for Sleep Quality
3g glycine before bed lowers core temperature and enhances deep sleep. Studies show improved next-day performance even with restricted sleep.
Dosage & Timing
Evidence Strength
4/5 — StrongGood clinical evidence from multiple human trials. Mechanism (core temp reduction via peripheral vasodilation) is well-understood.
Overview
Take 3g of glycine 30-60 minutes before bed. Glycine is an inhibitory amino acid that lowers core body temperature and improves subjective sleep quality, reducing next-day fatigue even after short sleep.
How To Do It
Get glycine powder or capsules
Glycine is inexpensive and widely available. Powder dissolves in water and tastes slightly sweet.
Take 3g before bed
Dissolve 3g in water or take capsules 30-60 minutes before bed.
Track morning response
Note sleep quality, next-day fatigue, and any digestive discomfort for 1-2 weeks before deciding whether it helps.
The Evidence
Each claim is linked to its source study. Confidence reflects the study design — systematic reviews and RCTs rank highest.
The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers↗
Bedtime glycine improved next-day subjective fatigue after restricted sleep.
Primary Literature
Who Popularized This
Interactions & Warnings
Contraindications
- ⚠Clozapine users (glycine may interact)
Interactions
- •May enhance effects of magnesium for sleep
- •Synergistic with sleep temperature optimization
Measurable Outcomes
Related Protocols
Sleep Temperature Optimization
Keep your bedroom at 65-68°F and take a warm shower 1-2 hours before bed. Core temperature drop is a key trigger for sleep onset and deep sleep.
Magnesium Threonate for Sleep
Take 200mg elemental magnesium as L-threonate before bed. This form uniquely crosses the blood-brain barrier, supporting GABA activity and sleep depth.
Caffeine Curfew
No caffeine after ~2pm (for 10pm bedtime). Caffeine's 5-6 hour half-life means afternoon intake significantly reduces deep sleep even if you fall asleep fine.
Morning Sunlight Exposure
View bright light within 60 minutes of waking to set your circadian clock. This triggers a cortisol pulse and starts a timer for melatonin release 14-16 hours later.