Best Glycine for Sleep
Top 1 products ranked
Last reviewed May 2026
Clinical dose: 3–5 g
Why Glycine for Sleep
Glycine plays a supporting role in sleep. Glycine is a non-essential amino acid. Supplemental glycine (often ~3 g taken before bed) has been studied for sleep quality and next-day fatigue in small trials. In clinical studies, glycine may support sleep quality when taken before bed.
What dose to look for
Clinical studies typically use 3–5 g of glycine. Common supplemental range; 3 g before bedtime has been used in small human sleep studies. Products below this range may not deliver meaningful results.
What the research says
Glycine has moderate clinical evidence for sleep benefits. A few small trials on sleep quality at 3g before bed; well-tolerated but limited study sizes Learn more
Clinical research on Glycine
MODERATE — Small but well-designed studies with PSG data · 3,000 mg (3g) before bedtime
- •Three key Japanese studies (Inagawa 2006, Yamadera 2007, Bannai 2012) consistently show 3g glycine before bedtime improves subjective sleep quality and reduces sleep onset latency. PubMed
- •2007 PSG study found glycine improved sleep efficiency and shortened latency to slow-wave sleep WITHOUT changing sleep architecture — optimizes natural sleep. PubMed
- •Mechanism: activates NMDA receptors in the suprachiasmatic nucleus, lowering core body temperature via peripheral vasodilation — the physiological trigger for sleep onset.
- •Limitation: all key studies from a single research group (Ajinomoto, a glycine manufacturer). Promising but needs independent replication.
