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Glycine — Frequently Asked Questions

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Frequently Asked Questions

How does glycine help sleep if it is not a sedative?

Glycine works through a unique thermoregulatory mechanism rather than sedation. It activates NMDA receptors in the brain's master clock (suprachiasmatic nucleus), which triggers vasodilation in the extremities. This shunts warm blood to the skin surface, lowering core body temperature — the same natural process that occurs during normal sleep onset. The result is faster sleep initiation and better sleep quality without the grogginess associated with sedative supplements.

Why is the glycine sleep dose 3 grams — that seems like a lot?

The 3g dose is based directly on the clinical trial evidence from Bannai et al. (2012) and Inagawa et al. (2006), both of which used 3g as the intervention dose. Lower doses have not been rigorously tested for sleep. The 3g dose is actually modest in amino acid terms — glycine is the simplest amino acid, and you consume grams of it daily from dietary protein. The dose is best taken as powder dissolved in water rather than capsules (which would require 6+ pills).

Can I take glycine with magnesium glycinate?

Yes — in fact, they are complementary. Magnesium glycinate provides both magnesium and glycine (the glycine moiety), so you get some glycine from your magnesium supplement already. Adding supplemental glycine powder on top provides the full 3g dose needed for the thermoregulatory sleep effect. The combination of magnesium (for GABA support) and glycine (for thermoregulation) addresses sleep through two distinct mechanisms.

Full Glycine Guide

References

  1. (). The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. Frontiers in Neurology. DOI
  2. (). Subjective effects of glycine ingestion before bedtime on sleep quality. Sleep and Biological Rhythms. DOI
  3. (). The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus. Neuropsychopharmacology. DOI
  4. (). Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes. Sleep and Biological Rhythms. DOI