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Glycine

Amino acidsleepModerate dose evidence

Also known as: aminoacetic acid, L-glycine

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The simplest amino acid and a major building block of collagen, glutathione, and creatine. Around 3 g taken before bed has been studied for subjective sleep quality and next-day alertness in people with restricted sleep, likely by lowering core body temperature. Its sweet taste makes it a rare gram-dose amino acid that is pleasant in powders, and it appears in sleep, collagen-support, and longevity formulas.

Research summary

Acts as an inhibitory neurotransmitter and NMDA co-agonist; promotes peripheral vasodilation that lowers core temperature at sleep onset.

SleepSkinLongevity

Dosage

Daily amounts, of compound.

Lowest studiedTypical rangeHighest studiedUpper limit
3 g3–5 g——

Sleep studies used 3 g about an hour before bed. Many powders offer 3–5 g per scoop. Far higher doses have been used in clinical research for other purposes, so the sleep dose is well within a tolerated range.

Source material: synthetic

Format suitability

  • Capsule
  • Powder
  • Tablet
  • Softgel
  • Gummy
  • Liquid

Sweet and highly soluble, so it doubles as a mild sweetener in powders. 3 g is about four size-00 capsules, so powder is preferred.

Formulation notes

Pairs with magnesium, theanine, and apigenin in sleep formulas and with NAC as a glutathione precursor pair (GlyNAC).

Sources

  1. The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers (Bannai 2012)PubMed
  2. Glycine — ExamineExamine

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