Skip to main content

Amino Acid

L-Glycine

Also known as: Glycine, L-α-Aminoacetic acid, Aminoacetic acid

B
Evidence

A simple, non-essential amino acid with documented sleep-promoting properties through thermoregulation and GABA receptor modulation. Evidence supports its use for improving sleep latency and quality.

Primary uses

  • Sleep onset improvement
  • Sleep quality
  • Relaxation
  • Collagen synthesis

How it works

  • Glycine receptor agonist (inhibitory neurotransmitter)
  • Promotes vasodilation and heat dissipation (core temperature reduction)
  • Indirect GABA potentiation
  • CNS relaxation

Dosage

Typical range
3-10 g daily (most studies use 3g)
Timing
30-60 minutes before bed
With food
Can take with or without food
Duration
Safe for long-term daily use; benefits may increase with consistent use over 2+ weeks
Special populations
Generally well-tolerated across populations

Forms

  • L-Glycine powder or capsules· 70/100

Safety

Common side effects

  • Well-tolerated; minimal side effects at 3-10g doses
  • Mild GI effects possible at very high doses

Contraindications

  • None established at typical doses

Known interactions

Evidence notes

Good RCT evidence (Japanese trials) showing 3g glycine reduces sleep latency and improves subjective sleep quality; mechanism well-characterized.

Grade B: Some human trials support key claims; further confirmation needed.

Related in Amino Acid

Check a full stack

Formulate's free interaction checker lets you paste in any combination of supplements and medications at once — every pairing flags severity, timing, and cited evidence.

Open the checker

Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider.