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Glycine

Amino Acids

Also known as: Aminoacetic acid

Glycine is the smallest amino acid and a major inhibitory neurotransmitter. It is used for sleep quality, temperature regulation, glucose metabolism, and as the main structural amino acid in collagen.

Best Timing

Take 30–60 minutes before bed for sleep. Take with meals if using for glucose or collagen support.

Absorption

Rapidly absorbed; peaks in plasma within ~1 hour. Crosses the blood-brain barrier to act on CNS glycine and NMDA receptors.

Health Goals
🌙Sleep✨Skin😊Mood🧬Longevity
Who Should Take This
High-Stress IndividualsElderly (60+)Athletes
  • Improves subjective sleep quality and reduces sleep-onset time
  • Lowers core body temperature to promote deep sleep
  • Supports collagen synthesis (one-third of collagen is glycine)
  • Improves insulin sensitivity and fasting glucose
  • Calming effect via NMDA and glycine receptors
  • Precursor to glutathione, a master antioxidant
Sleep quality3 g

30–60 min before bed

Dose used in most clinical trials

Collagen / skin support5–10 g

Daily

Often combined with collagen peptides

Glucose / metabolic5 g

Before carb-heavy meals

Early evidence only

  • -Glycine powder – sweet-tasting, easy to mix
  • -Capsules
  • -Magnesium glycinate – paired with Mg for sleep and calming effects
Bone brothSkin-on poultry and porkGelatin and collagen-rich cutsFish skin
MagnesiumSynergy

Magnesium glycinate combines both for complementary calming and sleep effects.

MelatoninSynergy

Different mechanisms — melatonin shifts sleep onset, glycine deepens sleep. Can be stacked.

Collagen PeptidesSynergy

Glycine is a rate-limiting amino acid in collagen synthesis.

NACSynergy

Both feed glutathione production — glycine and cysteine are two of its three building blocks.

Read research on Glycine

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