Glycine
Simple amino acid supporting sleep quality and collagen synthesis.
By Suplagen Team · Updated
What it is
Glycine is the simplest amino acid, serving as a neurotransmitter, collagen building block, and glutathione precursor.
How it works
Inhibitory neurotransmitter (glycine receptors); lowers core body temperature to promote sleep onset; key for collagen triple helix.
What the evidence says
Moderate evidence for improving subjective sleep quality; well-tolerated even at high doses.
How much to take
The catalog range is 3 to 5 g daily, with 5 g as the ceiling. That's a powder-sized dose; capsules would mean swallowing a handful, which is why powder is the practical form.
3 g is the amount the sleep quality trials used, and it's where to start. Glycine is well tolerated even at the top of the range, and its mildly sweet taste mixes easily into water.
When and how to take it
About 1 hour before bed for sleep. Glycine works partly by lowering core body temperature, which is part of how the body prepares for sleep, so the timing does real work.
It pairs with everything else in our sleep guide without conflicts, and it carries an emerging grade for skin thanks to its role in collagen.
Who should skip it
Glycine is safe in pregnancy and has no contraindicated conditions. The single interaction is with clozapine, at a moderate level, so anyone on it needs a doctor's approval. Otherwise it's one of the cleanest supplements in the catalog.
Safety Notes
- Very safe; sweet taste. Powder form preferred at 3g doses (would require many capsules).
- clozapine: May reduce clozapine effectiveness; consult physician.
Common questions
What is the right glycine dosage for sleep?
3 g about an hour before bed. That's the dose behind its moderate evidence for sleep quality. The range runs to 5 g, but more isn't better for sleep.
How much glycine can you take per day?
Up to 5 g daily per the catalog ceiling. It's well tolerated across the range, and there are no listed contraindications.
When is the best time to take glycine?
One hour before bed if sleep is the goal. For skin, timing doesn't matter, but the evening slot still works fine.