Glycine is a simple amino acid your body also makes. It is sold mainly for sleep, as a cheap powder with a sweet taste.
Calculator Official intake Study doses Best form Safety Sources
Glycine is not an essential nutrient, so there is no official daily intake. Only study doses are shown.
These are doses tested in research, not personal advice. Some exceed the upper limit because they were short courses or given under medical care.
3 g a day
Small Japanese trials gave 3 g glycine before bed. People reported better sleep, and sleep recordings changed in one study. After nights of shortened sleep, glycine reduced daytime sleepiness and fatigue. Studies were small and short.
Practical pick
Glycine powder or capsules (g)
Why: Plain glycine powder is cheap and dissolves in water; 3 g is about a level teaspoon.
Alternatives: Capsules are handy but usually hold under 1 g each, so you need several.
Gelatin, bone broth, meat, fish, legumes.
Avoid with the antipsychotic clozapine. Otherwise few known interactions.
Well tolerated at a few grams a day; large doses can upset the stomach.
Pregnant, breastfeeding, on medication, or managing a health condition? Check with a doctor or pharmacist before starting a supplement.
Values checked: November 12, 2026.
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