Glycine
A simple amino acid studied for sleep quality and used as a building block.
Want to try Glycine?
See our pick — chosen for form and dose — in our professional dispensary. Please read Safety & interactions first.
Buy on Fullscript →You'll create a free Fullscript account and check out through our professional dispensary — 20% off retail.
We may earn a commission on Fullscript purchases, at no extra cost to you. Affiliate Disclosure
What it is
Glycine is the simplest amino acid, used to build proteins (including collagen) and acting as a calming neurotransmitter. It has a mildly sweet taste.
How it works
Glycine is the simplest amino acid, used to build proteins including collagen, and it acts as a calming neurotransmitter. Taken before bed it may slightly lower core body temperature and ease the transition to sleep, the basis for its sleep-quality use.
What it's been studied for
Taken to support sleep quality and relaxation.
What the evidence shows
Small studies suggest glycine taken before bed may improve subjective sleep quality and next-day alertness. The evidence base is small but the safety is excellent.
Who should consider it
It's used mainly for sleep quality and relaxation, and as a building block. It's very safe and mild, suiting people wanting a gentle, non-sedating sleep aid.
Amounts commonly studied
Sleep studies commonly use around 3 g before bed.
How to take it
Sleep studies commonly use around 3 g before bed. It's a mildly sweet powder that dissolves easily, or capsules. Timing (shortly before bed) matters for the sleep use.
Forms & absorption
Powder (dissolves easily, slightly sweet) or capsules.
Food sources
Meat, fish, dairy, legumes, and gelatin or bone broth (which are rich in glycine).
Safety & interactions
Very well tolerated with minimal side effects. Few known interactions.
Myths & what it won't do
Myth: glycine knocks you out. Reality: it's mild and non-sedating — it may improve sleep quality subtly rather than force sleep. Myth: the evidence is strong. Reality: it rests on small studies, though its excellent safety makes it low-risk to try.
Common questions
- Will glycine make me drowsy?
- It's non-sedating — rather than knocking you out, it may improve sleep quality when taken before bed.
- How much for sleep?
- Studies commonly use about 3 g shortly before bed.
- Is it safe?
- Very well tolerated with minimal side effects, which makes it low-risk to try.
The amounts listed here are what published research has used — not a prescription or a recommended dose for you. Confirm anything you plan to take with your own healthcare provider, especially if you take medications, are pregnant or nursing, or have a health condition.
Related goals
Research on Glycine
Recommendations on this page are informed by published research. This is educational information, not medical advice.
- Bannai M, Kawai N. New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep. J Pharmacol Sci. 2012;118(2):145-148. View study →Note: A review by researchers at Ajinomoto, a glycine manufacturer, summarizing their small studies of glycine before bed.