Health Reference LibraryHow much glycine should I take, and can you take too much?
This entry is part of the Nutri Tailor Health Reference Library — cited research on supplements, nutrients and adjacent areas of health.
Summary
Three grams before bed is the dose the sleep research used, and it is the only dose with evidence behind it for that purpose, so if sleep is the reason there is no point taking less. For general use alongside collagen or on a plant based diet, 1 to 3 g a day is the range. Glycine is not essential and the body makes it, there is no reference intake and no upper limit, and 9 g a day has been used for months in trials without notable harm; mild stomach upset is the usual complaint. Six of the 470 mg capsules reach the research dose, which is why a powder is more practical if you take it nightly.
Dose calculator: capsules to reach your glycine target
Enter the daily amount of glycine you are aiming for and see how many servings of each Nutri Tailor product reach it. Nothing you enter leaves this device. No AI is used.
This tool does arithmetic on the label figures. It is not personal dosing advice and it knows nothing about your history or blood results. The reference intake, the safe upper guide and the trial doses are on this page; talk to your GP or a registered nutritional therapist before changing what you take.
Effective dose
The reference intake is none; glycine is not an essential amino acid, the body makes it and a mixed diet supplies about 2 g a day. The sleep research used 3 g of glycine taken shortly before bed, which is six of the 470 mg capsules or a teaspoon of powder, and it is the dose to copy if sleep is the reason. There is no evidence that less does anything for sleep and no evidence that more does more. For general intake, 1 to 3 g a day is the range people use alongside a collagen product or on a plant based diet.
Safety profile
How much is too much: no upper limit has been set; the trials used up to 9 g a day for months without notable harm, and the usual dose is a third of that. Glycine is one of the safest amino acids in the literature: 9 g a day has been used for months in trials without notable harm, and the common complaint at any dose is mild stomach upset or loose stools. It tastes sweet, so a large powder dose is easy to take. Anyone with kidney disease should ask their GP before adding several grams of any single amino acid.
Guideline positions
NHS vitamins and minerals guidance for glycine. NIH Office of Dietary Supplements fact sheet for glycine where one exists. The trial doses quoted above are from the sources listed on this page.
Practical framework
Capsules to reach the dose, from the Nutri Tailor range, all made in the UK: [glycine capsules](/products/glycine), 470 mg per capsule, so six capsules give the 2.8 g the sleep research used; a powder is more practical at that dose. To read your own result against the UK ranges, use the free blood test result interpreter. This is a summary of published research, not personal health advice. Talk to your GP or a registered nutritional therapist before changing what you take, especially if you are pregnant, have a diagnosed condition or are under ongoing care.
Common misconceptions
That more glycine works faster: above the doses the trials used there is no extra effect, only more side effects. That the front of the bottle states the dose: read the per capsule figure and the serving size on the back. That the NHS figure is a toxic threshold: it is the level below which harm is unlikely, which is a different thing.
Sources
- 2026. Does glycine help sleep and what dose did the research use?. Nutri Tailor Health Reference Library.