Glycine is a non-essential amino acid (meaning that it can be made in the body and is not required from the diet) which acts as a neurotransmitter. Although glycine supplements are sometimes promoted as having a calming effect or improving sleep, the studies supporting these claims have been small, short-term, and involved a company which sells glycine. For more details, see the full answer >>

For more information, see the Encyclopedia article about Glycine.

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April 5, 2018

Perhaps ConsumerLab could fund a research to verify sleep results, and publish abstract at PubMed, with full study readable only for paying ConsumerLab members?

Main problem with previous sleep studies:
* Very short time (7 days or less), so there is no information is there tolerance or should Glycine be cycled (on, off, so not taking 3g every night).
* Only 3g dose tested. Why not compare for example 3g, 6g and 9g.
* Industry funded studies.
* What was the placebo? Glycine is a sweet amino acid. In industry funded studies, perhaps the employees were able to taste glycine vs. placebo.
Quite soluble to water, solubility is 25g of glycine to 100mL water, at 25 Celcius temperature.
* Seems to work for both men and women, but was it tested with different age groups of adults, for example 20y, 40y, 60y, 80y?

Glycine is VERY cheap, so at least that is not a problem. Carlson Labs, Glycine, Amino Acid Powder, 3.53 oz (100 g), costs about $5 for consumers per 100g. That would mean about $5 per month per person, if taken 3g/day.
April 5, 2018

Hi Jarkko - Thank you for your comment and suggestion; ConsumerLab does a lot of laboratory testing of products, but we don't conduct clinical studies.

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