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Glycine is a protein that is needed for brain function. It has been used to enhance mental function, lower blood pressure, and control blood glucose. Glycine can be taken as a pill or powder. It can also be applied to the skin as a cream.


3 to 15 grams daily

What Research Shows

May Be Effective

  • Metabolic syndrome —may lower blood pressure B1

Not Enough Data to Assess

  • Diabetes A1
  • Psychotic disorders C1

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to take glycine in small doses for a short time. Not enough studies have been done to say whether it is safe to take for a long period. It is also not known whether it is safe to take by women who are pregnant or breastfeeding.


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.



A. Diabetes

A1. Guasch-Ferré M, Hruby A, et al. Metabolomics in Prediabetes and Diabetes: A Systematic Review and Meta-analysis. Diabetes Care. 2016 May;39(5):833-846.

B. Metabolic Syndrome

B1. Díaz-Flores M, Cruz M, et al. Oral supplementation with glycine reduces oxidative stress in patients with metabolic syndrome, improving their systolic blood pressure. Can J Physiol Pharmacol. 2013;91(10):855-860.

C. Psychotic Disorders

C1. Hoenders HJR, Bartels-Velthuis AA, et al. Natural Medicines for Psychotic Disorders: A Systematic Review. J Nerv Ment Dis. 2018 Feb;206(2):81-101.

Last reviewed February 2020 by EBSCO NAT Review Board Eric Hurwitz, DC  Last Updated: 5/27/2020