OTC Nutraceuticals

Glycine (amino acid, GlyNAC)

inflammation redox

Sold as a consumer product in 1 of 9 markets tracked; in clinical trials in 1.

Evidence so far is from 3 human trials with no pre-planned main endpoint and laboratory and animal studies. 1 other study gave a different intervention (Isoflavone-enriched soybean leaf extract) and is shown for context, not counted.

In people: 3 trials (68 people, 12-36 weeks). Doses studied: 1.31 mmol/kg/day glycine and 0.83 mmol/kg/day NAC; 1.33 mmol/kg/day glycine plus 0.81 mmol/kg/day N-acetylcysteine; 100 mg/kg/day each of glycine and NAC.

Evidence map

each mark is a study; size shows participants; hover, tap or focus for details

main endpoints improvedno effectworsenedmixedobservationalanother intervention, contextsize not reported

Higher rows are closer to a person taking this. A case that rests only on the lower rows rests on animals or cells.

What each study measured

outlined square: the main (primary) endpoint

Harms reported

human studies

Where it is available

by regulator; select a market for its source

If you are tracking this yourself

measures the human studies used, by how repeatable they are

Repeatability is whether the same person measured twice gets the same number. It is not statistical significance. It informs study or protocol design only, never advice for a person.

What would change this picture

each study's own statement

Trials under way

Every study (8)

T6 Kumar 2023a Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Physical Function, and Aging Hallmarks: A Randomized Clinical Trial doi:10.1093/gerona/glac135
T6 Kumar 2020 Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical Trial doi:10.3390/biomedicines8100390
T6 Kumar 2021 Glycine and N‐acetylcysteine (GlyNAC) supplementation in older adults improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, insulin resistance, endothelial dysfunction, genotoxicity, muscle strength, and cognition: Results of a pilot clinical trial doi:10.1002/ctm2.372
T3 Do 2026 Neuroprotective effects of isoflavone-enriched soybean leaves (Glycine Max) on scopolamine-induced memory deficits in C57BL/6 mice via antioxidative mechanisms doi:10.3389/fnagi.2026.1787268
T3 Tonna 1964 An Autoradiographic Evaluation of the Aging Cellular Phase of Mouse Skeleton Using Tritiated Glycine doi:10.1093/geronj/19.2.198
T3 Kumar 2023b GlyNAC (Glycine and N-Acetylcysteine) Supplementation in Old Mice Improves Brain Glutathione Deficiency, Oxidative Stress, Glucose Uptake, Mitochondrial Dysfunction, Genomic Damage, Inflammation and Neurotrophic Factors to Reverse Age-Associated Cognitive Decline: Implications for Improving Brain Health in Aging doi:10.3390/antiox12051042
T0 Li 2022 Genetically predicted circulating levels of glycine, glutamate, and serotonin in relation to the risks of three major neurodegenerative diseases: A Mendelian randomization analysis doi:10.3389/fnagi.2022.938408
TX Wang 2026 Glycine and N-acetylcysteine supplementation, with or without exercise, in brain health and functional aging: implications for sarcopenia and frailty in older adults doi:10.3389/fnut.2026.1775264