GlyNAC
GlyNAC is the combination of glycine and N-acetylcysteine (NAC), two glutathione precursors given together so cells have both glycine and cysteine for making glutathione.
Also called glycine and N-acetylcysteine, glycine plus NAC.
The combination grew out of work showing that older adults made glutathione more slowly and had lower red-cell glycine, cysteine and glutathione than younger adults, and that two weeks of cysteine and glycine restored their glutathione (Sekhar 2011).
In an open-label pilot in older adults, 24 weeks of GlyNAC corrected red-cell glutathione deficiency and oxidative stress and improved strength and gait speed; the gains declined within 12 weeks of stopping (Kumar 2021). In a 16-week randomised, placebo-controlled trial in 24 older adults, GlyNAC, and not placebo, corrected glutathione deficiency and improved oxidative stress, inflammation, gait speed and muscle strength (Kumar 2023).
A larger two-week trial in 114 healthy older adults found no rise in glutathione across the group, though it did rise in those who started with high oxidative stress and low glutathione (Lizzo 2022). None of these trials measured cartilage.
Sources
- Sekhar RV, Patel SG, Guthikonda AP et al. Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation. Am J Clin Nutr 2011.
- Kumar P, Liu C, Hsu JW et al. 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. Clin Transl Med 2021.
- Kumar P, Liu C, Suliburk J et al. 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. J Gerontol A Biol Sci Med Sci 2023.
- Lizzo G, Migliavacca E, Lamers D et al. A Randomized Controlled Clinical Trial in Healthy Older Adults to Determine Efficacy of Glycine and N-Acetylcysteine Supplementation on Glutathione Redox Status and Oxidative Damage. Front Aging 2022.
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