What is GlyNAC?
GlyNAC is a combination of glycine and N-acetylcysteine (NAC), two of glutathione's building blocks, studied as a way to correct glutathione deficiency in older adults. In a 16-week placebo-controlled trial in 24 older adults it corrected glutathione deficiency and improved oxidative stress, inflammation, gait speed and strength (Kumar 2023). A larger two-week trial found a benefit only in people with high oxidative stress and low glutathione (Lizzo 2022).
The idea
Older adults had lower red-cell glycine and cysteine and made glutathione more slowly than younger adults. Supplying both for two weeks raised their glutathione by about 95% and brought their oxidative stress markers into line with the younger group (Sekhar 2011). GlyNAC is the name later given to the glycine plus NAC combination.
The trials
An open-label pilot over 24 weeks corrected red-cell glutathione deficiency and improved strength, gait speed and cognition measures; the gains declined within 12 weeks of stopping (Kumar 2021). The 2023 placebo-controlled trial in 24 older adults reported improvements in glutathione, oxidative stress, mitochondrial function, inflammation and physical function (Kumar 2023).
A 2022 trial in 114 healthy older adults used 2.4, 4.8 or 7.2 g a day for two weeks. It did not raise glutathione across the whole group, its primary endpoint, but did in those with high oxidative stress and low starting glutathione at the two higher doses (Lizzo 2022).
What it does and doesn't tell us about cartilage
The GlyNAC trials measured blood, muscle function and whole-body markers, not cartilage. The cartilage evidence for NAC comes from cells and animals (Nakagawa 2010; Kaneko 2019). Gluthanol™ includes both GlyNAC ingredients, glycine and NAC, plus glutamine and alpha-lipoic acid; the GlyNAC trial results belong to those trials, not to Gluthanol.
Other questions people ask
What doses were used?
The 2022 trial used 2.4 to 7.2 g a day in total, in a 1:1 ratio of glycine to NAC (Lizzo 2022). The doses in the Kumar trials are not stated in their abstracts.
Is GlyNAC a brand?
No. It is the research name for the glycine and N-acetylcysteine combination.
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.
- Nakagawa S, Arai Y, Mazda O et al. N-acetylcysteine prevents nitric oxide-induced chondrocyte apoptosis and cartilage degeneration in an experimental model of osteoarthritis. J Orthop Res 2010.
- Kaneko Y, Tanigawa N, Sato Y et al. Oral administration of N-acetyl cysteine prevents osteoarthritis development and progression in a rat model. Sci Rep 2019.
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