GlyNAC (Glycine + NAC): Aging Trials and Limits | Dose Track
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GlyNAC (Glycine and N-Acetylcysteine): half-life, strengths and approval status

Amounts studied · Approval status · Half-life notes

What is GlyNAC?

GlyNAC is a combination of the amino acid glycine and N-acetylcysteine (NAC), which the body uses as building blocks to make the antioxidant glutathione. It has been studied in older adults.

Also known as: glycine and NAC, glycine plus N-acetylcysteine, glycine N-acetylcysteine.

Amounts studied

A Nestlé trial compared 2.4, 4.8 and 7.2 g a day (equal parts glycine and NAC) for 2 weeks (Lizzo 2022). The Baylor trials gave GlyNAC for 16 to 24 weeks (Kumar 2021, Kumar 2023). These are study protocols, not a recommendation.

Approval status and how it is used

The NIH Dietary Supplement Label Database lists a glycine and N-acetyl L-cysteine ethyl ester product named GLYNAC-ET from Nutri as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling. Glycine and NAC also have their own pages.

What studies show: in an open-label pilot of 8 older adults with no placebo group, 24 weeks of GlyNAC raised red blood cell glutathione and improved strength, walking speed and other measures, and the gains faded after stopping (Kumar 2021). In a 16-week placebo-controlled trial in 24 older adults by the same Baylor group, GlyNAC improved glutathione, oxidative stress, insulin resistance and physical function compared with placebo (Kumar 2023). In a larger 2-week trial in 114 healthy older adults (average age 65), GlyNAC did not raise glutathione compared with placebo, the main goal; a subgroup with high oxidative stress and low glutathione did see an increase. Most of its authors worked for Nestlé, which holds patents and markets products for glycine and NAC (Lizzo 2022).

Safety: GlyNAC was safe and well tolerated in all three trials. The sources here do not describe drug interactions.

GlyNAC half-life and time to peak

  • Half-lifeNot listed
  • Time to peak (Tmax)Not listed

We could not find a single published half-life or time to peak for GlyNAC that applies to a supplement dose, so we do not list one.

How to track GlyNAC in Dose Track

  1. Add GlyNAC as a custom compound. Start typing its name and Dose Track fills in the details from its research library for you to check, and it sits next to everything else you take.
  2. Log each dose when you take it so your history shows exactly what you took and when.
  3. Set reminders on your own schedule, whether that is daily, weekly or every few days.
  4. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

How Dose Track handles peptides · Reconstitution calculator · Half-life calculator

Glycineaminoacetic acid NAC (N-Acetylcysteine)N-acetylcysteine, N-acetyl-L-cysteine GlutathioneGSH, reduced glutathione

Frequently asked questions

What is the half-life of GlyNAC?+
We could not find a single published half-life or time to peak for GlyNAC that applies to a supplement dose, so we do not list one.
Does GlyNAC slow aging?+
Two small trials from one group found better glutathione and physical function in older adults. A larger 2-week trial in 114 older adults found no rise in glutathione overall. Long-term effects on health are unknown.
Can I track GlyNAC in Dose Track?+
Yes. GlyNAC is in Dose Track's research library, so when you add it as a custom compound its details are filled in for you to check. You can then log each dose next to your other compounds, set reminders on your own schedule, and see your history next to your lab results. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

Sources

  1. Kumar P, 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;11(3):e372.
  2. Kumar P, 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;78(1):75-89.
  3. Lizzo G, 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;3:852569.
  4. NIH ODS Dietary Supplement Label Database. GLYNAC-ET 1050/100 mg (Nutri), glycine with N-acetyl L-cysteine ethyl ester, dietary supplement label, entered August 22, 2024; checked October 28, 2026.
  5. FDA. Questions and answers on dietary supplements.

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