GlyNAC: glycine plus NAC and the glutathione question

A small Baylor trial asked whether two amino acids could help older adults rebuild a key internal antioxidant. Here is what researchers found — and what remains unknown.

TL;DR

• GlyNAC combines glycine and N-acetylcysteine (NAC), the two raw materials the body needs to make glutathione, its primary internal antioxidant.
• A Baylor College of Medicine research group reported promising markers in a small 16-week trial with about 24 older adults — but the trial was small and needs replication.
• This is early-stage research; anyone considering GlyNAC supplementation should discuss it with a clinician first.

What is glynac

GlyNAC is a combination of two amino acids (in plain English: protein building blocks): glycine and N-acetylcysteine (NAC). Glycine is abundant in collagen-rich foods; NAC is a modified form of cysteine available as a supplement.

The pairing targets glutathione (in plain English: a molecule the body makes internally to neutralize harmful oxidants). Glutathione requires three amino acids — glycine, cysteine, and glutamate. Studies have found older adults tend to have lower glutathione than younger adults. The GlyNAC hypothesis: supplying two of those three building blocks directly may help the body rebuild production.

How does glynac work

Think of glutathione as the cell’s cleanup sponge. As we age, the body appears to make fewer sponges, in part because glycine and cysteine availability declines. GlyNAC supplies both precursors at once, which is the proposed mechanism researchers are studying.

Mitochondrial dysfunction (in plain English: reduced efficiency of the cell’s energy generators) is another area of interest in the GlyNAC literature. A 2021 pilot study from Baylor College of Medicine published in Clin Transl Med reported that GlyNAC supplementation in a small group of older adults was associated with improvements in glutathione levels and several markers of mitochondrial health. The pilot was uncontrolled and primarily designed to test feasibility.

What does glynac do for aging

The most-cited GlyNAC study is a randomized controlled trial published in the Journal of Gerontology: Biological Sciences (2023) from Rajagopal Sekhar’s group at Baylor College of Medicine. About 24 older adults were assigned to GlyNAC or placebo for 16 weeks. Researchers reported improvements in markers of oxidative stress (in plain English: cellular wear from reactive molecules), mitochondrial function, grip strength, walking speed, and cognitive test scores in the GlyNAC group.

Those findings are worth noting — and worth keeping in context. About 12 participants per group is a small sample for drawing firm conclusions. The trial was short, conducted at one site, and represents early exploratory research. Replication in larger, longer studies is needed. As with any supplement decision, a clinician who knows your health history is the right place to start.

Related reading:

• Ergothioneine: the ‘longevity vitamin’ from mushrooms
• Glucosamine and longevity: what the mortality data shows
• NAD+ and peptides: how longevity clinicians are combining protocols
• Spermidine: the autophagy nutrient in food
• Fisetin: the plant senolytic researchers study

FAQ

What is GlyNAC? GlyNAC is a combination of two amino acids — glycine and N-acetylcysteine (NAC). Both are building blocks of glutathione, one of the body’s main internal antioxidants. Researchers are testing whether supplying these precursors helps older adults restore glutathione levels that decline with age.

How does GlyNAC work? The working hypothesis is that older adults often have lower glutathione levels partly because glycine and cysteine availability declines. GlyNAC provides both precursors directly. Think of glutathione as the cell’s cleanup sponge — GlyNAC supplies the raw material to make more sponges.

What does GlyNAC do for aging, according to research? A small randomized trial at Baylor College of Medicine (~24 older adults, 16 weeks) reported improvements in markers of oxidative stress, mitochondrial function, physical strength, and cognition in the GlyNAC group. The trial was small and needs replication in larger studies before conclusions can be drawn.

Disclaimer

This article is educational and is not medical advice. Compounded medications are not FDA-approved. Clinical outcomes depend on individual factors and require physician evaluation. Results vary. Halftime Health is launching soon — join the waitlist to get updates.

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Sources

• GlyNAC supplementation in older adults: a randomized clinical trial — J Gerontol A Biol Sci Med Sci, 2023
• GlyNAC supplementation in older adults (pilot trial) — Clin Transl Med, 2021