Intervention
Glycine + N-Acetylcysteine (GlyNAC)
Last updated Sun May 17 2026 00:00:00 GMT+0000 (Coordinated Universal Time)
What it is
GlyNAC is a combination of two amino-acid-derived supplements:
- Glycine — the most abundant non-essential amino acid.
- N-Acetylcysteine (NAC) — a precursor to cysteine and downstream to glutathione.
Together they provide the substrates for endogenous glutathione (GSH), the master cellular antioxidant.
Why it’s of interest
GSH levels decline with age. The Kumar group at Baylor reported that 16 weeks of GlyNAC in older adults improved a wide range of measures: oxidative stress, mitochondrial function, inflammation, insulin resistance, body composition, gait speed, and cognition.
The trial was small and unblinded; replication and larger blinded RCTs are needed before drawing strong conclusions.
Mechanism
Restoring substrate availability for GSH synthesis raises tissue GSH and reduces downstream oxidative damage to lipids, proteins, and DNA.
Practical use
Trial protocols used dosing equivalent to ~100 mg/kg/day of each component, split through the day. Tolerability was reported as good.
Related entries
References
- Kumar, P. et al. Glycine and N-acetylcysteine (GlyNAC) supplementation in older adults: a clinical trial. J. Gerontol. A 78, 75–89 (2023).