GlyNAC (Glycine + N-Acetylcysteine)

GlyNAC pairs glycine with N-acetylcysteine (a cysteine donor) to supply both rate-limiting substrates for glutathione, the body's principal intracellular antioxidant, which falls with age. The rationale is that correcting glutathione deficiency reverses the downstream oxidative stress and mitochondrial dysfunction that accompany aging.

A series of pilot and randomised trials, largely from a Baylor College of Medicine group, report that GlyNAC in older adults raises glutathione and improves oxidative stress, mitochondrial function, insulin resistance, inflammation, endothelial function, gait speed, strength, and cognition, with some markers reverting toward youthful levels. The findings are promising but come from small trials by one group and await independent replication. Doses used are large, gram-level amounts of each amino acid.

Supplies glycine and cysteine, the two rate-limiting precursors for glutathione synthesis, restoring intracellular glutathione and lowering oxidative stress to improve mitochondrial function.