Supplementation with a combination of glycine and N acetylcysteine (precursors to glutathione) improved glutathione levels, oxidative stress, mitochondrial function, muscle strength, exercise capacity, cognition in older individuals. The supplement Antioxidant Precursor Molecule Could Improve Parkinson's Is N Acetylcysteine (NAC) Effective as Psychiatric and Neurological Treatment? Where Does the Evidence Lie? Differential effects of N acetylcysteine on retinal degeneration in two mouse models of normal tension glaucoma Cell Death & Disease The Importance of Glutathione in Health and Healing Dr. Todd Maderis The Power of NAC and Glutathione: Slowing Aging Naturally