Glycine: A Powerful Amino Acid for Midlife Women's Health 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 Immunomodulatory and antitumor effects of shilajit and glycine: Natural metabolic modulators targeting breast and liver cancer Cells need a steady supply of antioxidants to defend themselves, and glutathione is the body's master defender. Yet, daily stress and ageing can deplete glutathione faster than we can make it. NAC + The amino acid glycine Purovitalis