Yes there is good evidence that acetaminophen (the active ingredient in Tylenol) can deplete glutathione under certain conditions. But whether that matters depends on dose, duration, and individual factors. Just say NO to Tylenol Tylenol And Glutathione Invigor Medical Frontiers Acetaminophen induced liver injury: Molecular mechanism and treatments from natural products Acetaminophen Toxicity: How Genetic Susceptibility Combines with Environmental Factors Liver injury induced by paracetamol and challenges associated with intentional and unintentional use