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. Frontiers Acetaminophen induced liver injury: Molecular mechanism and treatments from natural products Tylenol, Autism, And The Glutathione Connection OC Integrative Medicine Tylenol's Impact on Glutathione and Liver Damage