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. Acetaminophen and NSAID Toxicity Life Extension Tylenol's Impact on Glutathione and Liver Damage Acetaminophen induces liver injury and depletes glutathione in mice brain: Prevention by Moringa oleifera extract ScienceDirect Tylenol and Alcohol: The Dangers of Polydrug Abuse