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 Herbal Therapy for the Treatment of Acetaminophen Associated Liver Injury: Recent Advances and Future Perspectives Adaptation to acetaminophen exposure elicits major changes in expression and distribution of the hepatic proteome Scientific Reports Acetaminophen or Tylenol Toxicity Lect 19 Pharmacology