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. Exposure to acetaminophen and all its metabolites upon 10, 15, and 20 mg kg intravenous acetaminophen in very preterm infants Pediatric Research Acetaminophen Toxicity: How Genetic Susceptibility Combines with Environmental Factors Acetaminophen or Tylenol Toxicity Lect 19 Pharmacology Tylenol And Glutathione Invigor Medical