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. Electrochemical evidences in oxidation of acetaminophen in the presence of glutathione and N acetylcysteine Chemical Communications (RSC Publishing) Dr. Laura E. Riley joined @GoodMorningAmerica recently to clear up some lingering confusion about Tylenol (acetaminophen) use during pregnancy. A new study from the University of London found that acetaminophen is safe Acetaminophen Induced Hepatotoxicity: a Comprehensive Update