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. Sex differences in glutathione metabolism and acetaminophen toxicity 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 Use During Pregnancy and Autism Risk Acetaminophen Toxicity: How Genetic Susceptibility Combines with Environmental Factors