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. Oxidative stress mediates end organ damage in a novel model of acetaminophen toxicity in Drosophila Scientific Reports Tylenol, Autism, And The Glutathione Connection OC Integrative Medicine Electrochemical evidences in oxidation of acetaminophen in the presence of glutathione and N acetylcysteine Chemical Communications (RSC Publishing)