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 Acetaminophen induced liver injury: Molecular mechanism and treatments from natural products The role of oxidative stress, inflammation and acetaminophen exposure from birth to early childhood in the induction of autism William Parker, Chi Dang Hornik, Staci Bilbo, Zoie E. Holzknecht, Lauren Gentry, Should You stop Taking Tylenol (Acetaminophen, Paracetamol)