Is It Safe to Take Glutathione and Collagen Together? As a precursor to make glutathione, NAC has been used for decades both as an acute medication and as an over the counter supplement. Recently, the line between medication and supplement has been All About NAC (N acetylcysteine): What it is and what benefits it has Zenement N Acetyl Cysteine 100 mg Capsules 90 ct Effects of N acetylcysteine, oral glutathione (GSH) and a novel sublingual form of GSH on oxidative stress markers: A comparative crossover study. ScienceDirect