Hi, Diane, this is one of those questions that is hard to answer. The short answer is that your body will store any NAC you give it as GSH. Cysteine itself can be toxic to the body, so the body stores it in a non-toxic form (GSH).

It is true that if I had a fungus ball, I would not inhale GSH. I think I might use oral GSH, but I'd have to think about it and figure out the pros and cons.