I was a patient of Dr. Bishop for a while and still keep in contact with him. I saw him solely because of his GSH research. I used GSH supplements, not inhaled, for a while. I think very highly of Dr. Bishop and his ongoing work/research of GSH. I also felt that GSH probably helped, but i cannot say definitely one way or the other.
I do know that the FDA is a joke and that many here in the US are too worried about loosing funding or stepping on toes to do push anything. At least we have Europe who is willing to experiment, then once they prove its effectiveness we here in USA will start using it.