My husband, Ken, has been taking NADH for several years. When he first started it, he had to cut back on the sinemet or he would get faint and pass out (he has shy-drager syndrome) but this stopped soon. I do not know if it is really helpful now, but we are afraid to stop it. When our neurologist was first approached about it by a friend of ours, she said not to use it. To us she said we had nothing to lose by trying it, and more recently, she has said to people who ask that she really doesn't know but she has some patients who swear by it. Of course, she is one of the more open minded doctors I've come across. Barbara Smith, cg/Ken/70/17