Your comment is loaded with good information. Thanks. Hoffer was doing research on NAD, which was the only form of the coenzyme available, and I think he wasn’t actively researching it by the time NADH became commercially available, Hoffer had more or less retired. Here’s what he had to say about NADH: From Doctoryourself.com NAD and NADH are interconvertable in the body. This suggests that the active form is the reduced form, NADH, and that NAD is much less effective since it would first have to be reduced to NADH. The decreasing order of therapeutic efficacy would be NADH, NAD and finally vitamin B3. There would be no formation of NADH in the stomach from NAD, but there would be some made in the intestine. “I hope these recent Birkmayer studies will reactivate interest in the therapeutic effect of this potent coenzyme made from vitamin B3. It is available from Menuco Corporation, 350 Fifth Avenue, Suite 7509, New York, NY 10118.