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I am a biologist/biochemist, a regular reader of this exchange and one who has Parkinson's. I feel badly that I have just been sitting and watching the discussion on NADH and not contributing what I know about it. There is little or nothing that I can tell you about its effect on the symptoms of Parkinson's Disease, but I agree with another correspondant who said there was no reason to be confused about things that are issues of fact. So here is some information. NADH is the "reduced" form of nicotinamide adenine dinucleotide or NAD. The two molecules differ from one another in a single hydrogen molecule, which is what the H symbolizes on NADH. These molecules are not enzymes. Enzymes are protein molecules which catalyze the many metabolic reactions which go on in our cells. NAD and NADH are smaller molecules that are readily able to be interconverted from one to the other as participants in many metabolic reactions in which a hydrogen atom is either removed from some other molecule and placed on NAD to make NADH or removed from NADH and placed on another molecule. Reactions in which hydrogen atoms are transferred from one molecule to another are called "oxidation-reduction reactions," and they are among the most common reactions in cells. In the conversion of food molecules (sugars and fats primarily) to energy, the food is oxidized, eventually being converted by many small steps to carbon dioxide and water. NAD and NADH participate in a number of those small steps. There are also reactions in which various molecules are being synthesized from smaller molecules in which oxidation and reduction are necessary, and in those cases NAD and NADH also sometimes take part. One of the most important places where NAD and NADH are constantly being changed back and forth from one to the other is in the mitochondria of our cells where the chemical energy from food molecules is being stored in ATP, another small molecule that participates in many metabolic reactions. A whole series of oxidation-reduction reactions in the mitochondria are together called the "electron transport chain." This chain begins with the oxidation of NADH (so it becomes NAD) and the reduction of another molecule called FMN (Flavin mononucleotide) which then becomes FMNH. Eventually the FMNH is converted back to FMN as Coenzyme Q is changed to Coenzyme QH. Then after a bunch of other reactions the Coenzyme QH is changed back to Coenzyme Q. Coenzyme Q or CoQ or Q or ubiquinone is another of those small molecules readily capable of oxidation and reduction. I mention all this, not because it is necessary to understanding NAD and NADH, but because there are many small molecules that are involved in oxidation reactions, they all have names, and the terminology can be confusing (as we have all discovered in working that through on the Parkinsn net). In addition, sometimes these molecules have more than one name. Twenty or thirty years ago NAD was called DPN and NADH was called DPNH. There is yet another molecule called NADP which also can be reduced with hydrogen to NADPH!!! So there is no end to the opportunities to be confused by the terminology. But here is the thing that is interesting to me: NADH and NAD are widely distributed in cells. They participate in a large number of reactions, many or most of which have no obvious connection to the metabolism of DOPA and DOPamine. If the Parkinson's were caused by a lack of NADH in general, we wouldn't have Parkinson's because we'd be dead. Our cells can't function without NAD and NADH. So if in fact NADH does have an effect on relieving our symptoms, it would be really interesting to know what specific thing was happening. It may be that there are those who have an idea what is going on there, but I confess that I haven't read the necessary papers. I DO know that the production of DOPA and DOPamine from the amino acid tyrosine involve some oxidation-reduction reactions, and I am going to do some more reading to see if there is a connection there. I hope this hasn't made things worse and more confusing. The bottom line is this: NADH is a molecule we all have in all our cells and which we use every moment to convert food into the energy that runs our bodies. If people have other questions about NAD and NADH, I will be glad to see what I can find out. I am a Ph.D., not an M.D., so I won't be able to make medical judgments, and I really have no idea what connection NADH has to our symptoms. BUT... the more we know, the closer we are. Donald Cronkite [log in to unmask] Department of Biology Hope College Box 9000 Holland, MI 49422-9000 USA