NADH (also known as coenzyme 1 or codehydrogenase 1) is a natural coenzyme found widely in nature and involved in numerous enzyme reactions. Although it is present in every human cell, NADH is not considered an essential nutrient because it is synthesized from niacinamide (vitamin B-3) in the body. Consequently, NADH deficiency is rarely found outside the presence of vitamin B-3 deficiency. Dietary sources of NADH include meat, fish, poultry, and yeast. It is also available as a supplement.
As a coenzyme, NADH participates in many biochemical reactions in the body. It is required for the manufacture of adenosine triphosphate (ATP), the principal source of energy for all cellular functions. In the brain, NADH plays an important role in the production of vital neurotransmitters, including dopamine, norepinepherine, and epinepherine.
The most commonly recommended dose for NADH is 10 mg per day, but clinical studies on NADH have used up to 50 mg per day with no significant side-effects. Although studies have shown no toxic effects with up to a year or more of use, the safety of long-term NADH use has not been evaluated.