Coenzyme Q10, or CoQ10, is not an antioxidant although it is characterized as such in all of the commercial available products. Coenzyme Q10 is the oxidized form of this substance and an oxidant can never ever be an antioxidant. However, when Co Q10 is absorbed into the organism it is reduced by NADH and thus, becomes an antioxidant. In other words, NADH makes Coenzyme Q-10 in the body into an antioxidant; hence, CoQ10 needs NADH to become effective. Additionally, Co Q10 concentrations may be increased with NADH supplements . If you take commercially available coenzyme Q10 without an equivalent dose of NADH, you may deplete the cell from NADH and thereby make the cell energy deficient and prone to degeneration.
This fact implies two consequences: the intake of commercially available CoQ10 is not very meaningful unless the organism has sufficient ammounts of cellular NADH available to reduce Co Q10 and make it an antioxidant.