Biological Variation of Coenzyme [Q.Sub.10] (Technical Briefs‪)‬

Coenzyme [Q.sub.10] ([CoQ.sub.10]) is an essential cofactor in the mitochondrial electron transport chain and is found in all cell membranes. It is present in the body in both the reduced and oxidized forms, with the reduced form ([CoQ.sub.10][H.sub.10]) having antioxidant properties. [CoQ.sub.10] has been implicated in disease processes, including Parkinson disease (1), diabetes (2), and Alzheimer disease (3), as well as in aging (4), oxidative stress (4, 5 ), and hydroxymethylglutaryl-CoA reductase inhibitor (statin) therapy (6). In particular, changes in [CoQ.sub.10] may be relevant to statininduced myalgia (7). Generally the bioavailability of dietary [CoQ.sub.10] is low, and the formulations of [CoQ.sub.10] supplements affect bioavailability (8,9). There is also a significant difference between individuals in absorption of [CoQ.sub.10] from supplements (9). Knowledge of the biological variation of [CoQ.sub.10] in healthy individuals enables interpretation of whether a significant change has occurred in response to a disease state or supplementation.