ABSTRACT 

Coenzyme Q10 (CoQ10) is a ubiquitous nutrient in human cells where it is essential for mitrochondrial energy production. CoQ10 exists in both an oxidized (ubiquinone) and reduced form (ubiquinol), with ubiquinol being the bioactive form.

In addition to its use in cellular ATP production ubiquinol acts as a powerful lipid-soluble antioxidant that protects lipid membranes and lipoproteins from oxidative stress. Lower circulating levels of ubiquinol are found in patients with cardiomyopathy and congestive heart failure (CHF) with deficiency being greater with increasing severity of disease.

CoQ10 supplementation is well tolerated and without toxicity or drug interactions and there is evidence to suggest that CoQ10 supplementation may provide clinical improvements for patients with CHF patients as well as for patients with hypertension, statin-induced myopathy and for those undergoing cardiac surgery.

Most research to date has focused on ubiquinone rather than ubiquinol, which has only recently become available as a supplemental nutrient. Effective doses of ubiquinol for congestive cardiac failure range from 100mg to 600mg/day yet most research to date has been limited to relatively small, short-term, and potentially biased trials that have used low doses of ubiquinone rather than ubiquinol.

The evidence of clinical benefits with CoQ10 supplementation in cardiovascular disease is largely inconclusive and further large-scale trials are required to determine if the higher bioavailability and more potent activity of ubiquinol produces better clinical responses than ubiquinone.

Ubiquinol therefore remains an interesting non-prescription, nutritional supplement that may be a useful adjunctive therapy for cardiac complaints despite not yet being recognized as a form of standard care.