Coenzyme Q10 (CoQ10), also known as ubiquinone, is involved in cellular respiration and energy production. It is found in all human cells, with higher concentrations in the liver, kidney, heart, and pancreas. It is also consumed as a dietary supplement for its antioxidant effects and is often promoted as a preventive agent for cardiovascular diseases, Parkinson's disease, infertility and cancer.
Studies done in mice indicate antioxidant and neuroprotective effects (17) (18).
Data from clinical trials suggest beneficial effects of CoQ10 in patients with coronary artery disease (2) and congestive heart failure (21).
CoQ10 supplementation may increase sperm motility in asthenozoospermic men (8) and reduce fatigue induced by physical exertion (9).
Putative neuroprotective effects of CoQ10 were reported in patients with progressive supranuclear palsy (5) as well as those with early Parkinson's disease (6), but not with midstage Parkinson's disease (7). A mixture of antioxidants, including CoQ10, vitamins C, E, and lipoic acid was found ineffective against Alzheimer's disease (20).
There may be a role for CoQ10 in the prevention of migraine (22). A small study showed a reduction in the frequency of migraine headaches with CoQ10 supplementation (23), but a randomized trial failed to find benefit (24). More research is warranted.
The observation that patients who receive statin therapy have decreased concentrations of CoQ10 in muscle cells (25) resulted recently in studies to evaluate the benefit of CoQ10 in alleviating statin-induced myalgias. The data are inconclusive (26) (27) (28).
CoQ10 has also been investigated for anticancer effects. A few case reports suggest that CoQ10 supplementation may be useful in the treatment of breast cancer (3) (4). However, a randomized trial did not find any effectiveness in improving self-reported fatigue or quality of life in breast cancer patients (29). Further study is needed.
CoQ10 is structurally similar to vitamin K and can antagonize the effects of warfarin (11) (12).
And because of its antioxidant property, CoQ10 may also reduce effectiveness of chemotherapy and radiation therapy (13).