Coenzyme Q-10

Other Name(s):

Co Q-10, Q-10, ubiquinone, ubiquinol

General Description:

Coenzyme Q-10 is a fat-soluble quinone similar in structure to vitamins E and K. Since its discovery 40 years ago, research has been ongoing to evaluate its reported cardiac benefits. Coenzyme Q-10 is synthesized by cells throughout the body, hence its name ubiquinone; ubi because it is ubiquitous throughout the body and quinone because it is chemically a quinone with a side chain.

Q-10 acts as a catalyst in the respiratory chain that creates energy from carbohydrates. It is abundant in cell membranes, particularly in the mitochondria.

Coenzyme Q-10 is a powerful antioxidant by itself and in combination with vitamin E.

Levels of coenzyme Q-10 decrease with age and are reportedly low in patients with heart disease. The amount of coenzyme Q-10 in the body peaks around age 20 and then decreases. Strenuous physical activity also accelerates coenzyme Q-10 turnover, thereby decreasing levels.

Organ meats such as heart, lung, kidney, spleen, liver, pancreas and adrenals are good sources of coenzyme Q-10.

Medically Valid Uses:

Coenzyme Q-10 has been studied as a possible agent for use in congestive heart failure (CHF) and certain cardiomyopathies (heart diseases). In several ongoing studies (outside the United States), coenzyme Q-10 has become part of the standard treatment of CHF and cardiomyopathy because coenzyme Q-10 appears to have a beneficial effect and there are apparently no serious side effects or toxicity associated with its use.

Unsubstantiated Claims:

Please note that this section reports on claims that have NOT yet been substantiated through scientific studies.

Coenzyme Q-10 is claimed to possibly help prevent LDL oxidation (thereby decreasing development of atherosclerosis), re-perfusion injury following open-heart surgery and hepatotoxicity associated with cholesterol-lowering drug (lovastatin). Q-10 has also been used to improve exercise tolerance/athletic performance, improve control of blood sugar in diabetes and help boost the immune system to fight infectious disease (when used alone or in combination with vitamin B6). It is also believed to help increase fat metabolism.

Some other claims suggest that Q-10 may also play a role in the treatment of gingivitis and other periodontal diseases, breast cancer, chronic stable angina, mitral valve prolapse, heartbeat irregularities, hypertension, Parkinson's disease/neurodegenerative disease and muscular dystrophy.

Dosing Format:

Supplements range from 10 to 300 mg. There is no scientifically established dose; however, doses of 30 to 100 mg per day have been suggested. Higher doses have been used for the treatment of diseases such as those listed above. This supplement should be taken with a meal containing some fat to improve its absorption (coenzyme Q-10 is poorly absorbed from the gastrointestinal tract).

Women who are pregnant or breast-feeding should consult a physician before taking any dietary supplements.

Side Effects, Toxicity and Interactions:

No toxicity has been reported with supplements up to 600 mg for every kg of body weight. Minor side effects that may occur with supplementation (but are unusual) include a burning sensation in the mouth, loss of appetite, nausea, diarrhea, insomnia, rashes, dizziness, irritability, fatigue, heartburn, headache, light sensitivity, and abdominal pain.

Cholesterol-lowering drugs such as lovastatin block the natural synthesis of coenzyme Q-10, so supplementation of 100 mg/day is recommended while taking these drugs.

Additional Information:

Click here for a list of reputable Web sites with general information on nutrition.


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  9. Sacher HL, Sacher ML, Landau SW, Kersten R, Dooley F, Sacher A, Sacher M, Dietrick K, Ichkhan K. The clinical and hemodynamic effects of coenzyme q10 in congestive cardiomyopathy. Am J Ther. 1997 Feb 1;4(2/3):66-72.

  10. Folkers K, Langsjoen P, Willis R, Richardson P, Xia LJ, Ye CQ, Tamagawa H. Lovastatin decreases coenzyme Q levels in humans. Proc Natl Acad Sci U.S.A. 1990 Nov;87(22):8931-4.

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  12. Langsjoen H, Langsjoen P, Langsjoen P, Willis R, Folkers K. Usefulness of coenzyme Q10 in clinical cardiology: a long-term study. Mol Aspects Med. 1994;15 Suppl:s165-75.

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