Coenzyme Q10 Overview

Coenzyme Q 10 (CoQ 10 ), also known as ubiquinone, is a major part of the body's mechanism for producing energy. The name of this supplement comes from the word ubiquitous, which means "found everywhere." Indeed, CoQ 10 is found in every cell in the body. It plays a fundamental role in the mitochondria, the parts of the cell that produce energy from glucose and fatty acids.

Japanese scientists first reported therapeutic properties of CoQ 10 in the 1960s. Some evidence suggests that CoQ 10 might assist the heart during times of stress on the heart muscle, perhaps by helping it use energy more efficiently.

CoQ 10 's best-established use is for congestive heart failure, but the evidence that it works is not entirely consistent. Ongoing research suggests that it may also be useful for other types of heart problems, Parkinson's disease, and several additional illnesses. It is generally used in addition to, rather than instead of, standard therapies.

CoQ 10 supplementation might also be of value for counteracting side effects of certain prescription medications.

Every cell in your body needs CoQ 10 , but there is no dietary requirement as the body can manufacture CoQ 10 from scratch.

The typical recommended dosage of CoQ 10 is 30 mg to 300 mg daily; higher daily intakes have been used in some studies.

CoQ 10 is fat soluble and may be better absorbed when taken in an oil-based soft gel form rather than in a dry form such as tablets and capsules. ¹ Dividing the total daily dosage up into two or more separate doses may produce higher blood levels. ² A finely ground up (“nanoparticular”) form of the supplement appears to be much better absorbed than standard CoQ 10 products. ³

Congestive Heart Failure

Most but not all studies tell us that CoQ 10 can be helpful for people with congestive heart failure (CHF). In this serious condition, the heart muscles become weakened, resulting in poor circulation and shortness of breath.

People with CHF have significantly lower levels of CoQ 10 in heart muscle cells than do healthy people. ⁴ This fact alone does not prove that the supplements will help CHF; however, it prompted medical researchers to try using CoQ 10 as a treatment for heart failure.

The largest study was a 1-year, double-blind, placebo-controlled trial of 641 people with moderate to severe congestive heart failure. ⁵ Half were given 2 mg per kilogram body weight of CoQ 10 daily; the rest were given placebo. Standard therapy was continued in both groups. The participants treated with CoQ 10 experienced a significant reduction in the severity of their symptoms. No such improvement was seen in the placebo group. The people who took CoQ 10 also had significantly fewer hospitalizations for heart failure.

Similarly positive results were also seen in other double-blind studies involving a total of more than 270 participants. ⁶ One double-blind study found that in people with heart failure so severe they were waiting for a heart transplant, use of CoQ 10 improved subjective symptoms. ⁷ However, two very well-designed double-blind studies published in 1999 and 2000 enrolling a total of about 85 people with congestive heart failure failed to find any evidence of benefit. ⁸ The reason for this discrepancy is not clear.

Cardiomyopathy

Cardiomyopathy is the general name given to conditions in which the heart muscle gradually becomes diseased. Several small studies suggest that CoQ 10 supplements are helpful for some forms of cardiomyopathy. ^{9 10}

Hypertension

An 8-week, double-blind, placebo-controlled study of 59 men already taking medications for high blood pressure found that 120 mg daily of CoQ 10 reduced blood pressure by about 9% as compared to placebo. ¹¹ A 12-week, double-blind, placebo-controlled study of 83 people with isolated systolic hypertension (a type of high blood pressure in which only the "top" number is high) found that use of CoQ 10 at a dose of 60 mg daily improved blood pressure measurements to a similar extent. ¹² Similarly, in a 12-week, double-blind, placebo-controlled trial of 74 people with diabetes, use of CoQ 10 at a dose of 100 mg twice daily significantly reduced blood pressure as compared to placebo. ¹³ Antihypertensive effects were also seen in previous smaller trials, most of which were not double-blind. ^{14 15}

Heart Attack Recovery

In a double-blind trial, 144 people who had recently experienced a heart attack were given either placebo or 120 mg of CoQ 10 daily for 1 year, along with conventional treatment. ¹⁶ The results showed that participants receiving CoQ 10 experienced significantly fewer heart-related problems, such as episodes of angina pectoris or arrhythmia, or recurrent heart attacks.

A double-blind study of 49 people who had suffered a full cardiac arrest requiring cardiopulmonary resuscitation (CPR) found that use of CoQ 10 along with mild hypothermia (chilling of the body) was more effective than mild hypothermia plus placebo. ¹⁷

Note:Individuals recovering from a heart attack should not take any herbs or supplements except under the supervision of a physician.

Parkinson’s Disease

A study published in 2002 raised hopes that CoQ 10 might help slow the progression of Parkinson’s disease. In this 16-month, double-blind, placebo-controlled trial, 80 people with Parkinson’s disease were given either CoQ 10 (at a dose of 300 mg, 600 mg, or 1,200 mg daily) or placebo. ¹⁸ Participants in this trial had early stages of the disease and did not yet need medication. The results appeared to suggest that CoQ 10 , especially at the highest dose, might have slowed disease progression. However, for a variety of statistical reasons, the results were in fact quite inconclusive.

A subsequent double-blind, placebo-controlled study of 28 people with Parkinson’s disease, which was well-controlled by medications, indicated that 360 mg of CoQ 10 daily could produce a mild improvement in some symptoms. ¹⁹ Based on these results, a more substantial study was undertaken, enrolling 131 people with Parkinson’s disease (again, well-controlled by medications). ²⁰ This repeat trial used a specially finely ground up form of CoQ 10 that, though taken at a dose of only 300 mg daily, produced blood levels of the supplement equivalent to those produced by 1,200 mg daily of ordinary CoQ 10 . Unfortunately, it didn’t work. While benefits were seen in both the placebo and the CoQ 10 group, CoQ 10 failed to prove moreeffective than placebo.

Further trials will be necessary to confirm (or deny) these results.

Diabetes

In the 12-week, double-blind, placebo-controlled trial of 74 people with diabetes mentioned above, use of CoQ 10 at a dose of 100 mg twice daily significantly improved blood sugar control as compared to placebo. ²¹ Similar benefits were seen in the 8-week, double-blind, placebo-controlled study of 59 men also described above. ²² However, a third study failed to find any effect on blood sugar control. ²³

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