coenzyme Q10


What Is It?
Health Benefits
Dosage Information
Guidelines for Use
General Interaction
Possible Side Effects

Evidence Based Rating Scale

What Is It?

One of the world's most popular supplements, the chemical coenzyme Q10 has generated great excitement as a heart disease remedy and a cure for countless other conditions. The body naturally produces this compound, which has been dubbed "vitamin Q" because of its essential role in keeping all systems running smoothly. In fact, the scientists who identified coenzyme Q10 in 1957 initially honored its ubiquitous presence--it's found in every human cell and in all living organisms--by naming it "ubiquinone." Small amounts are also present in most foods.

A member of a family of compounds called quinones, coenzyme Q10 (sometimes called Co Q10) works in concert with enzymes (hence the name "coenzyme") that are necessary for chemical reactions throughout the body. It is particularly abundant in high-energy-demanding cells, such as those found in the heart. In addition, coenzyme Q10 acts as a powerful antioxidant to prevent the cellular damage caused by unstable oxygen molecules called free radicals.

Health Benefits 

Extravagant claims have been made for coenzyme Q10, many of which require further investigation. Still under examination, for example, is whether it can truly slow the progress of Parkinson's disease, boost stamina in AIDS patients, stabilize blood sugar levels in diabetes sufferers, enhance athletic ability, improve circulation in Raynaud's disease, fight allergies and stave off the retina deterioration associated with macular degeneration. Skeptics also question the value of taking coenzyme Q10 in pill form. They contend that it loses its potency while traveling through the digestive tract.

On the other hand, there is evidence to indicate that coenzyme Q10 does work for certain disorders. Most importantly, it appears to support the heart muscle's strenuous efforts to beat 100,000 times a day. Without adequate levels of this enzyme, the heart muscle can become weaker and less efficient at pumping blood through the body. Coenzyme Q10's popularity as a heart supplement is well established in countries such as Sweden, Italy, and Canada. In Japan, up to 10% of adults take coenzyme Q10 regularly.

Specifically, coenzyme Q10 may help to:

·  Treat heart disease, especially congestive heart failure. Heart disease sufferers tend to be relatively deficient in coenzyme Q10. When levels are boosted by supplements, heart function appears to be enhanced. In addition, the compound's antioxidant properties may inhibit artery-clogging plaque buildup and potentially fatal blood clots.

People with congestive heart failure, in which a weakened heart pumps inefficiently, may stand to benefit the most from coenzyme Q10 supplements. In a 12-month placebo-controlled trial of more than 2,500 people suffering from this disease, 80% experienced an improvement in symptoms--less ankle swelling and shortness of breath, and better color and sleep habits--when they supplemented their standard medications with a daily 100 mg dose of coenzyme Q10 (1). They were also far less likely than placebo-takers to require hospitalization for their condition. Rates of death from the disease did not change, however. Recent research suggests that it may even be a useful adjunctive therapy for those awaiting heart transplant surgery. Study participants showed a decrease in the 6-min walk test and a decrease in dyspnea, New York Heart Association (NYHA) classification, nocturia, and fatigue (2).

Not all studies have reported benefits, though. In a recent six-month trial of 46 individuals with moderate to severe congestive heart failure, those assigned to take coenzyme Q10 (rather than a placebo) experienced no apparent improvement in heart function or symptom relief. Clearly more research is needed to prove conclusively that coenzyme Q10 is effective for this potentially fatal disease.

·  Treat angina and arrhythmias. The intense chest pain known as angina may occur less frequently under the influence of coenzyme Q10's heart-enhancing actions. In lightening the heart's workload and steadying heart rhythm, coenzyme Q10 may be particularly useful for people who suffer from irregular heart beats (arrhythmias) following a heart attack. Scientists have found that people suffering from coronary artery disease have very low levels of coenzyme Q10 (3). More research is needed to determine whether this relationship is causal, however because of the low risk of side effects supplementation with co Q10 is widely used by people suffering from this condition.

·  Control high blood pressure. More than a third of people suffering from high blood pressure--a serious but symptom-free ailment known as the silent killer--are believed to have inadequate amounts of coenzyme Q10. Taking the supplement regularly may help to lower elevated blood pressure and protect against complications of the disease (4, 5).

·  Prevent and treat cancer. Coenzyme Q10's antioxidant actions can be enlisted to stop the free-radical damage believed to cause certain cancers. Several small studies have shown a benefit for people with breast or prostate cancer (6, 7). Other findings indicate that coenzyme Q10 boosts the immune system, possibly helping to limit the spread of cancerous tissue. However, a report issued by the Agency for Healthcare Research and Quality (AHRQ) has issued a report advising that co Q10 shows no discernable benefit in the treatment of cancer (8). Clearly more research is needed.

·  Counter Alzheimer's disease and memory loss, and provide general anti-aging benefits. Because the body's production of coenzyme Q10 slows with age, some doctors routinely recommend the supplement to anyone over age 50. Indeed, many people take it as a general energy enhancer; others take it to fight age-related memory loss. Its antioxidant actions have even been enlisted to slow the progression of Alzheimer's disease, a memory-robbing, degenerative disease most common in older individuals (8). Further research is needed to flesh out exactly how supplemental coenzyme Q10 and its antioxidant properties might positively affect the aging process.

·   Diminish the effects of Parkinson’s disease. Researchers are beginning to elucidate the many factors that influence the progression of Parkinson’s disease. Recent findings have shown that oxidative damage and impaired cellular processing may speed the progression of this disease. Coenzyme Q10 may help to slow this loss of control at the cellular level (8, 9).

·   Fight weight gain, chronic fatigue syndrome, fibromyalgia, the side effects of chemotherapy, and HIV/AIDS. In addition to being a powerful antioxidant, coenzyme Q10 helps provide the spark that generates the body's energy on a very basic, cellular level. Without adequate stores of this nutrient, the body will have fewer resources with which to fight off frequently debilitating disorders such as chronic fatigue and fibromylagia and the negative side effects experienced during treatment with chemotherapy (10). Even HIV infection may benefit. Getting adequate stores of the nutrient can, at a minimum, help ensure proper muscle function and overall stamina. Smooth energy use on the cellular level may also help in countering weight gain.

·  Treat gum disease. For people with periodontal disease who must undergo oral surgery, low doses of coenzyme Q10 may promote healing. The supplement is also thought to limit post-surgery gum pain and bleeding. A 1995 review of coenzyme Q10 concluded that there was little sound evidence to support this use, however (12).

·  Complement cholesterol-lowering statin drugs. Coenzyme Q10 is an essential supplement when using statin drugs such as Lipitor, Pravachol, Lescol, and Zocor. While blocking the liver mechanism that manufactures cholesterol, statins also block the production of coenzyme Q10 (13, 14). Although the long-term effect of this is unknown, some nutritionally oriented doctors have asked the FDA to attach a warning label to statin prescriptions. In Europe many physicians routinely prescribe coenzyme Q10 as a supplement for anyone taking a statin drug.

Note: Coenzyme Q10 has also been found to be useful for a number of other disorders. For information on these additional ailments, see our Dosage Recommendations Chart for Coenzyme Q10.


Co enzyme Q 10 comes in several forms. The Ubiquinone form is the most common and some manufacturers have designed gel capsules or chewable tablets that have better absorption. The Ubiquinol form, while more expensive, has been reported to be more bioavailable and therefore might be more useful in seriuous conditions such as Parkinson's disease and congestive heart failure.

  • tablet
  • softgel
  • liquid
  • capsule

Dosage Information


·  For congestive heart failure, angina, fibromyalgia, and symptoms of Alzheimer's disease: Take 100 mg twice a day.

·  For arrhythmias, high blood pressure, anti-aging actions, gum disease, and cancer prevention: Take 60 mg twice a day.

·  For supplementing conventional cancer therapy: Take 200 mg every morning.

·  For complementing a statin drug: Take 60 mg every morning.


Be sure to check our our Dosage Recommendations Chart for Coenzyme Q10, which lists therapeutic dosages for specific ailments at a glance.

Guidelines for Use

·  Take coenzyme Q10 with food. As a fat-soluble compound, it is absorbed most efficiently when consumed with a food containing some fat, such as peanut butter. For the same reason, look for capsules or tablets that contain coenzyme Q10 in an oil base (such as soybean or another oil).

·  Keep coenzyme Q10 out of direct light. Store it in a cool area (but not the freezer).

·  You may have to take coenzyme Q10 for two months or more before seeing any improvement in your condition.

·  The supplement can be expensive (a daily dose of 100 mg can cost about $40 a month). Shop around for the lowest price on a quality product.

General Interaction


·   Certain heart medications--statins for high cholesterol, beta-blockers for high blood pressure--may deplete or in other ways lower coenzyme Q10 levels in the body. Ask your doctor about supplementing your heart-treatment regimen with coenzyme Q10.

·   There are no other known drug or nutrient interactions associated with coenzyme Q10.

Possible Side Effects

·   Side effects are uncommon, even at high doses.

·   Rarely, coenzyme Q10 can cause nausea, diarrhea, upset stomach, headache or appetite loss.



·  Heart disease is a serious condition. If you suffer from it, talk to your doctor about taking coenzyme Q10 along with conventional medications. It should never be used as a substitute for proven therapies.

·  If you are pregnant or breast-feeding, don't take coenzyme Q10 supplements; its safety in this group of women has not been established.



1.      Baggio E, Gandini R, Plancher AC, Passeri M, Carmosino G. Italian multicenter study on the safety and efficacy of coenzyme Q10 as adjunctive therapy in heart failure. CoQ10 Drug Surveillance Investigators. Mol Aspects Med. 1994;15 Suppl:s287-94.

2.      Berman M, Erman A, Ben-Gal T, Dvir D, Georghiou GP, Stamler A, Vered Y, Vidne BA, Aravot D. Coenzyme Q10 in patients with end-stage heart failure awaiting cardiac transplantation: a randomized, placebo-controlled study. Clin Cardiol. 2004 May;27(5):295-9.

3.      Yalcin A, Kilinc E, Sagcan A, Kultursay H. Coenzyme Q10 concentrations in coronary artery disease. Clin Biochem. 2004 Aug;37(8):706-9.

4.      Rosenfeldt F, Hilton D, Pepe S, Krum H. Systematic review of effect of coenzyme Q10 in physical exercise, hypertension and heart failure. Biofactors. 2003;18(1-4):91-100.

5.      Wilburn AJ, King DS, Glisson J, Rockhold RW, Wofford MR. The natural treatment of hypertension. J Clin Hypertens (Greenwich). 2004 May;6(5):242-8.


Date Published: 09/08/2005
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