What Is Coenzyme Q10? How Does It Work, and What Are Its Health Effects?

Known names

• Ubiquinone
• Ubiquinol
• CoQ
• CoQ10
• UbiQgel™ (brand name)
• 2,3 dimethoxy-5 methyl-6-decaprenyl benzoquinone (scientific name)

What Is Coenzyme Q10?

Coenzyme Q10 (CoQ10), also known as ubiquinone, is a vitamin-like substance produced in all our cells and involved in synthesizing ATP, their basic energy building block. It is a powerful antioxidant, commonly tested for cardiovascular diseases, Parkinson disease and infertility, and claimed to protect against cancer.

Coenzymes are complex organic molecules that assist important biological transformations, such as a cell producing energy from oxygen and nutrients. Coenzyme q10 is a lipid component of the electron transport chain containing isoprene units. It is located in the inner mitochondrial membrane and transfers electrons received from complex 1 and complex 2 to complex 3.

What Are the Health Effects of Coenzyme Q10 Taken as a Supplement?

Coenzyme Q10 has not been shown to treat cancer or protect against/prevent it.

Coenzyme Q10 is naturally produced by the body’s cells. It is necessary for producing adenosine triphosphate (ATP), the fuel of living cells. In conditions where the heart lacks adequate blood supply (ischemia), such as a heart attack, CoQ10 has been found to reduce damage to heart tissue and cardiac mitochondria, where ATP is produced.

As an antioxidant, it is known to stabilize/protect cell and organelle membranes. In animal studies, coenzyme Q10 can neutralize free radicals that damage DNA and cells. However, orally administered coenzyme Q10 is poorly absorbed because it is a relatively large molecule. Studies have examined taking it with alpha-lipoic acid to improve oral bioavailability.

Because of its antioxidant activity, CoQ10 may reduce the effects of certain chemotherapy drugs and radiation treatment.

Medical Conditions in Which Coenzyme Q10 Has Been Tested, and Results

As an Antioxidant

Laboratory studies show that CoQ10 has antioxidant effects.

In Breast Cancer Treatment

In the 90s, there were a few case reports of breast cancer patients treated with high-dose CoQ10, but these studies were not followed up and their results could not be confirmed in larger studies.

In Cardiovascular Diseases

Several studies show that CoQ10 improves left ventricular (the heart’s pumping) function and reduces hypertension. Other studies produced negative results.

To Lower High Cholesterol

Clinical trials show inconsistent results in this area. Some studies report that Q10 raises “good” HDL cholesterol and lowers “bad” LDL cholesterol, but studies reporting the opposite predominate.

To Prevent Cardiac Toxicity from Anthracyclines

Anthracyclines, such as the chemotherapy drugs adriamycin and epirubicin, are known to have cardiac side effects. One clinical trial supports its use to reduce cardiac toxicity, but more studies are needed.

To Improve Athletic Performance

Clinical trials do not support its use for this purpose.

To Prevent Parkinson Disease Progression

A clinical trial shows that high-dose coenzyme Q10 slows Parkinson disease progression, but larger clinical trials are needed to support its use for this purpose.

In Huntington Disease Treatment

The single clinical trial conducted does not support its use for this purpose.

In Periodontal Disease Treatment (Oral and Dental Diseases)

Only one study supports its use for this purpose, but further clinical trials are needed.

In Infertility Treatment

Coenzyme Q10 improved sperm motility, but whether it can be used therapeutically for infertility remains unknown.

Do Not Use It in These Situations

• If you take the blood thinner warfarin (Coumadin), because CoQ10 may alter its effect
• If you are receiving chemotherapy, because CoQ10, being an antioxidant, may theoretically reduce chemotherapy effectiveness; consult your medical oncologist
• If you take theophylline, because CoQ10 delays its clearance from the body, potentially causing severe vomiting, heart rhythm disorders and persistent epileptic seizures

Side Effects

• Nausea
• Diarrhea
• Loss of appetite

Caution

A study in mice examined high-dose CoQ10 taken during treatment for non-small cell lung cancer and found that radiotherapy had reduced effectiveness. Patients must discuss this with their specialist when using CoQ10.

In conclusion, although some early studies suggest that coenzyme supplementation may be useful because of its antioxidant effects in high blood pressure, heart failure, heart muscle damage (myopathy) associated with cholesterol medications, and during chemotherapy for cancer, clinical studies have not clearly demonstrated benefits of coenzyme q10 supplementation for these conditions. There is also a risk of reducing chemotherapy and radiotherapy effectiveness when used during cancer treatment.

- Related topic: Antioxidants do not kill cancer; they trigger it