This cancer information summary provides an overview of the use of coenzyme Q10 in cancer therapy. The summary includes a history of coenzyme Q10 research, a review of laboratory studies, and data from investigations involving human subjects. Although several naturally occurring forms of coenzyme Q have been identified, Q10 is the predominant form found in humans and most mammals, and it is the form most studied for therapeutic potential. Thus, it will be the only form of coenzyme Q discussed in this summary.
This summary contains the following key information:
Many of the medical and scientific terms used in the summary are hypertext linked (at first use in each section) to the NCI Dictionary of Cancer Terms, which is oriented toward nonexperts. When a linked term is clicked, a definition will appear in a separate window.
Reference citations in some PDQ cancer information summaries may include links to external websites that are operated by individuals or organizations for the purpose of marketing or advocating the use of specific treatments or products. These reference citations are included for informational purposes only. Their inclusion should not be viewed as an endorsement of the content of the websites, or of any treatment or product, by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board or the National Cancer Institute.
Coenzyme Q10 (also known as CoQ10, Q10, vitamin Q10, ubiquinone, and ubidecarenone) is a benzoquinone compound synthesized naturally by the human body. The "Q" and the "10" in the name refer to the quinone chemical group and the 10 isoprenyl subunits that are part of this compound's structure. The term "coenzyme" denotes it as an organic (contains carbon atoms), nonprotein molecule necessary for the proper functioning of its protein partner (an enzyme or an enzyme complex). Coenzyme Q10 is used by cells of the body in a process known variously as:
Through this process, mitochondria produce energy for cell growth and maintenance.[
Coenzyme Q10 is present in most tissues, but the highest concentrations are found in the following organs:[
The lowest concentration is found in the lungs.[
Given the importance of coenzyme Q10 in optimizing cellular energy production, use of this compound as a treatment for diseases other than cancer has been explored. Most of these investigations have focused on coenzyme Q10 as a treatment for cardiovascular disease.[
Stimulation of the immune system by this compound has also been observed in animal studies and in humans without cancer.[
While coenzyme Q10 may show indirect anticancer activity through its effect(s) on the immune system, there is evidence to suggest that analogs of this compound can suppress cancer growth directly. Analogs of coenzyme Q10 have been shown to inhibit the proliferation of cancer cells in vitro and the growth of cancer cells transplanted into rats and mice.[
Several companies distribute coenzyme Q10 as a dietary supplement. In the United States, dietary supplements are regulated as foods, not drugs. Therefore, premarket evaluation and approval by the U.S. Food and Drug Administration (FDA) are not required unless specific disease prevention or treatment claims are made. The FDA can, however, remove from the market dietary supplements that it deems unsafe. Because dietary supplements are not formally reviewed for manufacturing consistency, ingredients may vary considerably from lot to lot and there is no guarantee that ingredients claimed on product labels are present (or are present in the specified amounts). The FDA has not approved coenzyme Q10 for the treatment of cancer or any other medical condition.
To conduct clinical drug research in the United States, researchers must file an Investigational New Drug (IND) application with the FDA. The IND application process is highly confidential, and IND information can be disclosed only by the applicants. No investigators have announced that they have applied for an IND to study coenzyme Q10 as a treatment for cancer.
In animal studies, coenzyme Q10 has been administered by injection (intravenous, intraperitoneal, intramuscular, or subcutaneous). In humans, it is usually taken orally as a pill (gel bead or capsule), but intravenous infusions have been given.[
Coenzyme Q10 was first isolated in 1957, and its chemical structure (benzoquinone compound) was determined in 1958.[
A large amount of laboratory and animal data on coenzyme Q10 have accumulated since 1962.[
Proposed mechanisms of action for coenzyme Q10 that are relevant to cancer include its essential function in cellular energy production and its stimulation of the immune system (which may both be related), as well as its role as an antioxidant. Coenzyme Q10 is essential to aerobic energy production,[
Laboratory work on coenzyme Q10 has focused primarily on its structure and its function in cell respiration. Studies in animals have demonstrated that coenzyme Q10 is capable of stimulating the immune system, with treated animals showing increased resistance to protozoal infections [
Researchers in one study sounded a cautionary note when they found that coadministration of coenzyme Q10 and radiation therapy decreased the effectiveness of the radiation therapy.[
Clinical studies on the use of coenzyme Q10 to prevent side effects of cancer treatment, treat side effects of cancer treatment, and/or as a treatment for cancer are very limited. Importantly, clinical trials that examined the use of coenzyme Q10 during cancer treatment to prevent toxicities have not followed patients for long-term outcomes to determine whether coenzyme Q10 decreased the efficacy of cancer treatments (e.g., chemotherapy and radiation therapy). A recent observational study conducted with 1,134 patients with breast cancer enrolled in an National Cancer Institute multi-institution clinical trial (SWOG S0221) suggested that the use of antioxidant supplements, including coenzyme Q10, prior to and during cancer treatment may be associated with increased recurrence rates and decreased survival.[
Symptom and Side Effect Management
In view of promising results from animal studies, coenzyme Q10 was tested as a protective agent against cardiac toxicity that was observed in cancer patients treated with the anthracycline drug doxorubicin. It has been postulated that doxorubicin interferes with energy-generating biochemical reactions that involve coenzyme Q10 in heart muscle mitochondria and that this interference can be overcome by coenzyme Q10 supplementation.[
Two randomized, controlled trials have explored the potential of coenzyme Q10 -containing supplements to prevent or treat fatigue in patients who received cancer therapy. A randomized, placebo-controlled trial of 236 patients with breast cancer who received adjuvant chemotherapy with or without radiation therapy concluded that coenzyme Q10 at a daily dose of 300 mg combined with 300 IU of vitamin E, divided into three doses, did not prevent treatment-induced worsening of mean fatigue levels or quality of life after 24 weeks of supplementation.[
The use of coenzyme Q10 as a treatment for cancer in humans has been investigated in only a limited manner. In view of observations that blood levels of coenzyme Q10 are frequently reduced in cancer patients,[
In a follow-up study, one of six patients with a reported remission and one new patient were treated for several months with higher doses of coenzyme Q10 (390 mg/day and 300 mg/day, respectively).[
In another report by the same investigators, three patients with breast cancer who received high-dose coenzyme Q10 (390 mg/day) were followed for a total of 3 to 5 years.[
All three of the above-mentioned human studies [
Anecdotal reports of coenzyme Q10 lengthening the survival of patients with pancreatic, lung, rectal, laryngeal, colon, and prostate cancers also exist in the peer-reviewed scientific literature.[
Current Clinical Trials
Use our advanced clinical trial search to find NCI-supported cancer clinical trials that are now enrolling patients. The search can be narrowed by location of the trial, type of treatment, name of the drug, and other criteria. General information about clinical trials is also available.
No serious toxicity associated with the use of coenzyme Q10 has been reported.[
In a prospective study that explored the association between supplement use and breast cancer outcomes (SWOG S0221), the use of any antioxidant supplement before and during treatment–including coenzyme Q10, vitamin A, vitamin C, vitamin E, and carotenoids–was associated with a trend showing an increased hazard of recurrence (adjusted hazard ratio, 1.41; confidence interval, 0.98–2.04, P = .06).[
Certain lipid -lowering drugs, such as the statins (lovastatin, pravastatin, and simvastatin) and gemfibrozil, as well as oral agents that lower blood sugar, such as glyburide and tolazamide, cause a decrease in serum levels of coenzyme Q10 and reduce the effects of coenzyme Q10 supplementation.[
To assist readers in evaluating the results of human studies of integrative, alternative, and complementary therapies for cancer, the strength of the evidence (i.e., the "levels of evidence ") associated with each type of treatment is provided whenever possible. To qualify for a level of evidence analysis, a study must:
Separate levels of evidence scores are assigned to qualifying human studies on the basis of statistical strength of the study design and scientific strength of the treatment outcomes (i.e., endpoints) measured. The resulting two scores are then combined to produce an overall score. A table showing the levels of evidence scores for qualifying human studies cited in this summary is presented below. For an explanation of the scores and additional information about levels of evidence analysis of integrative, alternative, and complementary therapies for cancer, refer to Levels of Evidence for Human Studies of Integrative, Alternative, and Complementary Therapies.
|Reference Number||Statistical Strength of Study Design||Strength of Endpoints Measured||Combined Score|
||3iii Nonconsecutive case series||Diii Indirect surrogates -- tumor response rate||3iiiDiii|
The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
Editorial changes were made to this summary.
This summary is written and maintained by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, which is editorially independent of NCI. The summary reflects an independent review of the literature and does not represent a policy statement of NCI or NIH. More information about summary policies and the role of the PDQ Editorial Boards in maintaining the PDQ summaries can be found on the About This PDQ Summary and PDQ® - NCI's Comprehensive Cancer Database pages.
Purpose of This Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the use of coenzyme Q10 in the treatment of people with cancer. It is intended as a resource to inform and assist clinicians in the care of their patients. It does not provide formal guidelines or recommendations for making health care decisions.
Reviewers and Updates
This summary is reviewed regularly and updated as necessary by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, which is editorially independent of the National Cancer Institute (NCI). The summary reflects an independent review of the literature and does not represent a policy statement of NCI or the National Institutes of Health (NIH).
Board members review recently published articles each month to determine whether an article should:
Changes to the summaries are made through a consensus process in which Board members evaluate the strength of the evidence in the published articles and determine how the article should be included in the summary.
Any comments or questions about the summary content should be submitted to Cancer.gov through the NCI website's Email Us. Do not contact the individual Board Members with questions or comments about the summaries. Board members will not respond to individual inquiries.
Levels of Evidence
Some of the reference citations in this summary are accompanied by a level-of-evidence designation. These designations are intended to help readers assess the strength of the evidence supporting the use of specific interventions or approaches. The PDQ Integrative, Alternative, and Complementary Therapies Editorial Board uses a formal evidence ranking system in developing its level-of-evidence designations.
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The preferred citation for this PDQ summary is:
PDQ® Integrative, Alternative, and Complementary Therapies Editorial Board. PDQ Coenzyme Q10. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/about-cancer/treatment/cam/hp/coenzyme-q10-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389329]
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Last Revised: 2021-06-23
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