Coenzyme Q10 (PDQ®)

  • Coenzyme Q10 is a compound that is made naturally in the body. The body uses it for cell growth and to protect cells from damage that could lead to cancer (see Question 1).
  • Animal studies have shown that coenzyme Q10 helps the immune system work better and makes the body better able to resist certain infections and types of cancer (see Question 5).
  • Clinical trials have shown that coenzyme Q10 helps protect the heart from the damaging side effects of doxorubicin, a drug used to treat cancer (see Question 6).
  • In 3 small studies of coenzyme Q10 in breast cancer patients, some patients appeared to be helped by the treatment. Weaknesses in study design and reporting, however, made it unclear if benefits were caused by the coenzyme Q10 or by something else (see Question 6).
  • Coenzyme Q10 may not mix safely with other treatments. It is important that patients tell their health care providers about all therapies they are currently using or thinking of using (see Question 7).
  • Coenzyme Q10 has not been carefully tested in combination with chemotherapy to see if it is safe and effective. Because coenzyme Q10 is sold as a dietary supplement rather than a drug, it is not regulated by the US Food and Drug Administration (see Question 8).
What is coenzyme Q10?

Coenzyme Q10 is a compound that is made naturally in the body. The Q and the 10 in coenzyme Q10 refer to the groups of chemicals that make up the coenzyme. Coenzyme Q10 is also known by these other names:

  • CoQ10.
  • Q10.
  • Vitamin Q10.
  • Ubiquinone.
  • Ubidecarenone.

A coenzyme helps an enzyme do its job. An enzyme is a protein that speeds up the rate at which natural chemical reactions take place in cells of the body. The body's cells use coenzyme Q10 to make energy needed for the cells to grow and stay healthy. The body also uses coenzyme Q10 as an antioxidant. An antioxidant is a substance that protects cells from chemicals called free radicals. Free radicals can damage DNA (deoxyribonucleic acid). Genes, which are pieces of DNA, tell the cells how to work in the body and when to grow and divide. Damage to DNA has been linked to some kinds of cancer. By protecting cells against free radicals, antioxidants help protect the body against cancer.

Coenzyme Q10 is found in most body tissues. The highest amounts are found in the heart, liver, kidneys, and pancreas. The lowest amounts are found in the lungs. The amount of coenzyme Q10 in tissues decreases as people get older.

What is the history of the discovery and use of coenzyme Q10 as a complementary or alternative treatment for cancer?

Coenzyme Q10 was first identified in 1957. Its chemical structure was determined in 1958. Interest in coenzyme Q10 as a possible treatment for cancer began in 1961, when it was found that some cancer patients had a lower than normal amount of it in their blood. Low blood levels of coenzyme Q10 have been found in patients with myeloma, lymphoma, and cancers of the breast, lung, prostate, pancreas, colon, kidney, and head and neck.

Studies suggest that coenzyme Q10 may help the immune system work better. Partly because of this, coenzyme Q10 is used as adjuvant therapy for cancer. Adjuvant therapy is treatment given following the primary treatment to increase the chances of a cure.

What is the theory behind the claim that coenzyme Q10 is useful in treating cancer?

Coenzyme Q10 may be useful in treating cancer because it boosts the immune system. Also, studies suggest that CoQ10 analogs (drugs that are similar to CoQ10) may prevent the growth of cancer cells directly. As an antioxidant, coenzyme Q10 may help prevent cancer from developing.

Refer to the PDQ health professional summary on Coenzyme Q10 for more information on the theory behind the study of coenzyme Q10 in the treatment of cancer.

How is coenzyme Q10 administered?

Coenzyme Q10 is usually taken by mouth as a pill (tablet or capsule). It may also be given by injection into a vein (IV). In animal studies, coenzyme Q10 is given by injection.

Have any preclinical (laboratory or animal) studies been conducted using coenzyme Q10?

A number of preclinical studies have been done with coenzyme Q10. Research in a laboratory or using animals is done to find out if a drug, procedure, or treatment is likely to be useful in humans. These preclinical studies are done before any testing in humans is begun. Most laboratory studies of coenzyme Q10 have looked at its chemical structure and how it works in the body. The following has been reported from preclinical studies of coenzyme Q10 and cancer:

  • Animal studies found that coenzyme Q10 boosts the immune system and helps the body fight certain infections and types of cancer.
  • Coenzyme Q10 helped to protect the hearts of study animals that were given the anticancer drug doxorubicin, an anthracycline that can cause damage to the heart muscle.
  • Laboratory and animal studies have shown that analogs of coenzyme Q10 may stop cancer cells from growing.
Have any clinical trials (research studies with people) of coenzyme Q10 been conducted?

There have been no well-designed clinical trials involving large numbers of patients to study the use of coenzyme Q10 in cancer treatment. There have been some clinical trials with small numbers of people, but the way the studies were done and the amount of information reported made it unclear if benefits were caused by the coenzyme Q10 or by something else. Most of the trials were not randomized or controlled. Randomized controlled trials give the highest level of evidence:

  • In randomized trials, volunteers are assigned randomly (by chance) to one of 2 or more groups that compare different factors related to the treatment.
  • In controlled trials, one group (called the control group) does not receive the new treatment being studied. The control group is then compared to the groups that receive the new treatment, to see if the new treatment makes a difference.

Some research studies are published in scientific journals. Most scientific journals have experts who review research reports before they are published, to make sure that the evidence and conclusions are sound. This is called peer review. Studies published in peer-reviewed scientific journals are considered better evidence. No randomized clinical trials of coenzyme Q10 as a treatment for cancer have been published in a peer-reviewed scientific journal.

The following has been reported from studies of coenzyme Q10 in people:

Randomized trials of coenzyme Q10 and doxorubicin

  • A randomized trial of 20 children treated for acute lymphoblastic leukemia or non-Hodgkin lymphoma looked at whether coenzyme Q10 would protect the heart from the damage caused by the anthracycline drug doxorubicin. The results of this trial and others have shown that coenzyme Q10 decreases the harmful effects of doxorubicin on the heart.
  • In a larger trial, 236 patients treated for breast cancer were randomized to receive oral supplements of either 300 mg Coenzyme Q10 or placebo, each combined with 300 IU vitamin E, for 24 weeks. The study found that levels of fatigue and quality of life were not improved in patients who received coenzyme Q10 plus vitamin E compared to patients who received the placebo.

Studies of coenzyme Q10 as an adjuvant therapy for breast cancer

Small studies have been done on the use of coenzyme Q10 after standard treatment in patients with breast cancer:

  • In a study of coenzyme Q10 in 32 breast cancer patients, it was reported that some signs and symptoms of cancer went away in 6 patients. Details were given for only 3 of the 6 patients. The researchers also reported that all the patients in the study used less pain medicine, had improved quality of life, and did not lose weight during treatment.
  • In another study led by the same researchers, 3 breast cancer patients were given high-dose coenzyme Q10 and followed for 3 to 5 years. The study reported that one patient had complete remission of cancer that had spread to the liver, another had remission of cancer that had spread to the chest wall, and the third had no breast cancer found after surgery.

It is not clear, however, if the benefits reported in these studies were caused by coenzyme Q10 therapy or something else. The studies had the following weaknesses:

  • The studies were not randomized or controlled.
  • The patients used other supplements in addition to coenzyme Q10.
  • The patients received standard treatments before or during the coenzyme Q10 therapy.
  • Details were not reported for all patients in the studies.

Anecdotal reports of coenzyme Q10

Anecdotal reports are incomplete descriptions of the medical and treatment history of one or more patients. There have been anecdotal reports that coenzyme Q10 has helped some cancer patients live longer, including patients with cancers of the pancreas, lung, colon, rectum, and prostate. The patients described in these reports, however, also received treatments other than coenzyme Q10, including chemotherapy, radiation therapy, and surgery.

In a follow-up study, two patients who had breast cancer remaining after surgery were treated with coenzyme Q10 for 3 to 4 months. It was reported that after treatment with coenzyme Q10, the cancer was completely gone in both patients.

Have any side effects or risks been reported from coenzyme Q10?

No serious side effects have been reported from the use of coenzyme Q10. The most common side effects include the following:

  • Insomnia (being unable to fall sleep or stay asleep).
  • Higher than normal levels of liver enzymes.
  • Rashes.
  • Nausea.
  • Pain in the upper part of the abdomen.
  • Dizziness.
  • Feeling sensitive to light.
  • Feeling irritable.
  • Headache.
  • Heartburn.
  • Feeling very tired.

It is important to check with health care providers to find out if coenzyme Q10 can be safely used along with other drugs. Certain drugs, such as those that are used to lower cholesterol, blood pressure, or blood sugar levels, may decrease the effects of coenzyme Q10. Coenzyme Q10 may change way the body uses warfarin (a drug that prevents the blood from clotting) and insulin.

As noted in Question 1, the body uses coenzyme Q10 as an antioxidant. Antioxidants protect cells from free radicals. Some conventional cancer therapies, such as anticancer drugs and radiation treatment, kill cancer cells in part by causing free radicals to form. Researchers are studying whether using coenzyme Q10 along with conventional therapies has any effect, good or bad, on the way these conventional therapies work in the body.

Is coenzyme Q10 approved by the US Food and Drug Administration (FDA) for use as a cancer treatment in the United States?

Coenzyme Q10 is sold as a dietary supplement and is not approved by the FDA for use as a cancer treatment. In the United States, dietary supplements are regulated as foods, not drugs. This means that approval by the FDA is not required before coenzyme Q10 is sold, unless specific health claims are made about the supplement. Also, the way companies make coenzyme Q10 is not regulated. Different batches and brands of coenzyme Q10 supplements may be different from each other.

Check NCI’s list of cancer clinical trials for cancer CAM clinical trials on coenzyme Q10 that are actively enrolling patients.

General information about clinical trials is available from the NCI Web site.

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.

Changes were made to this summary to match those made to the health professional version.

Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.

PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.

This PDQ cancer information summary has current information about the use of coenzyme Q10 in the treatment of people with cancer. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Date Last Modified") is the date of the most recent change.

The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Cancer Complementary and Alternative Medicine Editorial Board.

A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Clinical trials are listed in PDQ and can be found online at NCI's Web site. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237).

PDQ is a registered trademark. The content of PDQ documents can be used freely as text. It cannot be identified as an NCI PDQ cancer information summary unless the whole summary is shown and it is updated regularly. However, a user would be allowed to write a sentence such as “NCI’s PDQ cancer information summary about breast cancer prevention states the risks in the following way: [include excerpt from the summary].”

The best way to cite this PDQ summary is:

National Cancer Institute: PDQ® Coenzyme Q10. Bethesda, MD: National Cancer Institute. Date last modified <MM/DD/YYYY>. Available at: http://www.cancer.gov/cancertopics/pdq/cam/coenzymeQ10/patient. Accessed <MM/DD/YYYY>.

Images in this summary are used with permission of the author(s), artist, and/or publisher for use in the PDQ summaries only. If you want to use an image from a PDQ summary and you are not using the whole summary, you must get permission from the owner. It cannot be given by the National Cancer Institute. Information about using the images in this summary, along with many other images related to cancer can be found in Visuals Online. Visuals Online is a collection of more than 2,000 scientific images.

The information in these summaries should not be used to make decisions about insurance reimbursement. More information on insurance coverage is available on Cancer.gov on the Coping with Cancer: Financial, Insurance, and Legal Information page.

More information about contacting us or receiving help with the Cancer.gov Web site can be found on our Contact Us for Help page. Questions can also be submitted to Cancer.gov through the Web site’s Contact Form.

Complementary and alternative medicine (CAM)—also referred to as integrative medicine—includes a broad range of healing philosophies, approaches, and therapies. A therapy is generally called complementary when it is used in addition to conventional treatments; it is often called alternative when it is used instead of conventional treatment. (Conventional treatments are those that are widely accepted and practiced by the mainstream medical community.) Depending on how they are used, some therapies can be considered either complementary or alternative. Complementary and alternative therapies are used in an effort to prevent illness, reduce stress, prevent or reduce side effects and symptoms, or control or cure disease.

Unlike conventional treatments for cancer, complementary and alternative therapies are often not covered by insurance companies. Patients should check with their insurance provider to find out about coverage for complementary and alternative therapies.

Cancer patients considering complementary and alternative therapies should discuss this decision with their doctor, nurse, or pharmacist as they would any therapeutic approach, because some complementary and alternative therapies may interfere with their standard treatment or may be harmful when used with conventional treatment.

It is important that the same rigorous scientific evaluation used to assess conventional approaches be used to evaluate CAM therapies. The National Cancer Institute (NCI) and the National Center for Complementary and Alternative Medicine (NCCAM) are sponsoring a number of clinical trials (research studies) at medical centers to evaluate CAM therapies for cancer.

Conventional approaches to cancer treatment have generally been studied for safety and effectiveness through a rigorous scientific process that includes clinical trials with large numbers of patients. Less is known about the safety and effectiveness of complementary and alternative methods. Few CAM therapies have undergone rigorous evaluation. A small number of CAM therapies originally considered to be purely alternative approaches are finding a place in cancer treatment—not as cures, but as complementary therapies that may help patients feel better and recover faster. One example is acupuncture. According to a panel of experts at a National Institutes of Health (NIH) Consensus Conference in November 1997, acupuncture has been found to be effective in the management of chemotherapy-associated nausea and vomiting and in controlling pain associated with surgery. In contrast, some approaches, such as the use of laetrile, have been studied and found ineffective or potentially harmful.

The NCI Best Case Series Program, which was started in 1991, is one way CAM approaches that are being used in practice are being investigated. The program is overseen by the NCI’s Office of Cancer Complementary and Alternative Medicine (OCCAM). Health care professionals who offer alternative cancer therapies submit their patients’ medical records and related materials to OCCAM. OCCAM conducts a critical review of the materials and develops follow-up research strategies for approaches deemed to warrant NCI-initiated research.

When considering complementary and alternative therapies, patients should ask their health care provider the following questions:

  • What side effects can be expected?
  • What are the risks associated with this therapy?
  • Do the known benefits outweigh the risks?
  • What benefits can be expected from this therapy?
  • Will the therapy interfere with conventional treatment?
  • Is this therapy part of a clinical trial?
  • If so, who is sponsoring the trial?
  • Will the therapy be covered by health insurance?

National Center for Complementary and Alternative Medicine (NCCAM)

The National Center for Complementary and Alternative Medicine (NCCAM) at the National Institutes of Health (NIH) facilitates research and evaluation of complementary and alternative practices, and provides information about a variety of approaches to health professionals and the public.

  • NCCAM Clearinghouse
  • Post Office Box 7923 Gaithersburg, MD 20898–7923
  • Telephone: 1–888–644–6226 (toll free) 301–519–3153 (for International callers)
  • TTY (for deaf and hard of hearing callers): 1–866–464–3615
  • Fax: 1–866–464–3616
  • E-mail: info@nccam.nih.gov

CAM on PubMed

NCCAM and the NIH National Library of Medicine (NLM) jointly developed CAM on PubMed, a free and easy-to-use search tool for finding CAM-related journal citations. As a subset of the NLM's PubMed bibliographic database, CAM on PubMed features more than 230,000 references and abstracts for CAM-related articles from scientific journals. This database also provides links to the Web sites of over 1,800 journals, allowing users to view full-text articles. (A subscription or other fee may be required to access full-text articles.) CAM on PubMed is available through the NCCAM Web site. It can also be accessed through NLM PubMed bibliographic database by selecting the "Limits" tab and choosing "Complementary Medicine" as a subset.

Office of Cancer Complementary and Alternative Medicine

The NCI Office of Cancer Complementary and Alternative Medicine (OCCAM) coordinates the activities of the NCI in the area of complementary and alternative medicine (CAM). OCCAM supports CAM cancer research and provides information about cancer-related CAM to health providers and the general public via the NCI Web site.

National Cancer Institute (NCI) Cancer Information Service

U.S. residents may call the NCI Cancer Information Service toll free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 8:00 am to 8:00 pm. A trained Cancer Information Specialist is available to answer your questions.

Food and Drug Administration

The Food and Drug Administration (FDA) regulates drugs and medical devices to ensure that they are safe and effective.

  • Food and Drug Administration
  • 5600 Fishers Lane
  • Rockville, MD 20857
  • Telephone: 1–888–463–6332 (toll free)

Federal Trade Commission

The Federal Trade Commission (FTC) enforces consumer protection laws. Publications available from the FTC include:

  • Who Cares: Sources of Information About Health Care Products and Services
  • Fraudulent Health Claims: Don’t Be Fooled
  • Consumer Response Center
  • Federal Trade Commission
  • CRC-240
  • Washington, DC 20580
  • Telephone: 1-877-FTC-HELP (1-877-382-4357) (toll free)
  • TTY (for deaf and hearing impaired callers): 202-326-2502
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