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Coenzyme Q10 (CoQ10): In Depth


What’s the Bottom Line?

How much do we know about CoQ10?

We have some information from high quality studies done in people about the safety and effectiveness of CoQ10 for different conditions.

What do we know about the effectiveness of CoQ10?

CoQ10 supplements may benefit some patients with cardiovascular disorders, but research on other conditions is not conclusive.

What do we know about the safety of CoQ10?

CoQ10 has mild side effects and is generally well tolerated. However, it may make warfarin, an anticoagulant (blood thinner), less effective.

What Is CoQ10 and Why Is It Important?

Coenzyme Q10 (CoQ10) is an antioxidant that is necessary for cells to function properly. It is found in plants, bacteria, animals, and people. Cells use CoQ10 to make the energy they need to grow and stay healthy. CoQ10 can be found in highest amounts in the heart, liver, kidneys, and pancreas. Levels of CoQ10 decrease as you age.

More information

What the Science Says About the Effectiveness of CoQ10

CoQ10 supplements may benefit some patients with cardiovascular disorders. Researchers have also looked at the effects of CoQ10 for drug-induced muscle weakness, reproductive disorders, cancer, and other diseases. However, results from these studies are limited and not conclusive.

The following information highlights the research status on CoQ10 for the conditions for which it has been studied.

Heart Conditions

Muscle Weakness From Statins (Cholesterol-lowering Drugs)

Reproductive Disorders


Other Research on CoQ10

What the Science Says About the Safety and Side Effects of CoQ10

  • Studies have not reported serious side effects related to CoQ10 use.
  • The most common side effects of CoQ10 include insomnia, increased liver enzymes, rashes, nausea, upper abdominal pain, dizziness, sensitivity to light, irritability, headaches, heartburn, and fatigue.
  • CoQ10 should not be used by women who are pregnant or breastfeeding.
  • Statins may lower the levels of CoQ10 in the blood. However, it is unclear what type of health effect this may have on an individual.
  • CoQ10 may make warfarin, an anticoagulant (blood thinner), less effective.

National Institutes of Health (NIH)-Funded Research

NIH is currently sponsoring studies investigating the effects of CoQ10 on mild-to-moderate muscle pain in people who take statins, fertility in older women, and breast cancer treatments.

More To Consider

  • Do not use CoQ10 supplements to replace a healthful diet or conventional medical care, or as a reason to postpone seeing a health care provider about a medical problem.
  • If you're thinking about using a dietary supplement, first get information on it from reliable sources. Keep in mind that dietary supplements may interact with medications or other supplements and may contain ingredients not listed on the label. Your health care provider can advise you.
  • If you're pregnant or nursing a child, or if you are considering giving a child a dietary supplement, it is especially important to consult your (or your child’s) health care provider.
  • Look for published research studies on CoQ10 for the health condition that interests you.
  • Tell all your health care providers about any complementary health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

For More Information

NCCIH Clearinghouse

The NCCIH Clearinghouse provides information on NCCIH and complementary and integrative health approaches, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.

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A service of the National Library of Medicine, PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals. For guidance from NCCIH on using PubMed, see How To Find Information About Complementary Health Approaches on PubMed.

NIH Clinical Research Trials and You

The National Institutes of Health (NIH) has created a Web site, NIH Clinical Research Trials and You, to help people learn about clinical trials, why they matter, and how to participate. The site includes questions and answers about clinical trials, guidance on how to find clinical trials through and other resources, and stories about the personal experiences of clinical trial participants. Clinical trials are necessary to find better ways to prevent, diagnose, and treat diseases.

Research Portfolio Online Reporting Tools Expenditures & Results (RePORTER)

RePORTER is a database of information on federally funded scientific and medical research projects being conducted at research institutions.


To provide resources that help answer health questions, MedlinePlus (a service of the National Library of Medicine) brings together authoritative information from the National Institutes of Health as well as other Government agencies and health-related organizations.

Key References

Other References


NCCIH thanks the following people for their technical expertise and review of this publication: Ryan Bradley, N.D., M.P.H, Bastyr University; Paul Thompson, M.D., Hartford Hospital; Jeffrey D. White, M.D., National Cancer Institute; and John (Jack) Killen, Jr., M.D. and Wendy Weber, N.D., Ph.D., M.P.H., NCCIH.

This publication is not copyrighted and is in the public domain. Duplication is encouraged.

NCCIH has provided this material for your information. It is not intended to substitute for the medical expertise and advice of your health care provider(s). We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy is not an endorsement by NCCIH.

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NCCIH Pub No.: 
Last Updated: 
March 2015

This page last modified September 24, 2017