Who should not use CoQ10?


Coenzyme Q10 (CoQ10) is a popular antioxidant supplement taken for heart health, brain function, exercise performance and more. It is generally well-tolerated, even at high doses. However, there are some situations where caution is warranted with CoQ10 use. In this comprehensive article, we’ll provide an evidence-based overview of contraindications and precautions for CoQ10 supplementation.

Who should not use CoQ10?

What is CoQ10?

First, some background on what CoQ10 is and why it’s used:

  • CoQ10 is a compound made naturally in the body that acts as an antioxidant and plays a vital role in cellular energy production.
  • Food sources include meat, fish, nuts, seeds, broccoli, spinach. Levels can decline with age or use of statin medications.
  • CoQ10 supplements may provide benefits for heart failure, high blood pressure, Parkinson’s disease, migraines, exercise performance, fertility, and more.
  • Typical doses range from 100-300 mg per day. Up to 3000 mg daily is well-tolerated in research studies. Adverse effects are mild and uncommon.
  • CoQ10 exists in an oxidized form called ubiquinone and reduced form called ubiquinol. The latter may have better bioavailability.

Situations Where Caution is Warranted with CoQ10

While generally safe for most people, some situations where caution or medical guidance is prudent with CoQ10 include:

Pregnancy and Breastfeeding

  • Impact of CoQ10 supplementation has not been studied adequately in pregnant or breastfeeding women.
  • Given lack of data, high supplemental doses are not recommended as a precaution during pregnancy.
  • No adverse events have been reported either, so CoQ10 is likely low risk but benefits vs potential risks should be considered.

Children and Adolescents

  • There is insufficient research on safe or effective dosing of CoQ10 in children or teenagers.
  • Require medical guidance before giving any supplements, including CoQ10. Avoid unauthorized high doses.
  • CoQ10 synthesis peaks around age 20 so supplementation is likely not necessary in healthy young people unless deficiency is confirmed.

Sensitivities and Allergies

  • CoQ10 supplements are contraindicated in anyone with a known allergy or hypersensitivity to CoQ10 or related compounds.
  • Allergic reactions may include rash, itching, swelling, trouble breathing, chest pain. Seek medical care immediately if these occur.
  • Use caution when introducing CoQ10 the first time in anyone with tendencies for allergies or sensitivities.

Surgery Soon

  • CoQ10 may interfere with blood pressure control during surgery. Discontinue at least 2 weeks before a scheduled surgery.
  • Inform your doctor about any supplements you take, including CoQ10, when planning for an operation.
  • CoQ10 may also affect blood glucose levels so diabetic patients need to monitor closely before surgery.

Organ Transplants

  • Persons who have received an organ transplant like a heart or kidney transplant should avoid CoQ10 supplementation unless under medical supervision.
  • Impact on anti-rejection immunosuppressant medications is unknown. Interactions are theoretically possible.
  • Anyone taking immunosuppressant drugs should discuss CoQ10 with the prescribing physician and transplant team for specific guidance.

Medical Conditions Warranting Caution with CoQ10

Those with certain health conditions should exercise caution or avoid CoQ10 supplementation unless monitored by a doctor:

  • Bleeding disorders - CoQ10 may inhibit platelet aggregation increasing risk of bleeding complications. Avoid use at least 2 weeks before any surgery as well.
  • Diabetes - CoQ10 may lower blood glucose levels. This requires close monitoring of medications and glucose levels by a doctor. Hypoglycemia is possible.
  • Hypertension - CoQ10 may reduce blood pressure in some individuals. Those on antihypertensive medications need blood pressure monitoring with CoQ10 use.
  • Thyroid disorders - CoQ10 supplementation may alter thyroid hormone levels in some cases. Requires thyroid monitoring and medical guidance.
  • Bipolar disorder - CoQ10 may have stimulant effects that could potentially worsen manic symptoms. Use only under psychiatric care in bipolar disorder.
  • Melanoma - Given antioxidant effects, CoQ10 may be contraindicated for those with a history of melanoma. Discuss with your oncologist.
  • Kidney disease - Impaired kidney function may require adjusting dosage of certain supplements like CoQ10. Seek medical guidance in kidney disease.
  • Liver disease - Liver helps regulate CoQ10 status so impaired liver function can complicate use of supplements. Monitor liver enzymes and symptoms.

Medication Interactions to Be Aware of with CoQ10

CoQ10 supplementation may potentially interact with some medications. Those taking the following drugs should consult their doctor before using CoQ10:

  • Anticoagulants and antiplatelets - Like warfarin, clopidogrel, heparin. CoQ10 may increase bleeding risk.
  • Chemotherapy drugs - CoQ10’s antioxidant effects may interfere with some chemotherapy agents. Ask your oncologist.
  • Diabetes medications - CoQ10 may lower blood sugar requiring adjustment of diabetes drugs. Monitor glucose closely.
  • Thyroid medications - CoQ10 may alter thyroid hormone levels. Requires monitoring thyroid labwork.
  • Blood pressure lowering drugs - CoQ10 can also reduce BP. Dose adjustment possibly needed for medications.
  • Immunosuppressants - Those taking after organ transplant. Unclear if CoQ10 alters effects of these drugs.
  • Statins - Cholesterol medications like atorvastatin that deplete CoQ10 levels. CoQ10 may improve statin side effects.

General Precautions for Safe Use of CoQ10

In addition to the specific situations above, some other general precautions for safe use of CoQ10 include:

  • Start with low doses like 100 mg daily and increase slowly over weeks. Monitor for any side effects.
  • Drink plenty of water to stay well hydrated. Supplements like CoQ10 require adequate fluids.
  • Avoid taking CoQ10 on an empty stomach to minimize risk of nausea or indigestion. Take with food.
  • Look for quality tested brands. Supplements lack FDA regulation so purchase from reputable manufacturers.
  • Tell your doctor about any supplements you take. Share dosages and the reasons for supplementation. Report any side effects.
  • Store CoQ10 supplements properly in cool, dry place. Protect from heat and moisture to avoid degradation.
  • Discontinue use if you experience signs of allergy, worsening medical symptoms, severe fatigue, or muscle pain. Seek medical advice promptly in those scenarios.

Who Can Safely Take CoQ10?

For the majority of the population, CoQ10 supplements appear safe when taken as recommended on labels and guided by the following parameters:

✓ Healthy adults without contraindications – Safe for most people over 18 unless allergy/sensitivity. Start with 100-200 mg doses.

✓ Seniors over 50 – Endogenous CoQ10 declines with age so supplementation benefits many seniors without medical conditions.

✓ Ongoing monitoring by doctor – Those with chronic illnesses like heart failure or Parkinson’s can use CoQ10 under medical supervision.

✓ Inform doctor of use – Even with common medications like statins, discuss CoQ10 use with your physician.

✓ Report side effects – Discontinue if any worrying symptoms arise and seek medical advice. Otherwise CoQ10 is well-tolerated.

✓ Buy quality brands – Reputable manufacturers follow proper protocols to ensure purity and potency.


In summary, while CoQ10 supplementation appears to be well-tolerated and have a low risk of side effects in most users, there are some situations where caution is warranted and medical guidance should be sought.These include use in children, pregnancy, before surgery, with immune conditions, kidney disorders, diabetes, and use alongside certain medications. Maintaining an open dialogue with your physician about supplement use is important. But for the majority of otherwise healthy adults, CoQ10 is generally considered very safe when used responsibly. More human research is still needed to identify potential contraindications for specific populations and medications.


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