CoQ10 Side Effects

Adverse Effects of Vitamin Q10

Due to its popularity and effectiveness as a nutritional supplement, CoQ10 has come under significant scrutiny as to its safety and toxicity (i.e., what are CoQ10's side effects). Currently, no large amounts of CoQ10 research have consistently shown that there are health risks associated with taking CoQ10. There are no serious health risks associated with taking CoQ10 in any amount.

CoQ10 Toxicity

Many vitamins (like Vitamin Q10) have associated levels of toxicity - or levels at which taking the vitamin can be poisonous. Currently, there is no known toxicity level for CoQ10.

Reported Side Effects of CoQ10

CoQ10 Research has shown that there are no serious side effects associated with taking CoQ10. However, minor CoQ10 side effects have been reported, including insomnia, dizziness. One cardiovascular study has reported rashes, nausea, and abdominal pain in a small number of subjects taking 300 mg of CoQ10 per day. No other studies have been done to corroborate this evidence. A more typical dosage of CoQ10 is 100 mg or less, so most people supplementing their diets with CoQ10 don't need to worry about this.

CoQ10 and Ancillary Prescription Drugs

As with most nutrients, CoQ10 reacts to particular drugs. Since CoQ10 is present in most cells in the human body, CoQ10 doesn't react in any serious way to any prescription drug - or the drug wouldn't pass FDA standards. However, certain drugs have been shown to affect the way or efficiency with which CoQ10 works in the body.

Oral agents that lower blood sugar such as glyburide and lipid-lowering drugs such as gemfibrozil and statins (lovastatin, pravastatin, and simvastatin) limit the effectiveness of CoQ10. This class of drugs cause a reduction in serum levels of CoQ10, resulting in this limitation.

Beta-blockers, or drugs that slow the heart rate and reduce blood pressure, work at slowing the CoQ10-assisted reactions. As we mentioned, CoQ10 is a "coenzyme" which means that it assists other enzymes in the body at completing its chemical tasks. Beta blockers, rather than reducing the effectiveness of CoQ10 itself, affect the processes and enzymes that it is CoQ10's responsibility to assist. This may be due to the fact that CoQ10 has been used in high blood pressure patients to increase the contractile force of the heart. By reducing the heart rate with drugs, you limit the need of CoQ10 to increase the heart's strength.

The one instance in which CoQ10 has been shown to decrease the effectiveness of a drug itself was the drug warfarin - an anticoagulant, or a blood thinner which prevents clotting. CoQ10 can reduce the effectiveness of this drug.