Safety and side effects

CoQ10 supplements appear to be safe and to produce few side effects when taken as directed.

Mild side effects might include:

  • Upper abdominal pain
  • Loss of appetite
  • Nausea
  • Diarrhea
  • Headaches
  • Insomnia
  • Rashes
  • Fatigue
  • Dizziness
  • Light sensitivity
  • Irritability

The safety of use of CoQ10 during pregnancy and breast-feeding hasn't been established. Don't use CoQ10 if you're pregnant or breast-feeding.

Interactions

Possible interactions include:

  • Anticoagulants. CoQ10 might make blood-thinning drugs, such as warfarin (Coumadin, Jantoven), less effective. This could increase the risk of a blood clot.
  • Oct. 13, 2017