Coenzyme Q10 (CoQ10) is a nutrient that occurs naturally in the body. CoQ10 is also in many foods we eat. CoQ10 acts as an antioxidant, which protects cells from damage and plays an important part in the metabolism.
There is some evidence that adding more -- in the form of CoQ10 supplements -- may be beneficial. Increasing age and some medical conditions are associated with dropping levels of CoQ10.