One reason have always been cautious about CoQ10 is that years ago, my next door colleague and a biochemist involved in geriatric medicine did some studies on CoQ10 (and also shark cartilage). The scary part of his result was that none of the OTC health food store supplements actually demonstrated any biological activity. So assume in this study, they did things to keep the enzyme active!
Of the 420 patients with severe heart failure from Europe, India, Malaysia and Australia in the study, those who took 100 milligrams of coenzyme Q10 three times a day along with their current medical therapy showed improvement in their heart failure symptoms, such as shortness of breath and fatigue.