Comparison study of plasma coenzyme Q10 levels in healthy subjects supplemented with ubiquinol versus ubiquinone

Abstract The bioavailability of the reduced form of coenzyme Q 10 (ubiquinol) was compared to oxidized coenzyme Q 10 (ubiquinone) with identical soft gel capsule excipients by measuring steady state plasma coenzyme Q 10 (CoQ 10 ) levels in 12 healthy volunteers. After baseline levels of ubiquinol, ubiquinone, total CoQ 10 , α‐tocopherol, and total cholesterol were obtained, follow‐up lab work was performed after 4 weeks of 200 mg/day of ubiquinone, after 4 weeks washout, and after 4 weeks of 200 mg/day of ubiquinol. Plasma total CoQ 10 increased from 0.9 to 2.5 µg/mL ( P < 0.001) after 4 weeks of ubiquinone and increased from 0.9 to 4.3 µg/mL ( P < 0.001) after 4 weeks of ubiquinol. Total CoQ 10 /cholesterol ratio increased from 0.2 to 0.7 µmol/mmol after 4 weeks of ubiquinone and increased from 0.2 to 1.2 µmol/mmol after 4 weeks of ubiquinol. Both the increase in plasma CoQ 10 and the increase in CoQ 10 /cholesterol ratio were significantly better after ubiquinol ( P < 0.005 and P < 0.001, respectively) than after ubiquinone indicating superior bioavailability. Plasma ubiquinol/total CoQ 10 ratio increased from baseline during ubiquinol supplementation ( P < 0.005) and remained unchanged after ubiquinone supplementation. No side effects were noted in this study.