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

The bioavailability of the reduced form of coenzyme Q10 (ubiquinol) was compared to oxidized coenzyme Q10 (ubiquinone) with identical soft gel capsule excipients by measuring steady state plasma coenzyme Q10 (CoQ10 ) levels in 12 healthy volunteers. After baseline levels of ubiquinol, ubiquinone, total CoQ10 , 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 CoQ10 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 CoQ10 /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 CoQ10 and the increase in CoQ10 /cholesterol ratio were significantly better after ubiquinol (P < 0.005 and P < 0.001, respectively) than after ubiquinone indicating superior bioavailability. Plasma ubiquinol/total CoQ10 ratio increased from baseline during ubiquinol supplementation (P < 0.005) and remained unchanged after ubiquinone supplementation. No side effects were noted in this study.