Comparison study of plasma coenzyme Q10 levels in healthy subjects supplemented with ubiquinol versus ubiquinone.
Level 3 - non-randomized controlled study
Non-randomized fixed-sequence comparative crossover study
PubMed 27128225 · doi:10.1002/cpdd.73
What was done
In 12 healthy volunteers, steady-state bioavailability was compared between oxidized coenzyme Q10 (ubiquinone) and reduced coenzyme Q10 (ubiquinol) using identical soft gel capsule excipients. Participants underwent baseline testing, followed sequentially by 4 weeks of 200 mg/day ubiquinone, a 4-week washout period, and 4 weeks of 200 mg/day ubiquinol. Steady-state plasma ubiquinol, ubiquinone, total CoQ10, α-tocopherol, and total cholesterol were measured after each intervention.
What was found
Plasma total CoQ10 increased from a baseline of 0.9 µg/mL to 2.5 µg/mL after ubiquinone (P < 0.001) and to 4.3 µg/mL after ubiquinol (P < 0.001), showing a significantly greater increase with ubiquinol (P < 0.005). Total CoQ10/cholesterol ratio rose from 0.2 µmol/mmol at baseline to 0.7 µmol/mmol after ubiquinone and to 1.2 µmol/mmol after ubiquinol (P < 0.001 between treatments). The plasma ubiquinol/total CoQ10 ratio increased from baseline only during ubiquinol supplementation (P < 0.005) and remained unchanged with ubiquinone. No side effects were observed.
Why it matters
This study provides direct pharmacokinetic evidence in humans that oral ubiquinol achieves substantially higher plasma CoQ10 levels and increases the circulating reduced fraction compared to an equal dose of ubiquinone in identical formulation.
Limits
The sample size was very small (n = 12). The design used a fixed order (ubiquinone then ubiquinol) rather than a randomized crossover sequence. Clinical outcomes and tissue concentrations beyond plasma were not evaluated.
Cited by
- supports Ubiquinol possesses higher bioavailability compared to ubiquinone, the oxidized form of coenzyme Q10.