Health Reference LibraryUbiquinol vs ubiquinone: which form of CoQ10 should you choose?
This entry is part of the Nutri Tailor Health Reference Library — cited research on supplements, nutrients and adjacent areas of health.
Summary
Ubiquinone and ubiquinol are the oxidised and reduced states of the same molecule, coenzyme Q10. The body converts between the two continuously, and pharmacokinetic work reports that CoQ10 taken by mouth appears in the blood in its reduced state regardless of which form was swallowed. Several small crossover studies report higher blood CoQ10 levels after ubiquinol, particularly in older adults, while other work finds the response varies between individuals and depends heavily on the formulation, such as whether the capsule is oil based. Most clinical research on CoQ10 has used ubiquinone. Ubiquinol products are typically more expensive, and no UK guideline recommends one form over the other.
How it works
Coenzyme Q10 is a fat soluble molecule present in almost every cell, where it carries electrons in the mitochondrial chain that produces cellular energy. In doing that job it cycles constantly between an oxidised state, called ubiquinone, and a reduced state, called ubiquinol. A 2008 crossover study of two formulations noted that orally taken CoQ10 appears in plasma with little change in its redox balance whichever form is swallowed, which the authors read as evidence of an efficient conversion mechanism in the body. The two names therefore describe states of one molecule rather than two different nutrients.
Effective dose
The crossover studies comparing the forms used single doses of around 100 milligrams or daily doses of 100 to 200 milligrams. Clinical trials of CoQ10 more broadly have used a wide range, commonly 100 to 300 milligrams per day. No UK guideline sets a dose for either form. For supplements sold in the UK, the label dose on the product is the reference point.
Forms compared
Ubiquinone is the standard supplemental form, is stable in manufacturing, and is often labelled simply as coenzyme Q10 or CoQ10. Ubiquinol is chemically less stable, which a 2023 review identifies as the manufacturing challenge behind newer stabilised formulations. Products containing ubiquinol are labelled as such and usually cost more. Absorption research reports that the carrier matters for both forms, with oil based soft gel formulations generally outperforming dry powder capsules for this fat soluble molecule.
Timing
CoQ10 is fat soluble, and absorption research reports better uptake when it is taken with a meal that contains some fat. The 2008 crossover study administered the supplement with oil for that reason. No evidence reviewed here supports a particular time of day.
Safety profile
Both forms are reported as well tolerated in the trials reviewed, including a phase 2 trial that used high dose ubiquinol and reported it as well tolerated. Mild digestive upset is the commonly reported effect at higher doses in the wider CoQ10 literature. Anyone taking CoQ10 alongside prescriptions should raise it with a GP or pharmacist.
Special populations
Reviews report that the conversion from ubiquinone to ubiquinol appears to become less efficient with age, and the crossover studies showing the clearest advantage for ubiquinol were conducted in older adults. A single dose study in adults over 60 reported a several fold higher plasma exposure with ubiquinol, and a two week study in older men reported higher plasma CoQ10 after ubiquinol at the same daily dose. These are small studies, and the 2025 crossover work found the advantage present in roughly six of ten participants rather than universally.
Interactions
Statin prescriptions, which lower cholesterol, are reported in the CoQ10 literature to lower blood CoQ10 levels as a side effect of the same pathway. Questions about taking CoQ10 alongside statins or any other prescription belong with a GP or pharmacist rather than with a supplement page. Nutri365 checks for interactions and contraindications when reading a plan.
Guideline positions
No NHS or NICE guidance recommends CoQ10 supplementation for the general population, and none takes a position on the choice between ubiquinone and ubiquinol. The evidence on the comparison consists of small pharmacokinetic and crossover studies plus manufacturer sponsored formulation work, which is worth knowing when weighing the claims made for either form.
Practical framework
The comparison narrows to three practical points. The two forms interconvert in the body, so the choice concerns absorption rather than function. The absorption advantage reported for ubiquinol is clearest in older adults and is not consistent across individuals, while formulation quality matters for both forms. Price differs, with ubiquinol typically costing more per milligram. Coenzyme Q10 capsules at 100 milligrams are available at nutritailor.co.uk/products/co-enzyme-q10-100mg. Nutri365 reads your results and history over time, checks for interactions and contraindications, and refers questions outside scope to a GP or a BANT registered nutritional therapist.
Common misconceptions
Ubiquinol is sometimes described as a different and newer nutrient, but it is the reduced state of the same CoQ10 molecule. It is also sometimes claimed that ubiquinone does not work, yet most of the clinical CoQ10 evidence was produced with ubiquinone, and pharmacokinetic work shows the body converts it to ubiquinol after absorption. A third misconception is that form is the main driver of absorption, whereas the comparative studies report that the formulation, such as an oil based soft gel against a dry capsule, matters at least as much as the redox form.
Forms compared
| Form | Redox State | Typical Label Wording | Evidence Base |
|---|---|---|---|
Sources
- Soni K et al. 2026. A Randomized, Double-Blind, Two-Treatment, Two-Period, Crossover Study Investigating the Systemic Bioavailability of a Novel Cocrystal Ubiquinol Formulation Compared with a Ubiquinone Formulation in Healthy Adults. Clinical Pharmacology in Drug Development, DOI 10.1002/cpdd.70042.
- Evans M et al. 2009. A randomized, double-blind trial on the bioavailability of two CoQ10 formulations. Journal of Functional Foods.
- review (PMC10610044) 2023. The Cocrystal of Ubiquinol: Improved Stability and Bioavailability. Molecules (PMC).
- registered trial NCT03020680 (Zhang et al.) 2018. Bioavailability of Ubiquinone and Ubiquinol in Older Adults. ClinicalTrials.gov.