Ubiquinol

If you take CoQ10, ordinary ubiquinone taken with a meal containing fat is a sound default. Ubiquinol is not wrong, but the evidence does not justify its price, and branded "high-absorption" versions have no outcome data at all.

What it is

CoQ10 is a fat-soluble molecule the body makes itself and also gets from food. In mitochondria, the cell's power plants, it carries electrons in the chain of reactions that produces adenosine triphosphate (ATP), the cell's main energy currency. To do that it cycles between two forms: an oxidized form, ubiquinone, and a reduced, electron-rich form, ubiquinol. In the ubiquinol state it also neutralises reactive oxygen molecules, protects fats in cell membranes from oxidation, and regenerates the active forms of vitamins E and C.^[1]

Both forms are sold as supplements. The two forms are continually converted into each other inside cells, so the main marketing question is which one gets more CoQ10 into the blood.^[2]

Does it absorb better?

Conventional crystalline CoQ10 is poorly absorbed, because it is large, fat-loving and barely water-soluble, and absorption varies widely from person to person.

• The review evidence is disputed. Whether ubiquinol absorbs better depends heavily on the formulation — for example, whether the CoQ10 crystals were broken up by heat treatment during manufacture — so neither form is clearly better, according to a review by authors working for a ubiquinone maker.^[3]
• A head-to-head trial found a small, non-significant gap. In a 2026 five-arm trial in 150 healthy adults (average age 52; about 30 per group), 200 mg a day of ubiquinol raised blood CoQ10 somewhat more than ordinary ubiquinone over eight weeks, but the gap was small and not statistically significant, and neither form made people feel more energetic than placebo.^[4]
• Newer formulations claim bigger gains. A small 2026 crossover trial of a cocrystal ubiquinol in 12 fasting healthy adults reported roughly two- to three-fold higher blood exposure than a standard ubiquinone reference,^[5] and one manufacturer-run, open-label crossover study of a liposomal powder in healthy volunteers reported about four-fold higher exposure than conventional CoQ10.^[6] These are small, industry-run studies of blood levels.

Higher blood levels are not the same as clinical benefit, and they do not mean more CoQ10 reaches the brain, which the blood–brain barrier largely excludes. Formulation (softgel versus dry powder) and taking it with fat may matter as much as which form you buy. The one robust rule is that CoQ10 is absorbed better when taken with a meal that contains fat.^[7]

The trials that mattered used ubiquinone

The two trials that moved a hard endpoint for CoQ10 — Q-SYMBIO in heart failure and KiSel-10 in older Swedes — both used plain ubiquinone. That undercuts the marketing claim that the reduced form is decisively superior. One trial that did use ubiquinol, at 1,500 mg a day, was in a rare brain disease linked to a CoQ10-building gene (see Primary CoQ10 deficiency).

The "redox" argument, and why it is untested

A German study of 1,333 adults, followed for a median of about 13 years, found that people with a larger share of their blood CoQ10 in the oxidized ubiquinone form were more likely to die: about 18% higher risk per standard-deviation increase (hazard ratio 1.18, 95% confidence interval 1.02–1.36), and nearly double comparing the most-oxidized third to the least (1.92, 95% confidence interval 1.16–3.17). The confidence interval is the range where the true effect most plausibly lies; both stay above 1.0, the value meaning no difference, so the increase is unlikely to be chance alone. This study measured CoQ10 in the blood, not supplement use.^[8]

From findings like this comes an idea that CoQ10 helps only if the body can keep it in the ubiquinol form, and that under heavy oxidative stress, as in obesity, it cannot. The groundwork is thin: lower CoQ10 levels have been reported in obesity in animals and people, but most of that research is in animals, according to a review by authors working with a CoQ10 maker.^[9] Whether switching to ubiquinol helps people with poor redox capacity has never been tested.

What to do

1. Buy plain ubiquinone unless you have a specific reason not to. It is what the outcome trials used.
2. Take it with a meal that contains fat — this is the one absorption step with consistent support.
3. Ignore "x-fold absorption" claims for branded delivery systems until outcome data exist; they come from small, maker-run blood-level studies.

Further reading

• Mantle D et al. Bioavailability of Coenzyme Q10: An Overview of the Absorption Process and Subsequent Metabolism. Antioxidants (Basel) 2020.^[10]
• D'Adamo CR et al. A Randomized, Double-Blind, Placebo-Controlled Trial Comparing the Effects of Commercially Available Ubiquinone, Ubiquinol, and Geranylgeraniol Dietary Supplements on Plasma CoQ10 Concentrations. J Nutr Metab 2026.^[11]
• Mei X et al. 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. Clin Pharmacol Drug Dev 2026.^[12]
• Stürmer P et al. Higher Redox State of Coenzyme Q10 Is Associated with Higher Risk of All-Cause Mortality in a Sample from the Northern German General Population. Antioxidants 2026.^[13]
• Bentinger M et al. The antioxidant role of coenzyme Q. Mitochondrion 2007.^[14]