Ubiquinol or plain CoQ10? In a five-way trial of shop-shelf capsules, both lifted blood levels, the gap between them was too small to be sure of, and no one felt more energetic

Coenzyme Q10 sits in every cell, helping mitochondria turn food into usable energy and mopping up some of the oxidative damage along the way. The body makes its own, but CoQ10 is also one of the best-selling supplements, and the shelf offers a choice. There is ubiquinone, the oxidised form that has been sold for decades, and ubiquinol, the reduced form, usually more expensive and marketed as easier to absorb. More recently, geranylgeraniol, a compound extracted from annatto seeds, has been sold to help the body build more CoQ10 itself. A trial published in the Journal of Nutrition and Metabolism on 27 September 2026 put all of them side by side.

Researchers led from the University of Maryland School of Medicine recruited 150 adults aged 40 or over at clinics across the United States between October 2024 and June 2025. Their average age was 52, three in four were women, and nobody had taken a statin in the previous six months. Each was randomly given one of five bottles that looked the same from the outside: 200 mg of ubiquinone, 200 mg of ubiquinol, 300 mg of geranylgeraniol, a capsule with 200 mg of ubiquinol and 120 mg of geranylgeraniol, or a placebo. These were ordinary products bought off the shelf, taken at the label dose of one capsule a day with a meal for eight weeks.

At the start, everyone's blood CoQ10 sat a little under 1 mg per litre. Eight weeks later it had risen to about 2.4 on ubiquinone, 3.2 on ubiquinol and 3.4 on the ubiquinol and geranylgeraniol combination, while the placebo group stayed put. Ubiquinol came out ahead of ubiquinone on average, but the difference was not statistically significant, so the trial can't say one form is better. The combination edged out plain ubiquinone by about 1 mg per litre, though only just past the significance line. Geranylgeraniol on its own didn't move CoQ10 at all. Cholesterol and liver tests didn't change, and questionnaires on energy, vigour and overall physical and mental health showed no difference from placebo in any group.

A few cautions. The volunteers were healthy, so a higher CoQ10 number in the blood is all the trial measured; it says nothing about whether anyone's health improved. The ubiquinone was a dry powder capsule while the ubiquinol products were oil-filled softgels, and the capsules weren't disguised, so participants could in principle have noticed differences. A small signal of better kidney numbers in the geranylgeraniol groups was not adjusted for the many tests run, and the authors call it hypothesis-generating. And the study was paid for in full by Designs for Health, the company that sells both geranylgeraniol products tested; the lead author sits on its scientific advisory board, though the paper states the company had no role in the design, analysis or writing.