Coenzyme Q10, also known as CoQ10, is a popular antioxidant recommended for a variety of conditions from infertility to heart conditions to migraines. Fun fact: CoQ10 is not a vitamin! It’s a nutrient that exists in almost every cell of the human body. In your body, CoQ10 shifts back and forth between two states in a continuous cycle: ubiquinone and ubiquinol. CoQ10 supplements on the market will be one of these two forms.
What’s the difference between ubiquinol and ubiquinone?
Both ubiquinol and ubiquinone are true forms of CoQ10, and the terms are often used interchangeably. From a chemistry standpoint, ubiquinol is the reduced form of CoQ10, whereas ubiquinone is the oxidized form.
Remember that CoQ10 occurs naturally in the body, where it shifts between its ubiquinone and ubiquinol form in a continuous cycle. When you take a ubiquinone supplement, your body converts it to ubiquinol and back again. So regardless of what form of CoQ10 you take, your body will convert it to the other form as needed.
Ubiquinone was the only version of CoQ10 on the market until 2007, when the developer of the patented technology for producing the active form of CoQ10 commercialized (and trademarked) ubiquinol. Because of this, ubiquinol is more expensive. Some people assume that because it’s more expensive, it is better. But there’s no compelling data to support that claim.
Ubiquinol and ubiquinone: is one better than the other?
Research has not proven one form of CoQ10 is better than the other, and given the body naturally converts between the two forms, it is unlikely that there is a big difference between them.
It is important to note that ubiquinone has been on the market longer and has been used in the vast majority of clinical trials of CoQ10 (including those studying the benefits of CoQ10 for fertility).
Both forms of CoQ10—ubiquinol and ubiquinone—are considered safe, with few side effects.
Which form of CoQ10 is more bioavailable?
The bioavailability of a supplement is the proportion which reaches systemic circulation and can be used by the body. Both ubiquinone and ubiquinol have high bioavailability.
One study found no significant difference in the absorption of various CoQ10 formulations and that CoQ10 appeared in the blood as ubiquinol, even if it was consumed as ubiquinone. Another study of seven different supplement formulations found large differences in the bioavailability of formulations, with the best absorbable formulations being soft-gel capsules containing either ubiquinone or ubiquinol.