Our endogenous Q10 production peaks and starts to decline in our early twenties, however, so many choose to take a supplement to compensate for the age-related loss. In a recent report, Austrian scientists specifically recommend one form of the compound called ubiquinone, arguing that is has the most exhaustive documentation.

Cardiovascular disease is the leading cause of death worldwide, according to WHO. Heart failure alone has been defined as a global pandemic that results in millions of deaths and impairs quality of life for sufferers of the condition. Recent studies have suggested that the vitamin-like compound coenzyme Q10 may offer useful nutritional support for people at risk of cardiovascular disease. However, the studies have not clearly distinguished between ubiquinone, the oxidized form of co-enzyme Q10, and ubiquinol, which is the reduced form of the compound. Apparently, there is a vital difference between the two. It is only ubiquinone that is backed by solid science, and this is the reason why this particular form of co-enzyme Q10 is what the Austrian researchers recommend in their new meta-analysis.

Ubiquinone is the best choice

Writing in the science journal Current Cardiology Reports, researchers from the University of Graz in Austria explain that they conducted a systematic PubMed search for randomized, double-blind, placebo-controlled, parallel, or cross-over studies of co-enzyme Q10, using the two search terms “ubiquinone” and “ubiquinol”. Out of 238 studies in total, they ended up with 28 eligible studies, which they carefully analyzed.

The main outcome of their analysis was as follows:

1) Test concentrations leading to cardiovascular benefits are much lower in ubiquinone studies than in studies where ubiquinol was used

2) Positive long-term effects are only observed in studies conducted with ubiquinone.

Two groundbreaking studies prove it

The scientists point to two specific trials in their meta-analysis, emphasizing them as hallmark studies in terms of reduced cardiovascular mortality. One is the Q-Symbio study that was published in Journal of the American College of Cardiology in 2014. Here, researchers showed that daily supplementation with 300 mg of ubiquinone lowered the heart-related mortality rate by 43 percent and the risk of MACE (major adverse cardiovascular events) by a similar number. The other study is KiSel-10, which was published in 2013 in International Journal of Cardiology. In this study, participants were randomly assigned to daily supplementation with either selenium yeast (200 micrograms) and ubiquinone (200 milligrams) or matching placebo. Both studies were conducted using a leading ubiquinone Q10 brand. This brand alone has been investigated in over 75 published double-blind, placebo-controlled studies, 26 of which are gold standard trials.

End of discussion?

In recent years, there has been a lot of discussion about ubiquinone and ubiquinol and which form is better, has superior absorption, and delivers the best effect. Both forms of co-enzyme Q10 are present in and used by the human body for different purposes, and the body can convert them back and forth, depending on its needs for one form or the other.

The fact is that the majority of research, not just with regard to cardiovascular disease but countless other health areas, has been conducted using the ubiquinone form of co-enzyme Q10. That is the bottom-line message of the current meta-analysis and the detail that people should pay attention to.

For decades, ubiquinone was the only form of coenzyme Q10 available in supplement form and was therefore the source, which researchers used in scientific trials. At one point, ubiquinol (also called QH) entered the stage. Clever marketing has given ubiquinol that much commercial tailwind, some people now consider this form of coenzyme Q10 to be superior. If you look at the facts, however, it is a different story. Here are some details to help clarify matters:

Fact 1: Nearly all scientific studies have been conducted with CoQ10

As mentioned earlier, the vast majority of science studies published from the late 1950s up until now have been conducted with ubiquinone, not ubiquinol. In other words, the documented health benefits of coenzyme Q10 primarily apply to ubiquinone. Whether or not the ubiquinol form would be able to deliver a similar effect remains unknown. It would require an equal number of well-designed studies to make a fair comparison. So far, only ubiquinone can deliver convincing documentation.

Fact 2: Ubiquinone is chemically more stable than ubiquinol

Ubiquinone, as mentioned, is the oxidized form of ubiquinol. Oxidation is a natural process where a substance reacts chemically with oxygen, which then changes the properties of the given substance. Ubiquinol is vulnerable to oxidation and is easily converted into its oxidized state. In other words, unlike ubiquinone, encapsulated ubiquinol requires effective protection in order to retain its chemical form. Ubiquinol is white, whereas ubiquinone is yellowish. The easiest way to determine the oxidative state of the compound is to pierce a capsule and squeeze out its content. Random spot checks of ubiquinol preparations often show that their content is yellow. In other words, the ubiquinol has been converted into ubiquinone.

Fact 3: Ubiquinol gets absorbed as ubiquinone in the small intestine

Once ubiquinol reacts physically with oxygen or gastric acid and/or intestinal fluids, it is automatically converted into ubiquinone. In other words, ubiquinone is absorbed in the form of ubiquinone in the small intestine. The body is able to convert ubiquinone into ubiquinol and vice versa and does so depending on its specific need for the two forms. The thing to focus on is how well the product is absorbed in the digestion and enters the bloodstream.

To sum up things, there are several reasons why it makes better sense for consumers as well as scientists to choose ubiquinone instead of ubiquinol. First of all, the available research points to ubiquinone as the most obvious choice. Secondly, the body converts ubiquinol into ubiquinone, once ubiquinol gets into contact with body fluids. And finally, the ubiquinol form is far more expensive and technically challenging to manufacture and handle.


“Comparison of Coenzyme Q10 (Ubiquinone) and Reduced Coenzyme Q10 (Ubiquinol) as Supplement to Prevent Cardiovascular Disease and Reduce Cardiovascular Mortality”

Current Cardiology Reports (published online on November 16, 2023) https://doi.org/10.1007/s11886-023-01992-6