Coenzyme Q10 – Ubiquinone or Ubiquinol?


Scientists first discovered Coenzyme Q10 back in year 1957, which then followed by abundant of research. In 1978, a British scientist Peter Mitchell has mapped out exactly how it works inside the cell and get awarded the Nobel Prize for Chemistry. Until today, there are still many ongoing research about this nutrient regarding its importance in health improvement and maintenance.

Names of Coenzyme Q10

Coenzyme Q10, or known as CoQ10, is a lipid soluble nutrient-like component crucial in every living cell. It exists in both reduced and oxidized form, which can go by many different names and abbreviations. It can be found with different names, commonly include:


Oxidized Form
Reduced Form
Common Doubt: Ubiquinone or Ubiquinol?

Figure 1: Redox Process of CoQ10

Ubiquinone and Ubiquinol are the redox pairs that can easily converted in between the forms. Ubiquinol is the antioxidant circulating around the body; while Ubiquinone is in great demand during energy production in the mitochondria. Upon ingestion, the CoQ10 is absorbed in its oxidized form. This is because the reduced form is highly unstable and get oxidized when exposed to air or in the stomach. When flowing in the blood or lymph system, it will convert into reduced form to fight against free radicals and provide antioxidant protection. When present in the mitochondria (the site for energy generation), it has to be in the oxidized form to get involved in energy synthesis process.

The concern is: there are many CoQ10 supplements in the market, is the oxidized or reduced form better? Basically, it doesn’t cause much difference to consume either form, since the CoQ10 can interchange between the forms to suit body’s need. However, it takes much efforts for the manufacturer to maintain the reduced form of CoQ10 in capsule due to its instability. Even so, the reduced CoQ10 will change its form during digestion and absorption. On the other hand, taking oxidized CoQ10 provides stable absorption, and more affordable too!


1. Pharma Nord. The History of Coenzyme Q10 Research. Retrieved from: 

2. Judy WV et al. 2007. Coenzyme Q10 Facts or Fabrications. Retrieved from: