Ubiquinone and ubiquinol are the oxidized and reduced variants of the nutrient Coenzyme Q10, reports Meghan Lyons MS. Ubiquinol is produced by the addition of an electron to ubiquinone and vice versa. The human body maintains an equilibrium between these forms of the enzyme.
As of 2015, ubiquinol has been seen as a more effective version of ubiquinone, as it has more recently emerged as a supplement, according to Meghan Lyons MS. However, ubiquinone and ubiquinol are simply different forms of Coenzyme Q10, and are easily interconverted by the body. Both forms of the enzyme are required by the body, either to donate or receive electrons. Thus, ubiquinone and ubiquinol are both effective supplements because the body uses both and simply converts one to another, if necessary.
Coenzyme Q10 is a fat soluble nutrient, which is found in nearly every cell of the human body. It is more highly concentrated in organs that require large amounts of energy, such as the heart and muscles, as it is essential for energy production, reports Meghan Lyons MS. Coenzyme Q10 is specifically located within the mitochondria of these organs and works as part of the electron transport chain. Ubiquinone accepts electrons along the transport chain, becoming ubiquinol. This ubiquinol molecule then continues to pass along the electron down the chain, returning to its original state.