Active Form of CoQ10 - 50 mg Superior Bioavailability Ubiquinol is the reduced and active free radical quencher form of Coenzyme Q10 (CoQ10). CoQ10 is found in all cells of the body, with especially high concentrations in the heart. It is essential to mitochondrial energy production and functions as a powerful, fat soluble, free radical scavenger. These properties make Ubiquinol an ideal supplement for the support of energy production and free radical protection in the heart, vascular structures, brain and neurons. NOW Ubiquinol CoQH-CF features D-Limonene to naturally enhance its solubility and intestinal absorption, to create a product with superior biological value.