Two beneficial forms of CoQ10, ubiquinone and ubiquinol, are continually recycled in the body. Ubiquinol acts as a powerful antioxidant in mitochondria and lipid membranes. Sufficient amounts of both forms are needed for efficient ATP production. Normally, ubiquinone is efficiently reduced to ubiquinol during absorption or shortly after entering the bloodstream. However, this ability declines with age and may be compromised in certain individuals. As ubiquinol can be directly utilized by the body, CoQH is a good alternative for those who may have difficulty converting ubiquinone to ubiquinol. Pure ubiquinol is solubilized in d-limonene oil and stabilized with natural emulsifying agents.