Brain oxidative stress may be involved in a number of diseases and aging. Coenzyme QIO is the only known lipid soluble endogenous antioxidant that animal cells can synthesize "de novo" and for which there exist enzymatic mechanisms that can regenerate the antioxidant from its oxidized form resulting from its inhibitory effect of lipidperoxidation. Synthetic CoQ10 given to patients with benign essential hypertension has a neuropsychopharmacological effect similar to a "cognitive enhancer" (bioequivalency concept) documented by Quantified Pharmaco EEG™ (QPEEG). This neuropsychopharmacological effect may play an important future role in treating or preventing cerebral oxidative damage in vascular and other conditions such as those observed in benign essential hypertension and other pathological brain conditions as well as in physiologic aging.