Coenzyme Q10 (CoQ10) is a quinone that is found throughout the human body in cell membranes, primarily in mitochondrial membranes, with the highest levels in the heart, lungs, liver, kidneys, spleen, pancreas, and adrenal glands.¹ It exists in three redox states: fully oxidized (CoQ10/ubiquinone), partially reduced (semiquinone or ubisemiquinone), and fully reduced (ubiquinol).² CoQ10 acts as an electron shuttle in the electron transport chain via its reduction to ubiquinol between mitochondrial complexes I and II, also known as NADH dehydrogenase and succinate dehydrogenase, respectively, and mitochondrial complex III, also known as cytochrome bc1 complex.^3,4 CoQ10 is also reduced to ubiquinol by ferroptosis suppressor protein 1 (FSP1) with NADPH as a cofactor, and ubiquinol traps lipid peroxyl radicals and inhibits lipid peroxidation helping to prevent ferroptosis.⁵ Mutations in genes encoding enzymes involved in CoQ10 biosynthesis lead to primary CoQ10 deficiency, which is characterized by encephalopathy, cerebellar ataxia, infantile multisystemic form, nephropathy, and isolated myopathy.⁶ Secondary CoQ10 deficiency, induced by non-genetic impaired CoQ10 biosynthesis, insufficient CoQ10 intake, or excessive CoQ10 utilization, has been observed in a variety of conditions, including ataxia-oculomotor-apraxia 1 (AOA1), mitochondrial diseases, and hypercholesteremia with statin therapy.^7,8 Formulations containing CoQ10 have been used in the treatment of CoQ10 deficiency.