Introduction: Coenzyme Q 10 (CoQ 10 ) is a ubiquitous organic molecule with a significant role in the mitochondrial electron transport chain (ETC). As a result of its role in such an important biological process, CoQ10 deficiency has been implicated in the pathogenesis of numerous diseases such as Parkinson's disease (PD) and multiple sclerosis (MS). This has led to multiple attempts to use CoQ 10 supplementation as a treatment or pre-treatment with varying degrees of success. Areas covered: The present review will identify evidence of mitochondrial dysfunction in MS, PD and mitochondrial ETC disorders. In addition, the inability of Co 10 supplementation to elicit significant clinical outcome in these disorders and possible flaws in these studies will be discussed. The databases utilized for this review were the Web of science and PubMed, with inclusive dates . Expert opinion: A lack of improved neurological outcome in these disorders post treatment with CoQ 10 may be attributable to the limited ability of CoQ 10 to cross the blood-brain barrier. Thus, CoQ 10 alternatives should also be considered. Other factors including time of disease diagnosis, dosage, administration, and duration of CoQ 10 therapy may have a significant influence on the efficacy of this treatment.