The purpose of this study is to find out whether ubiquinol is well tolerated, can affect the symptoms of Parkinson's Disease and change the energy levels in the brain. Subjects will be randomized to taking ubiquinol or placebo and will have a neurological evaluation, magnetic resonance spectroscopy (MRS) and blood test for biological markers taken during the study.

Multiple lines of evidence have implicated abnormal energy metabolism and deficient mitochondrial function in Parkinson's disease, presenting a unique target for therapy. A pilot study of ubiquinol in PD was therefore undertaken to determine its effects upon physiologic measures of mitochondrial metabolic function. The incorporation of a neuroimaging biomarker is particularly important, since changes would demonstrate our ability to achieve Central Nervous System (CNS) access from this an formulation, accompanied by a meaningful neurophysiologic effect. Hydrogen Proton Magnetic Resonance Spectroscopy Imaging (1H MRSI) is a technique that provides insight into the metabolism of several endogenous brain compounds, most notably N-acetyl-L-aspartate (NAA), choline-containing compounds (Cho), and creatine and phosphocreatine (Cr). A number of studies of mitochondrial function have now firmly established the utility of 1H MRSI in probing potential mitochondrial energy metabolism dysfunction, in primary mitochondrial disorders, but also in PD. This pilot study is therefore designed to test whether oral ubiquinol affects cerebral indices of mitochondrial dysfunction, as measured by 1H MRSI in patients with Parkinson's disease, and to gather preliminary information on the safety and tolerability of ubiquinol in individuals with PD.

Inclusion Criteria:

• diagnosis of PD according to the Untied Kingdom (UK) Brain Bank Criteria, and confirmed by a Movement Disorders neurologist;
• age 40-75 years; diagnosis within 5 years of study participation;
• PD medications able to remain at stable doses in the opinion of the enrolling investigator;
• able to undergo MRI;
• absence of significant medical, psychiatric, and other neurological disease;
• absence of dementia and Mini-Mental State Examination (MMSE) > 26.

Exclusion Criteria:

• failure to meet diagnosis by above criteria;
• time since diagnosis > 5 years before study participation;
• PD medications not predicted to remain at stable doses in the opinion of the enrolling investigator;
• unable to undergo MRI;
• unable to comply with informed consent process;
• presence of significant medical, psychiatric (including major depressive disorder) or other neurological (including epilepsy, brain tumor, stroke) disease;
• diagnosis of dementia and/or MMSE 26 or lower;
• possibility of pregnancy (negative test required in women of childbearing age);
• taking medications including antipsychotic agents and dopamine- blocking anti-emetic agents;
• taking Coenzyme Q10;
• participation in another clinical trial within the last 3 months.