The Mito-Frail Trial: Effects of MitoQ on Vasodilation, Mobility and Cognitive Performance in Frail Older Adults

The goal of this clinical trial is to test the effects of MitoQ supplementation in older adults and frail older adults with physical dysfunction and/or cognitive dysfunction. The main question\[s\] it aims to answer are: * To compare vascular function, oxidative stress levels, and physical and cognitive function among older adults and frail older adults with physical and cognitive dysfunction * To determine whether MitoQ supplementation has the potential to improve vascular function in central and cerebral vessels * To determine whether MitoQ supplementation can enhance physical and cognitive capabilities.

Inclusion Criteria: * men and women aged 65-80 with a slow gait speed (0.4m/s based on a 4m walk) and/or mild cognitive impairment. * good cardiovascular health (not taking any blood pressure/flow/metabolism altering medications) Exclusion Criteria: * A vaccination in past two weeks * Recent acute infection three weeks prior to enrollment * Known immunodeficiency (including HIV infection, primary immunodeficiency, any history of chemotherapy or radiotherapy * Use of medicines during past 6 months known to alter immune response such as high- dose corticosteroids * Severe autoimmune disease requiring biological therapy * Major severe illness and/or Hospitalization in past 3 months * On warfarin or other medications that are considered a blood thinner * Recent fall or other conditions that will impair ability to complete and/or interpret mobility performance test * Known bleeding disorder * Any conditions that would impair the function to perform grip strength test * include advanced neurological disease, severe co-morbid disease, terminal illness with reduced life expectancy, severe disability, unintentional weight loss in last 12 months and participation in another study. * Diabetes patients requiring insulin (For reducing the risk that participants will have hypoglycemic episodes when fasting for study visits) * Baseline ECG QTc \>450 ms in men and QTc \>460 ms in women * Prior diagnosis of ventricular arrhythmia (e.g., ventricular tachycardia, ventricular fibrillation, torsades de pointes)