Evidence Level
Moderate
CoQ10 has one of the strongest evidence bases of any supplement for cardiovascular health, anchored by the Q-SYMBIO trial showing remarkable mortality reduction in heart failure. Its role in the electron transport chain is biochemically essential — without CoQ10, cells cannot produce ATP aerobically. For exercise performance in young, healthy athletes, benefits are modest and inconsistent, likely because CoQ10 levels are already adequate. The supplement becomes more relevant with aging (CoQ10 levels peak around age 20 and decline), statin use (which depletes CoQ10), and in individuals with mitochondrial dysfunction. Ubiquinol is the preferred supplemental form due to 3-6x better bioavailability.