Coenzyme Q10 is a wellness supplement. Evidence rating: 3 out of 5. Verdict: Cochrane review of CoQ10 for statin-induced myalgia (Banach et al., 2015 meta-analysis of 6 RCTs, n=302) found a small reduction in subjective muscle pain symptoms but inconsistent effects on objective markers like creatine kinase. The Q-SYMBIO RCT (n=420, 100 mg three times daily, 2 years) reported reduced major adverse cardiac events in heart failure patients on top of standard care. Evidence for benefit in healthy adults, fatigue, or cognition is weak. Not effective for primary prevention in the general population. Recommended dose: 100–200 mg/day. Key benefits: May reduce subjective muscle pain in statin-treated patients (meta-analysis of 6 RCTs); Q-SYMBIO RCT: reduced major adverse cardiac events in chronic heart failure as adjunct to standard care; Endogenous synthesis falls with age and is reduced by statins — supplementation has clear biological rationale; Useful adjunct in mitochondrial disorders under specialist supervision; Generally very well tolerated, even at high doses (>1,000 mg/day in trials); Antioxidant in lipid membranes — regenerates vitamin E. Warnings: Not a substitute for prescribed statin therapy — discuss with GP before stopping any cardiac medication; Mild GI upset (nausea, diarrhoea) most commonly reported adverse effect; May reduce warfarin efficacy (structurally similar to vitamin K) — INR monitoring required; May modestly lower blood pressure and blood glucose — monitor if on antihypertensives or diabetes medication; No proven benefit for healthy adults seeking energy or anti-ageing effects; Quality varies — choose products with declared ubiquinone/ubiquinol form and reputable brands.