Coenzyme Q10 (Ubiquinone / Ubiquinol)

•RCT evidence— Q-SYMBIO heart-failure trial

What it is

CoQ10 (ubiquinone in oxidised form, ubiquinol in reduced) is an electron carrier in the mitochondrial inner membrane shuttling electrons from complex I/II to complex III. It also serves as a lipid-phase antioxidant.

Why supplementation matters

• Endogenous CoQ10 synthesis falls with age, especially after 40.
• Statins block HMG-CoA reductase — the rate-limiting enzyme for both cholesterol and CoQ10 synthesis — reducing tissue CoQ10 by ~20–40%.
• CoQ10 deficiency may contribute to statin-associated muscle symptoms (debated; SAMSON trial suggests nocebo dominates).

Evidence

• Heart failure: Q-SYMBIO (2014) showed 300 mg/day reduced major adverse cardiovascular events and mortality in moderate-severe HFrEF.
• Statin myopathy: mixed results, but reasonable trial to run in symptomatic patients before changing statin.
• Migraine: meta-analyses show modest preventive benefit.
• Female fertility / ovarian reserve: emerging trials show improvements in oocyte quality.
• Longevity / mortality: KiSel-10 (Sweden) reported reduced cardiovascular mortality with selenium + CoQ10 in elderly.

Form matters

Ubiquinol is the active form; in adults over ~40, the body’s ability to reduce ubiquinone to ubiquinol declines. Pay the premium for ubiquinol in older adults.

Related entries

Mitochondrial dysfunction, Statins, Heart failure.