Coenzyme Q10 → Major cardiovascular events
Higher Coenzyme Q10 decreases Major cardiovascular events.
Mortensen 2015 found that 100 mg of coenzyme Q10 three times a day for two years halved a first major heart-failure event versus placebo in 420 people (15 percent versus 26 percent; hazard ratio 0.50). Morisco 1994 had already cut hospitalizations for worsening failure in 641 people on 2 mg per kg a day.
Randomized trial · Contested · N=641
Supported by an experiment or a tightly identified design. Read the caveats.
Mechanism
Authors treat coenzyme Q10 as a mitochondrial cofactor that is low in failing heart muscle. They do not isolate one downstream path. Mortensen, Rosenfeldt, Kumar and colleagues assigned 420 people with moderate to severe heart failure to 100 mg three times a day or placebo for two years on top of standard therapy (Q-SYMBIO). Short-term NYHA class, six-minute walk, and NT-proBNP did not change at 16 weeks. By two years, a first major adverse cardiovascular event had occurred in 15 percent versus 26 percent (HR 0.50, 0.32 to 0.80, P=0.003). Cardiovascular death was 9 percent versus 16 percent. All-cause death was 10 percent versus 18 percent. NYHA class improved at two years. Mortensen, Rosenfeldt and Filipiak re-analyzed the European subgroup. Major events were 9 percent versus 27 percent (P=0.001). Ejection fraction also moved in that slice. Same assignment. Morisco, Trimarco and Condorelli (1994) assigned 641 people with NYHA class III or IV failure to 2 mg per kg a day or placebo for one year. Hospitalization for worsening failure was 73 versus 118. Pulmonary edema episodes were 20 versus 51. Cardiac asthma episodes were 97 versus 198.
Caveats
Researchers assigned people to a capsule or a control, so this is a trial stamp. These are heart-failure trials, not a general-population event trial. More papers of the same design do not settle the claim. Short-term Q-SYMBIO endpoints missed. The two-year win is events and later NYHA. The European paper is the same randomization, not a second trial. Morisco counts hospitalizations and acute failure episodes, not a modern MACE composite. This is a journal entry, not medical advice and not a reason to take coenzyme Q10 after a heart diagnosis.
Effect
odds_ratio = 0.5. Mortensen 2015 Q-SYMBIO: 100 mg TID, 2 y, N=420 HF. MACE 15% vs 26%, HR 0.50. Morisco 1994: 2 mg/kg/d, 1 y, N=641. Hospitalized 73 vs 118.
Nodes
Named confounders
Cite this page
What Causes What. “Coenzyme Q10 → Major cardiovascular events.” https://whatcauseswhat.org/edges/e-q10-cv (atlas updated 2026-09-02).
Papers
- The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial.
SA Mortensen, F Rosenfeldt, A Kumar, P Dolliner, KJ Filipiak, D Pella, U Alehagen, G Steurer · 2015 · JACC. Heart failure
- Effect of coenzyme Q10 in Europeans with chronic heart failure: A sub-group analysis of the Q-SYMBIO randomized double-blind trial.
AL Mortensen, F Rosenfeldt, KJ Filipiak · 2020 · Cardiology journal
- Effect of coenzyme Q10 therapy in patients with congestive heart failure: a long-term multicenter randomized study.
C Morisco, B Trimarco, M Condorelli · 1994 · The Clinical investigator