Coenzyme Q10 is made by the body and carries electrons in the cell's energy machinery. It is sold as a supplement for heart health and energy. The evidence that matters most comes from one large trial in heart failure and from a set of smaller trials on statin muscle symptoms.
Q-SYMBIO: heart failure over two years
Q-SYMBIO randomized 420 people with moderate to severe chronic heart failure, in 17 centers, to 100 mg of CoQ10 three times a day or placebo, on top of standard therapy, for two years. There was no difference at 16 weeks. At two years, major cardiovascular events (the primary composite) occurred in 15% of the CoQ10 group and 26% of the placebo group (hazard ratio 0.50, 95% CI 0.32 to 0.80).
The secondary results
Cardiovascular deaths were 9% with CoQ10 and 16% with placebo, and all-cause deaths were 10% and 18%. Heart-failure hospital stays were lower and functional class improved at two years. These were secondary outcomes, so they are supportive but do not replace the primary result.
Statin muscle symptoms
A 2018 meta-analysis of 12 randomized trials (575 people) found that CoQ10 reduced muscle pain, weakness, cramps and tiredness compared with placebo in statin users. Creatine kinase, a blood marker of muscle damage, did not fall. A 2024 meta-analysis of seven trials found a significant reduction in symptoms in four and no change in three, so the picture is mixed.
Healthy adults
No outcome trial shows that CoQ10 supplements prevent heart disease or improve energy in healthy adults. The heart-failure trial is the strongest outcome evidence, and it tested a specific dose in a specific population.
What this does not say
- Q-SYMBIO tested heart-failure patients on a prescribed dose of 300 mg a day, not the capsules sold for general use.
- The primary endpoint was a combined measure of cardiovascular events; it is not a measure of death alone.
- One trial, and a mixed set of smaller trials, do not prove a general benefit.
How we use this
Our physicians consider CoQ10 in the context of your history, your medicines and your goals. For people taking statins with muscle symptoms, the trials above are part of the discussion, alongside other causes that need checking.
We do not promise energy or heart benefits from supplements for healthy adults.
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- 1.Mortensen SA et al. The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO. JACC Heart Fail 2014;2:641-649. JACC: Heart Failure
- 2.Qu H et al. Effects of coenzyme Q10 on statin-induced myopathy: an updated meta-analysis of randomized controlled trials. J Am Heart Assoc 2018;7:e009835. JAHA
- 3.Systematic review and meta-analysis of coenzyme Q10 supplementation in statin-associated myopathy (seven randomized trials, 2024). PubMed Central
- 4.Systematic review and meta-analysis of coenzyme Q10 and statin-associated muscle symptoms (Atherosclerosis, 2020; PMID 32179207). Atherosclerosis (via PubMed)