The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial

Researchers randomly gave 420 people with severe chronic heart failure, meaning the heart cannot pump enough blood, either CoQ10, a substance the body naturally makes, or a look-alike placebo. Neither the participants nor the researchers knew who received which treatment. After 16 weeks, CoQ10 did not clearly improve symptoms or exercise ability. After two years, 15% of the CoQ10 group had a major heart problem or died, compared with 26% of the placebo group, but this was a small trial and the finding needs confirmation.

What this means for you: This study suggests a possible benefit, but it does not prove that CoQ10 helps people live longer or replace standard heart medicines. Do not buy it based on this study alone; discuss it with a healthcare professional.