Coenzyme Q10 (CoQ10)

CoQ10 is said to be useful because of its antioxidant effect and role in energy metabolism. Specific claims include an anticancer effect mediated by immune stimulation, decreased insulin requirements in patients with diabetes, slowed progression of Parkinson disease, efficacy in treatment of heart failure, and protection against anthracycline cardiotoxicity. The most prominent claim may be ameliorating endothelial cell dysfunction that contributes to cardiovascular disease. Although some preliminary studies suggest CoQ10 may be useful in treating these disorders, results are unclear and more testing is needed.

A 2012 meta-analysis evaluated 5 randomized, controlled trials with a total of 194 patients and found a significant improvement in endothelial function, as measured by flow-mediated peripheral arterial dilation (1).

A 2013 meta-analysis of randomized controlled trials suggested that CoQ10 may improve functional status in patients with heart failure (2). However, this meta-analysis consisted of trials mainly of small size and short duration of treatment.

A 2014 randomized, controlled, multicenter study of 420 patients with heart failure showed that CoQ10, 100 mg orally 3 times a day, when added to standard therapy, was safe, relieved symptoms, and reduced major cardiovascular events (3).

A Cochrane review of 11 studies (1573 subjects) concluded there was moderate quality evidence that CoQ10 reduces all‐cause mortality and hospitalization for heart failure; however, there was no convincing evidence to support or refute the use of CoQ10 for heart failure (4).

However, a 2017 meta-analysis of 14 randomized controlled trials (2149 subjects) stated that CoQ10 users had greater exercise capacity and lower mortality than those on placebo (5). A clinical controversy is whether CoQ10 supplementation decreases statin-associated muscle symptoms. Some studies have shown decreases, while others have not. A 2018 meta-analysis of 100 to 600 mg daily of CoQ10 for 30 days to 3 months reported significant decreases in muscle symptoms of pain, weakness, cramps, and tiredness, compared to placebo. A limitation was heterogeneity of the included studies (6).

There are relatively few case reports of gastrointestinal symptoms (eg, loss of appetite, abdominal pain, nausea, vomiting) and central nervous system symptoms (eg, dizziness, photophobia, irritability, headache). Other adverse effects include itching, rash, fatigue, and flu-like symptoms.

CoQ10 may interact with some antihypertensive and chemotherapy drugs.

1. 1. Gao L, Mao Q, Cao J, et al: Effects of coenzyme Q10 on vascular endothelial function in humans: a meta-analysis of randomized controlled trials. Atherosclerosis 221(2):311-316, 2012. doi: 10.1016/j.atherosclerosis.2011.10.027

2. 2. Fotino AD, Thompson-Paul AM, Bazzano LA: Effect of coenzyme Q10 supplementation on heart failure: a meta-analysis. Am J Clin Nutr 97(2):268-275, 2013. doi: 10.3945/ajcn.112.040741

3. 3. Mortensen SA, Rosenfeldt F, Kumar A, et al: The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure results from Q-SYMBIO: a randomized double-blind trial. JACC Heart Fail 2(6):641-649, 2014. doi:10.1016/j.jchf.2014.06.008.

4. 4. Al Saadi T, Assaf Y, Farwati M, et al: Coenzyme Q10 for heart failure. Cochrane Database Syst Rev (2)(2):CD008684, 2021. doi:10.1002/14651858.CD008684.pub3

5. 5. Lie L, Liu Y: Efficacy of coenzyme Q10 in patients with cardiac failure: a meta-analysis of clinical trials. BMC Cardiovasc Disord 17(1):196, 2017. doi: 10.1186/s12872-017-0628-9

6. 6. Qu H, Guo M, Chai H, et al: Effects of coenzyme Q10 on statin-induced myopathy: an updated meta-analysis of randomized controlled trials. J Am Heart Assoc 2;7(19):e009835, 2018. doi: 10.1161/JAHA.118.009835

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

1. National Institutes of Health (NIH), National Center for Complementary and Integrative Health: General information on the use of CoQ10 as a dietary supplement