What Is Coenzyme Q10?

Coenzyme Q10, a vitamin-like compound discovered in 1957, plays a crucial role in the cells’ energy-producing mitochondria. It also acts as a powerful antioxidant, meaning that it helps neutralize cell-damaging free radicals. Manufactured by all cells in the body, CoQ10 is also found in small amounts in some foods, notably meat and fish. CoQ10 is one of many substances in the body that tend to decline as people age or develop certain diseases (such as some heart conditions, Parkinson’s disease, and asthma). That doesn’t necessarily mean, however, that lower levels of CoQ10 cause disease or that supplemental CoQ10 will combat disease or reverse the effects of aging. Some medications, including certain statins, beta-blockers, and antidepressants, can reduce CoQ10 levels in the body, but it’s not clear whether this results in health problems.

Claims, purported benefits: Helps treat, or possibly even prevent, heart disease, hypertension, Parkinson’s disease, diabetes, certain cancers, migraines, HIV/ AIDS, infertility, gum disease, allergies, and so on. It’s said to boost immunity, enhance athletic performance, aid memory, and slow aging. Prevents the uncommon adverse effects of statin drugs.

What the science says: An analysis of 12 studies of people with hypertension, in the Journal of Human Hypertension in 2007, found that CoQ10 lowered systolic blood pres- sure 11 to 17 points, and diastolic 8 to 10 points. This may be due to CoQ10’s ability to dilate blood vessels. The Natural Standard, which evaluates complementary and alternative therapies, gives CoQ10 a “B” for hypertension, citing “good” evidence for this use but also the need for more studies.

Heart conditions. People with cardiac disease often have low levels of CoQ10, and cells of the heart are sensitive to reductions in CoQ10. According to a 2010 review in Nutrition, heart failure patients with low CoQ10 have higher death rates. CoQ10 has shown a range of heart benefits, including a reduction in arrhythmias after bypass surgery and improvements in cardiac function indicators in people with heart failure. CoQ10 may benefit the cardiovascular system through its antioxidant and anti-inflammatory effects and by improving blood vessel function. But there is not enough evidence to recommend it for people with coronary heart disease.

Research on CoQ10 as a treatment for heart failure has been inconsistent. A large clinical trial in 2013 found that it can reduce mortality rates from heart failure; a 2013 Cochrane review concluded that it does not; a 2013 meta-analysis suggested that it may improve ejection fraction (which indicates how well the heart can pump blood) in patients with heart failure. CoQ10 is prescribed for certain heart ailments in Japan and several European countries.

Parkinson’s disease. A 2002 study from the University of California-San Diego found that very large doses of CoQ10 appeared to slow the progression of early Parkinson’s disease and to improve daily life for patients. Though a 2007 study in the same journal did not find a benefit of CoQ10, it included people with more advanced disease and used lower doses for a shorter time. In 2014, the long-awaited Coenzyme Q10 Study in Early Parkinson’s Disease found no benefits from high-dose CoQ10.

For statin users. Statins inhibit an enzyme that’s integral to cholesterol production in the body. This enzyme is also involved in the production of CoQ10, so statins reduce blood levels of it as well. It’s not known if statins’ effect on CoQ10 contributes to their adverse effects on muscles. Studies on CoQ10 supplements in statin users have been small and short and have had conflicting results. In 2015, an analysis of six studies, published in Mayo Clinic Proceedings, found that statin users who took CoQ10 supplements were just as likely to develop muscle pain as those taking a placebo. Nevertheless, the researchers noted, larger studies on CoQ10 and statins are underway and may still find benefits.

Our advice: The claims for CoQ10 are overblown, and there’s no reason to take the supplement if you are healthy. No one knows how much to take or which formulation, if any, is best. Its long-term safety is still unknown. If you have heart disease, high blood pressure, or Parkinson’s disease and are considering CoQ10, discuss it with your doctor first.