What does it do? Coenzyme Q10 (CoQ10) is a powerful antioxidant that protects the body from free radicals¹ and helps preserve vitamin E, the major antioxidant of cell membranes and blood cholesterol.² CoQ10 is also called ubiquinone, a name that signifies its ubiquitous (widespread) distribution in the human body. CoQ10 is used by the body to transform food into the energy on which the body runs, ATP.

CoQ10 supplementation has been investigated as a way to improve physical endurance because of its effect on energy production. However, most research shows that CoQ10 does not improve athletic performance.³ In other research, investigators reported no differences in CoQ10 in muscles or blood from patients with fibromyalgia compared to healthy people.⁴

Synthesis of sperm requires considerable energy. Due to its role in energy production, CoQ10 has been studied in infertile men. Preliminary research reports that supplementation of CoQ7, a related molecule, increased sperm counts in a group of infertile men.⁵

Healing of periodontal tissue (the gums of the mouth) may require increased energy production; therefore, researchers have explored the effects of CoQ10 supplementation in people with periodontal disease, which has been linked to CoQ10 deficiency. Double-blind research shows that people with gum disease given CoQ10 achieve better results than those given a placebo.⁶

The role of CoQ10 in energy formation also relates to how the body uses carbohydrates. Preliminary research suggests that a close relative of this nutrient lowered blood sugar levels in a group of people with diabetes.⁷ People with type 2 diabetes have been found to have significantly lower blood levels of CoQ10 compared with healthy people.⁸

Virtually every cell of the human body contains CoQ10. The mitochondria, the area of cells where energy is produced, contain the most CoQ10. The heart and liver contain the greatest amount of CoQ10. It has helped some people with congestive heart failure (CHF)⁹ —an effect reported in an analysis of eight controlled trials¹⁰ and found in some,¹¹ though not all, double-blind studies.^{12 13 14} The beneficial effects of CoQ10 may not be seen until after several months of treatment. Discontinuation of CoQ10 supplementation in people with CHF has resulted in severe relapses and should only be attempted under the supervision of a doctor.¹⁵

Similar improvements have been reported in people with cardiomyopathies—a group of diseases affecting heart muscle. Research (including double-blind studies) in this area has been consistently positive.¹⁶

Also, due to its effect on heart muscle, researchers have studied CoQ10 in people with heart arrhythmias. Preliminary research in this area reported improvement after approximately one month in people with premature ventricular beats (a form of arrhythmia) who also suffer from diabetes.¹⁷

Angina patients taking 150 mg per day of CoQ10 report a greater ability to exercise without experiencing chest pain.¹⁸ This has been confirmed in independent investigations.¹⁹

CoQ10 appears to increase the heart’s tolerance to a lack of oxygen. Perhaps as a result, preliminary research has shown that problems resulting from heart surgery occurred less frequently in people given CoQ10 compared with the control group.²⁰

Muscle mitochondria lack adequate CoQ10 in people with muscular dystrophy, a problem that could affect muscle function. In a double-blind three-month trial, four of eight people with muscular dystrophy had improvements in heart function and sense of well-being when supplementing CoQ10.²¹

Mitochondrial function also appears to be impaired in people with Alzheimer’s disease. Due to CoQ10’s effects on mitochondrial functioning, one group of researchers has given CoQ10 (along with iron and vitamin B6) to several people with Alzheimer’s disease and reported the progression of the disease appeared to have been prevented for one and a half, to two years.²²

CoQ10 also modulates immunity.  Perhaps as a result, a few cases have been reported in which women with metastatic breast cancer (cancer that had spread to other tissues) had a regression of their cancer after treatment with a very large amount of CoQ10 (390 mg per day).²⁴

CoQ10 appears to modulate blood pressure by reducing resistance to blood flow.²⁵ Several trials have reported that supplementation with CoQ10 significantly reduced blood pressure in people with hypertension, usually after ten weeks to four or more months of treatment.²⁶