Coenzyme Q10 (CoQ10) is a very potent antioxidant. It helps to protect cells from free radicals. Free radicals are the byproducts of energy production, which means they are left over products. Even though there are ten common coenzyme Q's, Q10 is the only one found in human tissue. Because of this fact, Q10 tends to diminish with age and therefore must be supplemented in the diet. Preferably supplemented through food sources.
It is used in the treatment of heart disease, high blood pressure and for supporting the immune system. It is used widely in Japan for the treatment of the heart. There is some research that supports Q10 benefiting allergies, asthma and respiratory conditions. It's also been used in the treatment of mental dysfunction, aging, candidiasis, diabetes, obesity and multiple sclerosis.
There have been none documented to my knowledge. You'll always want to ask your healthcare provider for potential side effects, especially if you are taking medication of any kind. When purchasing CoQ10 you'll want it to be bright yellow in color. And always keep CoQ10 away from heat over 115 degrees because it will deteriorate.
The largest amounts of CoQ10 are found in mackerel, salmon and sardines.
Always check with your physician first before taking any supplements.