Coenzyme Q10 (COQ10) is a molecule produced in the body. It aids mitochondria during energy production and is a part of the endogenous antioxidant system. It is similar to other pseudovitamin compounds because it is vital for survival, but does not necessarily need to be taken as a supplement. However, there is a potential for deficiency due to suffering a heart attack, taking statins, various disease states, and aging.
It is found in various foods; mainly meat and fish.
Some research suggests minor improvements in the function of blood vessels, leading to reduce blood pressure and improved blood flow. However, more studies are needed to confirm this. The proposed mechanism is related to nitric oxide preservation, as seen with grape seed extract, pycnogenol, and resveratrol.
It seems to be strongly effective for reducing the symptoms of fibromyalgia, but this is based on a handful of small studies, and much more research is needed to confirm this.
It seems to be safe but more research is needed to evaluate its safety in the long-term. In animals, a massive dose of 350mg/kg body weight has been observed to exacerbate the effects of aging, but human studies don't suggest any convincing adverse effects from normal doses.