Coenzyme Q10, also known as ubiquinone, ubidecarenone, coenzyme Q, and abbreviated at times to CoQ10 or Q10 is a coenzyme that is ubiquitous in the bodies of most animals. It is a 1,4-benzoquinone, where Q refers to the quinone chemical group and 10 refers to the number of isoprenyl chemical subunits in its tail. This fat-soluble substance, which resembles a vitamin, is present in most eukaryotic cells, primarily in the mitochondria. It is a component of the electron transport chain and participates in aerobic cellular respiration, which generates energy in the form of ATP. Ninety-five percent of the human body’s energy is generated this way. Therefore, those organs with the highest energy requirements—such as the heart, liver, and kidney—have the highest CoQ10 concentrations. There are three redox states of CoQ10: fully oxidized (ubiquinone), semiquinone (ubisemiquinone), and fully reduced (ubiquinol). The capacity of this molecule to act as a 2 electron carrier (moving between the quinone and quinol form) and 1 electron carrier (moving between the semiquinone and one of these other forms) is central to its role in the electron transport chain, and as radical-scavenging antioxidant. Coenzyme Q10 works foremost in every cell of your body to synthesize energy. In cells' mitochondria, CoQ10 helps generate adenosine triphosphate (ATP), your body's energy currency. It makes sense that organs with the highest energy needs - including the heart, liver, and kidneys - contain large amounts of CoQ10. Among its roles, ubiquinol protects fats, protein, low-density lipoprotein (LDL, a cholesterol transporter), and DNA from oxidative damage. It also regenerates vitamin E, another powerful antioxidant. Even though Coenzyme Q10 is a supplement and occurs naturally in your body, it doesn't mean that it's side effect free. However, most CoQ10 side effects are mild. Some people may experience allergies to increased Coenzyme Q10. There have been some reports of rashes and itching. Other side effects include a lowering of blood sugar within the body. CoQ10 is not approved by the U.S. Food and Drug Administration (FDA) for the treatment of any medical condition. It is sold as a dietary supplement. In the U.S., supplements are not regulated as drugs, but as foods. How CoQ10 is manufactured is not regulated and different batches and brands may vary significantly. As an over-the-counter nutritional supplement, CoQ10 has been used to treat many things, from heart disease, high blood pressure and high cholesterol to diabetes, breast cancer and gum disease. CoQ10 supposedly can help with immune deficiencies, increase fertility, treat Alzheimer's and Parkinson's, reduce ringing in the ears, delay aging and improve skin, and increase athleticism The key benefits of coenzyme Q10 are summarized as below. A 2014 Cochrane Collaboration meta-analysis found "no convincing evidence to support or refute" the use of CoQ10 for the treatment of heart failure. Evidence with respect to preventing heart disease in those who are otherwise healthy is also poor. A 2009 Cochrane review concluded that studies looking at the effects of CoQ10 on blood pressure were unreliable, and therefore no conclusions could be made regarding its effectiveness in lowering blood pressure. Available evidence suggests that "CoQ10 is likely ineffective in moderately improving" the chorea associated with Huntington's disease. No large well-designed clinical trials of CoQ10 in cancer treatment have been done. The National Cancer Institute identified issues with the few, small studies that have been done stating, "the way the studies were done and the amount of information reported made it unclear if benefits were caused by the CoQ10 or by something else". The American Cancer Society has concluded, "CoQ10 may reduce the effectiveness of chemo and radiation therapy, so most oncologists would recommend avoiding it during cancer treatment. Lower levels of CoQ10 have also been observed in people with Parkinson's disease. Preliminary research has found that increasing CoQ10 may increase levels of the neurotransmitter dopamine, which is thought to be lowered in people with Parkinson's disease. It has also been suggested that CoQ10 might protect brain cells from damage by free radicals. A small, randomized controlled trial examined the use of 360 mg CoQ10 or a placebo in 28 treated and stable Parkinson's disease patients. After 4 weeks, CoQ10 provided a mild but significant significant mild improvement in early Parkinson's symptoms and significantly improved performance in visual function. As an antioxidant, Coenzyme Q10 helps protect your body against the harmful effects of toxins and also aids the absorption of beneficial vitamins and minerals. Antioxidants are sometimes credited with boosting weight loss, possibly due to their energising effect on the body helping increase the fat-burning benefits of exercise.