CoQ10 plays a role in mitochondrial oxidative phosphorylation, aiding in the production of adenosine triphosphate (ATP), which is involved in energy transfer within cells.

[1] The structure of CoQ10 consists of a benzoquinone moiety and an isoprenoid side chain, with the "10" referring to the number of isoprenyl chemical subunits in its tail.

[4][5][6] Although a ubiquitous molecule in human tissues, CoQ10 is not a dietary nutrient and does not have a recommended intake level, and its use as a supplement is not approved in the United States for any health or anti-disease effect.

[1][2] CoQ10 is a component of the mitochondrial electron transport chain (ETC), where it plays a role in oxidative phosphorylation, a process required for the biosynthesis of adenosine triphosphate, the primary energy source of cells.

[1] This membrane is highly folded into structures called cristae, which increase the surface area available for oxidative phosphorylation.

[1] The capacity of this molecule to act as a two-electron carrier (moving between the quinone and quinol form) and a one-electron carrier (moving between the semiquinone and one of these other forms) is central to its role in the electron transport chain due to the iron–sulfur clusters that can only accept one electron at a time and as a free radical–scavenging antioxidant.

[17] CoQ10 levels also may be affected by other genetic defects (such as mutations of mitochondrial DNA, ETFDH, APTX, FXN, and BRAF, genes that are not directly related to the CoQ10 biosynthetic process).

Currently, most clinical centers measure CoQ10 levels in cultured skin fibroblasts, muscle biopsies, and blood mononuclear cells.

There are three major steps: The initial two reactions occur in mitochondria, the endoplasmic reticulum, and peroxisomes, indicating multiple sites of synthesis in animal cells.

[28] Although neither a prescription drug nor an essential nutrient, CoQ10 is commonly used as a dietary supplement with the intent to prevent or improve disease conditions, such as cardiovascular disorders.

[41] Although CoQ10 has been studied as a potential remedy to treat purported muscle-related side effects of statin medications, the results were mixed.

Absorption as a pharmacological substance follows the same process as that of lipids; the uptake mechanism appears to be similar to that of vitamin E, another lipid-soluble nutrient.

[16] This process in the human body involves secretion into the small intestine of pancreatic enzymes and bile, which facilitates emulsification and micelle formation required for absorption of lipophilic substances.

[44] Food intake (and the presence of lipids) stimulates bodily biliary excretion of bile acids and greatly enhances absorption of CoQ10.

[2] In some studies, a second plasma peak was observed approximately 24 hours after administration, probably due to enterohepatic recycling and redistribution from the liver to circulation.

[47] In contrast to the intake of CoQ10 as a constituent of food, such as nuts or meat, from which CoQ10 is normally absorbed, there is a concern about CoQ10 bioavailability when it is taken as a dietary supplement.

[53] Facilitating drug absorption by increasing its solubility in water is a common pharmaceutical strategy and also is successful for CoQ10.

Various approaches have been developed to achieve this goal, with many of them producing significantly better results over oil-based soft gel capsules despite the many attempts to optimize their composition.

[1] The most common side effects are gastrointestinal symptoms (nausea, vomiting, appetite suppression, and abdominal pain), rashes, and headaches.

[2] The observed safe level risk assessment method indicated that the evidence of safety is acceptable at intakes up to 1200 mg per day.

[61] In the developed world, the estimated daily intake of CoQ10 has been determined at 3–6 mg per day, derived primarily from meat.

[63] In 1950, a small amount of CoQ10 was isolated from the lining of a horse's gut, a compound initially called substance SA, but later deemed to be quinone found in many animal tissues.

[64] In 1957, the same compound was isolated from mitochondrial membranes of beef heart, with research showing that it transported electrons within mitochondria.