| Names | |
|---|---|
| IUPAC name 2-[(2E,6E,10E,14E,18E,22E,26E,30E,34E)-3,7,11,15,19,23,27,31,35,39-decamethyltetraconta-2,6,10,14,18,22,26,30,34,38-decaenyl]-5,6-dimethoxy-3-methyl-benzene-1,4-diol | |
| Other names Reduced CoQ10, unoxidized CoQ10, CoQ10H2, or dihydroquinone | |
| Identifiers | |
| |
3D model (JSmol) | |
| ChemSpider |
|
| MeSH | C003741 |
| UNII | |
| |
| |
| Properties | |
| C59H92O4 | |
| Molar mass | 865.381 g·mol−1 |
| Appearance | off-white powder |
| Melting point | 45.6 °C (114.1 °F; 318.8 K) |
| practically insoluble in water | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Aubiquinol is an electron-rich (reduced) form ofcoenzyme Q (ubiquinone). The term most often refers toubiquinol-10, with a 10-unit tail most commonly found in humans
The natural ubiquinol form of coenzyme Q is 2,3-dimethoxy-5-methyl-6-poly prenyl-1,4-benzoquinol, where the polyprenylated side-chain is 9-10 units long inmammals. Coenzyme Q10 (CoQ10) exists in threeredox states, fullyoxidized (ubiquinone), partiallyreduced (semiquinone or ubisemiquinone), and fully reduced (ubiquinol). The redox functions of ubiquinol incellular energy production andantioxidant protection are based on the ability to exchange twoelectrons in a redox cycle between ubiquinol (reduced) and the ubiquinone (oxidized) form.[1][2]
Because humans can synthesize ubiquinol, it is not classed as avitamin.[3]
CoQ10 is not well absorbed into the body.[4] Since the ubiquinol form has two additional hydrogens, it results in the conversion of twoketone groups intohydroxyl groups on the active portion of the molecule. This causes an increase in thepolarity of the CoQ10 molecule and may be a significant factor behind the observed enhanced bioavailability of ubiquinol.
Studies have shown that Ubiquinol, coenzyme Q10 (CoQ10), may reduce systolic blood pressure in adults. A 2025meta-analysis of randomized controlled trials published in the International Journal of Cardiology Cardiovascular Risk and Prevention concluded that a daily dose of CoQ10 below 200 mg may be an effective adjunctive therapy for the reduction insystolic blood pressure (SBP).[5]
Ameta-analysis published in the academic journalAdvances in Nutrition assessed CoQ10 dosing to lower systolic blood pressure in patients withCardiometabolic Disorders. The assessment included 1,831 individuals across 26 studies. Conclusions showed that CoQ10 supplements may be potentially effective for clinically reducing SBP in people with cardiometabolic disorders, such asType 2 diabetes orDyslipidemia. The dose recommended was 100 – 200mg per day.[6]
Varying amounts of ubiquinol are found in different types of food. An analysis of a range of foods found ubiquinol to be present in 66 out of 70 items and accounted for 46% of the total coenzyme Q10 intake in the Japanese diet. The following chart is a sample of the results.[7]
| Food | Ubiquinol (μg/g) | Ubiquinone (μg/g) |
|---|---|---|
| Beef (shoulder) | 5.36 | 25 |
| Beef (liver) | 40.1 | 0.4 |
| Pork (shoulder) | 25.4 | 19.6 |
| Pork (thigh) | 2.63 | 11.2 |
| Chicken (breast) | 13.8 | 3.24 |
| Mackerel | 0.52 | 10.1 |
| Tuna (canned) | 14.6 | 0.29 |
| Yellowtail | 20.9 | 12.5 |
| Broccoli | 3.83 | 3.17 |
| Parsley | 5.91 | 1.57 |
| Orange | 0.88 | 0.14 |
Ubiquinol is a benzoquinol and is the reduced product ofubiquinone also calledcoenzyme Q10. Its tail consists of 10isoprene units.

The reduction of ubiquinone to ubiquinol occurs in Complexes I & II in theelectron transfer chain. The Q cycle[8] is a process that occurs incytochrome b,[9][10] a component of Complex III in theelectron transport chain, and that converts ubiquinol to ubiquinone in a cyclic fashion. When ubiquinol binds to cytochrome b, the pKa of the phenolic group decreases so that the proton ionizes and the phenoxide anion is formed.

If the phenoxide oxygen is oxidized, the semiquinone is formed with the unpaired electron being located on the ring.
