Coenzyme Q10

What is CoQ10?

Coenzyme Q10, or ubiquinone, is a fat-soluble molecule synthesized by the liver that plays a vital role in generating cellular energy for the body, as well as acting as a potent antioxidant.

Chemical structure of ubiquinone (Coenzyme Q10)

What does supplementing with CoQ10 do?

CoQ10 is cited as beneficial to a host of pre-existing medical conditions and complaints.

  • There is some evidence to link CoQ10 with the capacity to protect the loss of neurons and therefore could be of use for patients with Parkinson’s disease or other central nervous system disorders. [1][2]
  • CoQ10 can also contribute to a healthy heart, beneficial to sufferers of cardiovascular diseases. [3][4]
  • For asthma sufferers, CoQ10 has been shown to reduce the necessary doses of preventative corticosteroids, reducing the likelihood of mitochondrial dysfunction associated with long term use of corticosteroids. [5]
  • Meta-analysis of 12 clinical trials shows it can reduce blood pressure in hypertensive patients. [6]
  • CoQ10 has also shown positive results in improving male fertility [7][8] and in preventing pre-eclampsia. [9]

It’s also worth pointing out that statins (HMG-CoA reductase inhibitors) block the pathway of production of Coenzyme Q10 (and can lower CoQ10 levels by up to 40% [10]), suggesting that where statins are prescribed, CoQ10 should also be administered.

Which form of CoQ10 should I take?

Coenzyme Q10 can exist in two forms; the oxidised form ubiquinone, and the reduced form ubiquinol.

Popular wisdom has it that the reduced form is much better than the oxidised, with many people shunning ubiquinone altogether, in favour of ubiquinol that is advertised as “up to 6 times stronger”. But is that reaction warranted? Is ubiquinol really that much better?

Chemical structure of the reduced form of CoQ10, ubiquinol.

Unfortunately the science around ubiquinol is clouded and confounded by commercial interests, with a small number of companies sponsoring research designed to show it as more effective than its oxidised rival.

Although ubiquinol is more polar than ubiquinone, and hence more water soluble, the isoprene tail of ubiquinone and ubiquinol makes both of these molecules highly lipid soluble. Any variance in hydrophilicity (water solubility) between them is not likely to affect bioavailability as both molecules will be lymphatically absorbed via carrier-mediated diffusion.

“Plasma CoQ10 is present almost entirely (about 95%) in its reduced form as ubiquinol in healthy subjects. The redox status is not affected by gender or race. Furthermore, orally ingested CoQ10, whether as ubiquinone or as ubiquinol and regardless of the dose, appears in circulation as ubiquinol with no change or very little change in its redox status. This shows that there is an efficient mechanism to convert orally administered CoQ10 as ubiquinone to ubiquinol in vivo. There is evidence to show that this reduction takes place in the intestine following absorption before CoQ10 enters the lymphatic system.” [11]

Following absorption, 95% of CoQ10 in the lymph or blood will be in the reduced form, ubiquinol. This is true regardless of whether ubiquinone or ubiquinol was administered. [11] In the blood, ubiquinol acts as an antioxidant, preventing reactions that could cause damage or death to a cell. Oxidative theory suggests that CoQ10 is an “important anti-risk factor” for the thickening of arterial walls and associated vascular complications caused by cholesterol. [12]
In the mitochondria of cells, ubiquinol is rapidly converted to the oxidised form ubiquinone, where it aids in the synthesis of energy via ATP. [13]

Several studies have demonstrated that the most important factors determining plasma CoQ10 levels following oral CoQ10 administration are:

  • That the CoQ10 be solubilised. Plain crystalline CoQ10 powder is extremely poorly absorbed. [14]

“In the present study… non-solubilized coenzyme Q10 powder, was observed to be only minimally absorbed following a 180 mg dose. Based upon these results it can be predicted that only slight increases in coenzyme Q10 plasma concentration will occur with chronic supplementation of a product containing this non-solubilized powder form of Q10.” [14]

“The response following ingestion of solubilized formulations of CoQ10 is much greater indicating their superior bioavailability as compared with non-solubilized powder-based CoQ10 products.” [11]

  • That doses be split. [11]

“Not surprisingly, the efficiency of absorption decreases as the dose increases, and this is particularly striking at high doses. Split dosing is superior to single dosing with pharmacologic doses of CoQ10.” [11]

By comparison, the redox form of CoQ10 administered (ubiquinol or ubiquinone) has a much smaller effect on plasma CoQ10 levels.

A = Liquid containing solubilized coenzyme Q10
B = Soft capsule containing ubiquinol
C = Fully-solubilized coenzyme Q10 (ubiquinone)
D = Non-solubilized Q10 powder [14]

 In one experiment a 180mg dose of CoQ10 administered as (solubilised) ubiquinol reached a peak plasma concentration (Cmax) 15% higher than that of (solubilised) ubiquinone, and caused a 23% greater increase in plasma CoQ10 per 100mg. [14]

These marginal increases in bioavailability are overshadowed by the significantly higher cost associated with ubiquinol, lack of clinical trials on the effects of ubiquinol compared to the abundance of clinical data on ubiquinone, and the fact that ubiquinone and ubiquinol form a redox pair that are easily converted to one another.

[1] J Neurochem. 2009 Jun;109(5):1427-39. Epub 2009 Mar 28. Combination therapy with coenzyme Q10 and creatine produces additive neuroprotective effects in models of Parkinson’s and Huntington’s diseases. Yang L, Calingasan NY, Wille EJ, Cormier K, Smith K, Ferrante RJ, Beal MF.
[2] CNS Neurol Disord Drug Targets. 2008 Oct;7(4):321-42.Drugs used to treat Parkinson’s disease, present status and future directions. Abdel-Salam OM.
[3] Mitochondrion. 2007 Jun;7 Suppl:S154-67. Epub 2007 Mar 16. Coenzyme Q10 in cardiovascular disease. Pepe S, Marasco SF, Haas SJ, Sheeran FL, Krum H, Rosenfeldt FL
[4] Altern Ther Health Med. 2009 May-Jun;15(3):44-52. Metabolic cardiology: an integrative strategy in the treatment of congestive heart failure. Sinatra ST.
[5] Biofactors. 2005;25(1-4):235-40. Coenzyme Q10 supplementation reduces corticosteroids dosage in patients with bronchial asthma. Gvozdjáková A, Kucharská J, Bartkovjaková M, Gazdíková K, Gazdík FE.
[6] Rosenfeldt FL, Haas SJ, Krum H, Hadj A, Ng K, Leong J-Y, et al. Coenzyme Q10 in the treatment of hypertension: a meta-analysis of the clinical trials. J Hum Hypertens. 2007 Apr;21(4):297–306.
[7] Biofactors. 2005;25(1-4):165-74. An update of Coenzyme Q10 implications in male infertility: biochemical and therapeutic aspects. Mancini A, De Marinis L, Littarru GP, Balercia G.
[8] J Androl. 1994 Nov-Dec;15(6):591-4. Coenzyme Q10 concentrations in normal and pathological human seminal fluid. Mancini A, De Marinis L, Oradei A, Hallgass ME, Conte G, Pozza D, Littarru GP.
[9] J Gynaecol Obstet. 2009 Apr;105(1):43-5. Epub 2009 Jan 19. Coenzyme Q10 supplementation during pregnancy reduces the risk of pre-eclampsia. Teran E, Hernandez I, Nieto B, Tavara R, Ocampo JE, Calle A.
[10] Ghirlanda G, Oradei A, Manto A, Lippa S, Uccioli L, Caputo S, et al. Evidence of plasma CoQ10-lowering effect by HMG-CoA reductase inhibitors: a double-blind, placebo-controlled study. J Clin Pharmacol. 1993 Mar;33(3):226–9.
[11] Bhagavan HN, Chopra RK. Plasma coenzyme Q10 response to oral ingestion of coenzyme Q10 formulations. Mitochondrion. 2007 Jun;7 Suppl:S78–88.
[12] Mol Aspects Med. 1997;18 Suppl:S137-44.Dose-related decrease of serum coenzyme Q10 during treatment with HMG-CoA reductase inhibitors. Mortensen SA, Leth A, Agner E, Rohde M. Arch
[13] Ernster L, Dallner G. Biochemical, physiological and medical aspects of ubiquinone function. Biochim. Biophys. Acta. 1995 May 24;1271(1):195–204.
[14] Miles MV, Horn P, Miles L, Tang P, Steele P, DeGrauw T. Bioequivalence of coenzyme Q10 from over-the-counter supplements. Nutrition Research. 2002 Aug;22(8):919–29.

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