In a double-blind, cross-over study, Professor Guillermo Lopez-Lluch and a team of researchers at the Pablo de Olavide University in Sevilla, Spain, have demonstrated that the composition and the formulation of the supplement is very important to the absorption and bio-availability of the Coenzyme Q10.

On this website, we review the results of clinical trials of the effects of oral Coenzyme Q10 supplementation.  We high-light human studies that show the following significant health benefits of taking a well-formulated CoQ10 supplement:

  • Improved symptoms and survival of heart failure patients
  • Reduced risk of death from heart disease and better maintained heart function among senior citizens
  • Improved quality of life for chronic fatigue syndrome patients
  • Faster recovery with fewer complications following heart surgery
  • Lowered systolic and diastolic blood pressure
  • Reduced frequency and intensity of migraine headaches

Why the need for CoQ10 supplementation?

Bio-synthesis of CoQ10 falling with increasing age.

Yes, our bodies do synthesize Coenzyme Q10 in almost all cells; however, the bio-synthesis of Coenzyme Q10 is a complicated multi-step process, and the extent of Coenzyme Q10 bio-synthesis decreases with increasing age once we pass our 20s.

Insufficient uptake of CoQ10 from the diet.

Moreover, it is difficult to get enough Coenzyme Q10 from our food alone to make up the difference in the declining endogenous production of CoQ10.  Remember, too, that it becomes more difficult to extract nutrients from our food as we get older.

Drug interference with CoQ10 absorption.

Last but not least, we need to consider that various drug interactions with Coenzyme Q10 can reduce the body’s bio-synthesis of CoQ10 and/or the body’s absorption of CoQ10 from external sources.  In this context, we think of the statin medications that have been proved to inhibit the bio-synthesis of CoQ10.  But, statin medications are far from the only medications to affect adversely the bio-synthesis or absorption of CoQ10.

What are the biological effects of CoQ10 supplements?

Production of ATP energy.

Coenzyme Q10 in the ubiquinone form is essential to produce ATP energy – the basic form of cellular energy in humans.  Think about this: Low Coenzyme Q10 concentrations resulting in energy starvation of the heart muscle cells is directly and unequivocally related to increased risk of heart failure.  Supplementation can increase the plasma and tissue CoQ10 concentrations.

Antioxidant protection against harmful radicals.

Coenzyme Q10 in its reduced form, ubiquinol, the form that results from the reduction of CoQ10 in the process of producing ATP energy, is an important fat-soluble antioxidant.  CoQ10 supplements provide extra antioxidant protection of proteins including lipoproteins, fatty acids, and DNA against the harmful radicals produced as by-products during the production of ATP energy.

Regulation of endothelial function.

Endothelial dysfunction is directly implicated in the process of atherogenesis (the forming of plaques in the inner lining of arteries) and in the forming of blood clots in the arteries. Coenzyme Q10 supplementation improves the function of the vascular endothelial cells [Belardinelli 2008].

Reduction of inflammation and increase in endogenous antioxidant enzyme activity.

Supplementation with Coenzyme Q10 is associated with reductions in the levels of bio-markers for systemic inflammation and with increases in the activity levels of the endogenous antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase [Lee 2012, 2013].

How much Coenzyme Q10 on a daily basis?

Basically, our need for Coenzyme Q10 supplementation will vary according to number of factors:

  • Age
  • Body mass index
  • Diet
  • Exercise level
  • Gender
  • Health and physical condition (blood pressure, diabetes, obesity, smoking)

To achieve a good prophylactic and/or therapeutic effect from CoQ10 supplementation, we need to take daily doses that will raise our plasma CoQ10 concentrations into the range from 2.5 to 3.5 micrograms per milliliter.

Remember, without CoQ10 supplementation, most of us will have plasma CoQ10 concentrations somewhere between 0.65 and 1.5 micrograms per milliliter.

What daily dosages of CoQ10 were used in clinical studies?

Q-Symbio study of the effect of CoQ10 on heart failure symptoms?

300 milligrams per day, taken three times daily with meals, significantly improved the symptoms and survival of chronic heart failure patients. [Mortensen 2014].

KiSel-10 study of CoQ10 and selenium for independently living senior citizens?

200 milligrams per day, taken twice daily with meals, in combination with 200 micrograms of a high-selenium yeast preparation, helped senior citizens maintain better heart function and reduced the risk of death from heart disease [Alehagen 2015].

Italian studies of CoQ10 and oxidative stress and endothelial function?

Doses of 200–300 milligrams per day improved functional capacity, endothelial function, and left ventricular contractility in chronic heart failure patients without any side effects [Belardinelli 2008].

Taiwanese studies of Coq10 and endogenous antioxidant enzymes?

Doses of 300 milligrams per day significantly enhanced the activity of the endogenous antioxidant enzymes and lowered the levels of bio-markers of inflammation [Lee 2013].

Take-home message about CoQ10 supplements

  • CoQ10 is a difficult substance to deliver to the body.  It has a low absorption rate.
  • There is much diversity in the compositions and formulations of CoQ10 supplements and, consequently, in the absorption rates of different CoQ10 supplements.
  • The cheaper CoQ10 supplements on the market can have such a low absorption and so few beneficial health effects that they are nearly useless.

In the long run, the well-formulated, well-documented CoQ10 supplement will prove to be the best investment.

Read our key article on CoQ10 as adjuvant therapy for heart failure



Alehagen, U., Aaseth, J., & Johansson, P. (2015). Reduced Cardiovascular Mortality 10 Years after Supplementation with Selenium and Coenzyme Q10 for Four Years: Follow-Up Results of a Prospective Randomized Double-Blind Placebo-Controlled Trial in Elderly Citizens. Plos One, 10(12), e0141641.

Belardinelli, R., Tiano, L., & Littarru, G. P. (2008). Oxidative stress, endothelial function and coenzyme Q10. Biofactors, 32(1-4):129-33.

Lee, B., Tseng, Y., Yen, C., & Lin, P. (2013). Effects of coenzyme Q10 supplementation (300 mg/day) on antioxidation and anti-inflammation in coronary artery disease patients during statins therapy: a randomized, placebo-controlled trial. Nutrition Journal, 12(1), 142. doi:10.1186/1475-2891-12-142

Mortensen, S. A., Rosenfeldt, F., Kumar, A., Dolliner, P., Filipiak, K. J., Pella, D., & Littarru, G. P. (2014). The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial. JACC. Heart Failure, 2(6), 641-649.

Disclaimer: The information contained in this review article is not intended as medical advice and should not be used in that way.