Potency. You want the CoQ10 product you buy to be potent, don’t you? You want what you pay for. Otherwise, what is the point of buying the supplement?

Dr. William Judy

Dr. William Judy, founder and president of SIBR Research, has tested numerous CoQ10 supplements for their crystal dissolution and absorption and bioavailability. He has found considerable variability in the products. In his book, available from amazon.com, he summarizes the results of his studies.

If you think that all of the CoQ10 supplements offered on amazon.com are equally potent, then you could be wasting your money on an inferior CoQ10 product.

In the May 9th Nutraingredients blog, Hank Schultz reports on the results of a study of a few of the CoQ10 products offered on amazon.com. See here for full article.

Questionable Quality Control of Some CoQ10 Products Sold on Amazon.com

Schultz makes the following points in his blog article [Schultz 2022]:

  • An Illinois-based supplements manufacturer has been testing the potency of CoQ10 and quercetin supplements sold on amazon.com.
  • Some of the CoQ10 supplements sold on amazon.com fail to meet minimum quality standards.
  • Of the eight CoQ10 brands tested, only one delivers the content of Coenzyme Q10 claimed on the label. The other seven contained 30% or less of the Coenzyme Q10 claimed on the label.
  • The exposed CoQ10 brands used a labeling trick to mislead consumers. For example, four of the tested brands claimed a content of 400 mg on the front of the container but then indicated on the back of the container: 400 mg/6% potency.
  • That means that the consumer of these CoQ10 brands is getting 24 mg, less than a quarter of the daily dosage used in serious clinical trials.
  • Three of the eight tested CoQ10 products claimed to be using vegetarian capsule, but testing revealed the capsules to be gelatin capsules.
  • There were similar problems with the quality of quercetin supplements listed for sale on amazon.com.
  • Amazon.com does have quality regulations in place, but cheaters seem to find a way to evade the regulations. So far, amazon.com has not responded to the reports of failing brands. The amazon.com regulations need better enforcement.

N.B. It would be a mistake to think that all CoQ10 supplements are equally bad.

The problem for us consumers is that so few CoQ10 supplements have documented absorption and bioavailability and documented clinical effects. It is difficult to find published journal articles describing studies that used a proper methodology to test the absorption and the bioavailability of the CoQ10 product.

Book Coenzyme Q10 Insider's Guide

Starting on page 46 in my book, Coenzyme Q10: The Substance That Powers Life, there is a section explaining CoQ10 absorption and bioavailability. The book is available from amazon.com. ISBN: 978-87-7776-186-7.

Importance of the Formulation of the CoQ10 Supplement

  • In a 2019 comparative CoQ10 bioavailability study, Prof. Guillermo Lopez-Lluch et al. showed that different CoQ10 supplement formulations yielded very different levels of bioavailability [Lopez-Lluch 2019].
  • By formulation, Prof. Lopez-Lluch means the selection of carrier lipids, the heating/cooling process, and the solubilization of the crystalline CoQ10 raw material.
  • In the Lopez-Lluch study, a ubiquinone CoQ10 supplement with a patented CoQ10 crystal dispersion process gave a bioavailability (measured as area under the curve) that was four times greater than the bioavailability of a similar ubiquinone CoQ10 product lacking the same process.
  • In the Lopez-Lluch study, the above-mentioned ubiquinone CoQ10 supplement with the patented CoQ10 crystal dispersion process gave a bioavailability that was double as great as the bioavailability of a supplement using the ubiquinol form of Coenzyme Q10.

One conclusion from these results has to be that the formulation of the individual CoQ10 product is more important to the absorption and bioavailability than is the form of the product, i.e., whether the Coenzyme Q10 is in the ubiquinone form or in the ubiquinol form.

Both forms, if properly formulated, will give a significant increase in the ubiquinol content in the plasma.

Evidence of Good Formulation from Clinical Studies of CoQ10 Supplementation

In the Q-Symbio study, researchers found that daily adjuvant therapy of chronic heart failure patients with three times 100 mg of Coenzyme Q10 significantly improved the symptoms and survival of the patients, compared to placebo treatment [Mortensen 2014]. The CoQ10 supplement used was the patented ubiquinone CoQ10 supplement tested in the Lopez-Lluch study.

In the KiSel-10 Study, researchers found that daily supplementation of elderly Swedish citizens with two times 100 mg of Coenzyme Q10 and 200 mcg of an organic selenium supplement resulted in significantly improved cardiovascular mortality and improved heart function [Alehagen 2013]. Again, the CoQ10 supplement used in the KiSel-10 Study was the same patented ubiquinone CoQ10 supplement tested in the Lopez-Lluch study.

Conclusion: Potency Differs in Different CoQ10 Products

Truly, the market for CoQ10 supplements in the US is buyer beware market. Not all CoQ10 products are equally well absorbed.

We, as consumers, need to look for scientific documentation to back up marketing claims for CoQ10 products.


Alehagen U, Johansson P, Björnstedt M, Rosén A, Dahlström U. Cardiovascular mortality and N-terminal-proBNP reduced after combined selenium and coenzyme Q10 supplementation: a 5-year prospective randomized double-blind placebo-controlled trial among elderly Swedish citizens. Int J Cardiol. 2013 Sep 1;167(5):1860-6.

Judy WV. The Instability of the Lipid-Soluble Antioxidant Ubiquinol: Part 1-Lab Studies. Integr Med (Encinitas). 2021 Aug;20(4):24-28.

Judy WV. The Instability of the Lipid-Soluble Antioxidant Ubiquinol: Part 2-Dog Studies. Integr Med (Encinitas). 2021 Oct;20(5):26-30.

Judy WV. The Instability of the Lipid-Soluble Antioxidant Ubiquinol: Part 3-Misleading Marketing Claims. Integr Med (Encinitas). 2021 Dec;20(6):24-28.

López-Lluch G, Del Pozo-Cruz J, Sánchez-Cuesta A, Cortés-Rodríguez AB, Navas P. Bioavailability of coenzyme Q10 supplements depends on carrier lipids and solubilization. Nutrition. 2019 Jan;57:133-140.

Mantle D, Dybring A. Bioavailability of Coenzyme Q10: An Overview of the Absorption Process and Subsequent Metabolism. Antioxidants (Basel). 2020;9(5):386.

Mortensen SA, Rosenfeldt F, Kumar A, Dolliner P, Filipiak KJ, Pella D, Alehagen U, Steurer G, Littarru GP; Q-SYMBIO Study Investigators. The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial. JACC Heart Fail. 2014 Dec;2(6):641-9.

Schultz, H. Low potency products still the norm, NOW finds, in CoQ10, quercetin tests. Nutraingredients-asia.com. 2022, May 22.

The information presented in this review article is not intended as medical advice and should not be used as such.

5 June 2022