Dr. Judy's book: An Insider's Guide to Coenzyme Q10.

Dr. William Judy, founder and president of SIBR Research, advises against taking a vitamin C supplement within an hour of taking a CoQ10 capsule. In his book, Insider’s Guide to Coenzyme Q10, Dr. Judy summarizes the CoQ10 clinical research results. The book is available from amazon.com.

Human adults’ bio-synthesis of the essential bio-nutrient Coenzyme Q10 declines with increasing age [Kalén].  That is unfortunate.

We humans need sufficient quantities of Coenzyme Q10 for various biological functions:

  • cellular production of ATP energy
  • antioxidant protection of the cells against oxidative damage
  • maintenance of endothelial function in blood vessels
  • anti-inflammatory effects

Coenzyme Q10 Supplementation and Beyond

We can take a daily Coenzyme Q10 supplement, of course, and we should.  However, we should be very careful.

Commercially available CoQ10 supplements vary considerably in their formulation and in their absorption and bio-availability.  A cheap 30-cents-per day CoQ10 supplement at the supermarket or drugstore is most likely a poorly absorbed and ineffective supplement.

We should always be wary of marketing claims for high absorption and superior absorption and so on.  We should expect scientific documentation of the absorption and efficacy of the CoQ10 supplement.

How to Enhance Endogenous Production of Coenzyme Q10?

Exercise comes immediately to mind.  There is some thought that regular exercise can benefit CoQ10 bio-synthesis and various aspects of mitochondrial function, but the jury is still out [Deichmann].

The big question is: what are the substances that we need to be careful about, what are the substances that can act as antagonists or inhibitors of the bio-synthesis of Coenzyme Q10 and of the biological effect of the Coenzyme Q10 in our cells?

Dr. William Judy.

Dr. Judy’s experience as a clinical researcher and lab scientist has been that concurrent vitamin C and vitamin E intake reduces the absorption of the Coenzyme Q10 considerably. Dr. Judy’s own research shows that vitamins C and E will convert the ubiquinol form of Coenzyme Q10 in soft-gel capsules to the ubiquinone form by up to 30%.

Vitamin C and Coenzyme Q10

Yes, some vitamin C is needed for the bio-synthesis of Coenzyme Q10; however, it may not be a good idea to take large quantities of vitamin C together with your daily CoQ10 capsule.

Professor Guillermo Lopez-Lluch has speculated that too much simultaneous intake of vitamin C and Coenzyme Q10 might affect the net incorporation of Coenzyme Q10 into blood plasma [Lopez-Lluch].

Vitamin E and Coenzyme Q10

Speaking at the 9th international conference of the International Coenzyme Q10 Association at Columbia University, New York, in the summer of 2018, cardiologist Dr. Peter H. Langsjoen reported that high doses of Vitamin E together with CoQ10 supplements can reduce the effectiveness of the Coenzyme Q10 supplements.  In a 2005 study, Dr. Langsjoen and colleagues showed that concurrent supplementation with 3000 international units of Vitamin E (3 x 1000 international units per day) and 600 milligrams of Coenzyme Q10 (3 x 200 milligrams per day) in a four-week course of supplementation resulted in a nearly 30% decline in plasma Coenzyme Q10 levels.   1,200 international units of vitamin E (400 international units three times per day) simultaneously with supplemental CoQ10 resulted in nearly 14% decline in the CoQ10 level in one subject supplemented with 600 milligrams of CoQ10 (200 three times per day) and no decline in the CoQ10 level in another subject supplemented with 300 milligrams of CoQ10 (100 mg three times per day) [Langsjoen].

Vitamin E has sometimes been referred to as a synergist of Coenzyme Q10. This confusion may have arisen because ubiquinol, the reduced form of Coenzyme Q10, not only acts as a free-radical-chain-breaking antioxidant itself but also acts to regenerate alpha-tocopherol, the active form of Vitamin E.  Thus, Coenzyme Q10 and vitamin E can be considered a fat-soluble antioxidant duo of primary importance [Littarru].

It could be that vitamin E and Coenzyme Q10 compete for absorption in the small intestine absorption cells; alternatively, it could be that vitamin E and Coenzyme Q10 compete for lipoprotein transport in the blood. To stay on the safe side, it may be best not to take more than 300 international units of vitamin E daily and, in that way, avoid the risk of inhibiting the function and effect of Coenzyme Q10 in the body.

PABA (para-aminobenzoic acid) and Coenzyme Q10

PABA, a substance similar to the B vitamins, is sold as a dietary supplement.  It is a competitive inhibitor of the CoQ10 bio-synthetic pathway enzyme, CoQ2. In a cell study, PABA treatment resulted in a 54 % decrease in neuronal CoQ10 status (p < 0.01). The reduction in neuronal CoQ10 status was associated with a progressive decrease in mitochondrial respiratory chain enzyme activities, with a 67.5 % decrease in cellular ATP production, and with a four-fold increase in mitochondrial oxidative stress [Duberley].

At the conference of the International Coenzyme Q10 Association in New York in 2018, a Ph.D. student presented evidence PABA supplementation is associated with a 50% reduction in cellular Coenzyme Q10 levels compared to control subjects not taking a PABA supplement.

Fish oil and Coenzyme Q10 in the Same Capsule

At SIBR Research, Dr. William Judy and his research team have tested the absorption of supplement formulations combining Coenzyme Q10 and fish oil.  To his surprise, Dr. Judy found very poor absorption of the Coenzyme Q10 product when it was mixed with various fish oils.  Without the fish oils, the Coenzyme Q10 product had a much better absorption.  Dr. Judy theorized that something in the fish oil was interfering with the monoglyceride carrier in the Coenzyme Q10 product [Judy].

Medical Drugs as CoQ10 Antagonists and Inhibitors

The list of medical drugs that counteract or inhibit the bio-synthesis and/or the bio-medical effects of Coenzyme Q10 supplements is a long list.  Please click here for a separate article on this topic.

If you are taking prescription medications, it is a good idea to ask your physician or pharmacist whether the drugs are likely to interfere with your body’s bio-synthesis of Coenzyme Q10 or your body’s use of Coenzyme Q10.

Statin Medications’ Inhibition of CoQ10 Bio-Synthesis

Especially prominent as an inhibitor of CoQ10 bio-synthesis are the statin medications.  Okuyama and Langsjoen [2015] have explained pharmacological mechanisms by which statin medications may actually stimulate the development and progression of atherosclerosis and heart failure.  They fear that the use of statin medications may play a role in coronary artery calcification and may be mitochondrial toxins that impair heart muscle cell function.  Statins have the following known deleterious health effects:

  • depletion of Coenzyme Q10 and thereby of ATP
  • inhibition of the synthesis of vitamin K2
  • inhibition of the synthesis of selenoproteins such as glutathione peroxidase

Okuyama and Langsjoen [2015] have urged that statin treatment guidelines be urgently re-evaluated.

Summary: CoQ10 for Better Health-Related Quality of Life

  • Our bodies produce less and less Coenzyme Q10 as we get older [Kalén].
  • Various substances, notably statin medications, can inhibit the body’s bio-synthesis of Coenzyme Q10 [Okuyama].
  • CoQ10 supplements are safe, well-tolerated, and affordable, but there is great variability in the extent of their absorption and bio-availability [Lopez-Lluch].  Buyer beware!
  • In the KiSel-10 Study, daily supplementation of normal healthy senior citizens (average age at baseline: 78 years) with Coenzyme Q10 (200 milligrams/day) and high-selenium yeast (200 micrograms/day) for four years showed a 53% reduction in cardiovascular related mortality risk, improved heart function seen on echocardiography, and better health-related quality of life compared to placebo [Alehagen].
  • In the Q-Symbio Study, daily supplementation of chronic heart failure patients (average age at baseline: 63 years) with 3 times 100 mg/day of Coenzyme Q10 for two years resulted in significantly improved symptoms and survival [Mortensen].
  • A major factor affecting youthful ageing and longevity is staying free from degenerative disorders such as heart disease, diabetes, kidney disease, and liver disease [Mantle & Hargreaves].
  • CoQ10 supplementation and selenium supplementation help to keep us safe from these degenerative diseases through their activity in cellular energy generation, antioxidant protection of cells, and reduction of chronic low-grade inflammation [Mantle & Hargreaves].


Alehagen U, Johansson P, Björnstedt M, Rosén A & Dahlström U. (2013). 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. International Journal of Cardiology, 167(5), 1860-1866.

Alehagen U & Aaseth J. (2014). Selenium and Coenzyme Q10 interrelationship in cardiovascular diseases – A clinician’s point of view. Journal of Trace Elements in Medicine and Biology; 31:157-162.

Deichmann RE, Lavie CJ & Dornelles AC. (2012). Impact of Coenzyme Q-10 on parameters of cardiorespiratory fitness and muscle performance inolder athletes taking statins. Phys Sportsmed; 40:88-95.

Duberley KE, Abramov AY, Chalasani A, Heales SJ, Rahman S & Hargreaves IP. (2013).  Human neuronal Coenzyme Q10 deficiency results in global loss of mitochondrial respiratory chain activity, increased mitochondrial oxidative stress and reversal of ATP synthase activity. J Inherit Metab Dis; 36(1):63-73.

Judy WV. (2018). E-mail communication.

Kalén A, Appelkvist EL & Dallner G. (1989). Age-related changes in the lipid compositions of rat and human tissues. Lipids, 24(7):579–584.

Langsjoen, JO, Langsjoen AM & Langsjoen PH. (2005). A reduction in plasma Coenzyme Q10 (CoQ10) secondary to supplemental vitamin E. Los Angeles: 4th CoQ10 Conference of the International CoQ10 Association.

Littarru GP & Lambrechts P. (2011). Coenzyme Q10: multiple benefits in one ingredient; OCL (Oilseeds and Fats, Crops and Lipids); 18: 76-82.

López-Lluch G, Del Pozo-Cruz J, Sánchez-Cuesta A, Cortés-Rodríguez A B & Navas P. (2019). Bioavailability of Coenzyme Q10 supplements depends on carrier lipids and solubilization. Nutrition, 57, 133–140.

Mantle D & Hargreaves I. (2019). Coenzyme Q10 and degenerative disorders affecting longevity: an overview. Antioxidants (Basel); 8(2): 44.

Mortensen S A, Rosenfeldt F, Kumar A, Dolliner P, Filipiak K J, Pella D & Littarru GP (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.

Okuyama H, Langsjoen P H, Hamazaki T, Ogushi Y, Hama R, Kobayashi T & Uchino H. (2015). Statins stimulate atherosclerosis and heart failure: pharmacological mechanisms. Expert Review of Clinical Pharmacology, 8(2), 189-199.

Pelton R & LaValle JB. (2000). Nutritional Cost of Prescription Drugs. 1st ed. Englewood, CO: Morton Pub.

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

2 January 2020