Documented safety of Coenzyme Q10 supplementation

Yes, the raw material Coenzyme Q10 and the manufactured Coenzyme Q10 supplements are documented as safe and well-tolerated. However, the efficacy of the various CoQ10 supplements available on the US market varies considerably. It is wise to purchase a CoQ10 supplement that is supported by scientific documentation. For example, the CoQ10 supplement used in the Q-Symbio study, the KiSel-10 study, and the Gulf War Illness study has been evaluated in randomized controlled clinical trials. There is documented evidence that it is effective.

The nutritional supplement Coenzyme Q10 is non-toxic and without any noteworthy safety concerns [Hathcock; Ikematsu].

  • Coenzyme Q10 is very well-tolerated, and it does not cause any notable adverse effects at daily dosages as high as 1200 milligrams per day [Hathcock].
  • Studies of healthy individuals and studies of individuals with kidney impairment and liver impairment have not shown any potential for an adverse effect of CoQ10 supplementation on the kidneys or on the liver [Watson; Mabuchi; Farhangi].
  • A randomized, double-blind, placebo-controlled study enrolling healthy study participants showed no dose-related changes in hematology, blood biochemistry, and urinalysis [Ikematsu].
  • Moreover, plasma CoQ10 concentrations after an 8-month period of withdrawal from CoQ10 supplementation were nearly the same as before the supplementation [Ikematsu].

Importance of CoQ10 nutritional supplements

Note: Coenzyme Q10 is arguably the most important nutritional supplement for healthy individuals above the age of 40.  Cellular bio-synthesis of CoQ10 begins to slow down once we are past our 20s and lessens then with increasing age [Kalén].

  • CoQ10 in its oxidized form (ubiquinone form) is an essential co-factor in the process of cellular energy production.
  • CoQ10 in its reduced form (ubiquinol form) is an important fat-soluble antioxidant, protecting the cells against free radical damage.
  • CoQ10 is associated with significant improvement in endothelial function [Gao].
  • Coenzyme Q10 is a necessary supplement for patients taking statin medications as the use of statin medications inhibits the bio-synthesis of CoQ10 [Okuyama].

Daily supplemental dosages of CoQ10

  • A typical daily nutritional supplement dosage is 100 milligrams per day.
  • A typical therapeutic dosage for adjuvant treatment of chronic heart failure is 300 milligrams a day, taken as 3 times 100 milligrams with meals [Mortensen].
  • Coenzyme Q10 dosages of 300 milligrams per day have proven efficacy as an adjunctive treatment for chronic heart failure patients and patients with high blood pressure [Mortensen; Rosenfeldt].

No reports of potential overdose of CoQ10

There are no reports in the bio-medical literature of any potential for an acute intoxicating overdose in humans.

  • The estimated observed safe level of daily CoQ10 intake for adults is set at 1200 milligrams per day [Hathcock].
  • The few adverse effects reported in conjunction with Coenzyme Q10 supplementation – primarily nausea and other minor gastrointestinal effects – have been no more common at 1200 milligrams per day than at 60 milligrams per day [Hathcock].
  • 1200 milligrams per day is four times the daily amount of CoQ10 supplementation that resulted in the significantly improved symptoms and survival of chronic heart failure patients [Mortensen] and six times the amount that helped reduce the risk of death from heart disease in healthy senior citizens [Alehagen].
  • The highest daily dose of CoQ10 that has been investigated is 3600 milligrams per day for 12 weeks [Hyson].
Dr. William Judy, SIBR Research Institute, has seen a very low incidence of mild adverse effects of Coenzyme Q10 supplementation in his 30-year management of heart failure study.  Moreover, it is not clear that the few adverse effects that get reported are caused by the CoQ10 supplement. The same adverse effects occur in patients taking the placebo preparation.

Very low rate of mild adverse effects of CoQ10 supplementation

A 2003 survey of 13 randomized controlled studies of CoQ10 supplementation of heart failure patients as well as of open-label studies in heart failure showed that 200 milligrams of CoQ10 per day for 6–12 months and 100 milligrams per day for up to 6 years resulted in no major side effects.  The survey showed a rate of mild adverse effects at less than one-half of one percent [Mortensen].

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The safety of Coenzyme Q10 supplements

Healthy eating
To stay as young as we can as late in life as possible, we need to eat right, exercise, and get a good night’s sleep. Then, a well-tested and well-documented Coenzyme Q10 supplement should be right at the top of the list of nutritional supplements that we take. As we get older, our bodies produce less and less Coenzyme Q10, and we cannot make up the difference through food alone.

Coenzyme Q10 supplements are so safe that I have not spent much time writing about their safety.  It would not be much of an exaggeration to say that Coenzyme Q10 supplements are as safe as water.  In fact, in study after study, there is no difference in side effects between the Coenzyme Q10 active treatment group and the placebo control group. 

We need a good Coenzyme Q10 status.  There are two primary reasons why Coenzyme Q10 supplementation provides heart health benefits:

  • Coenzyme Q10 is essential to the process of cellular energy production.
  • Coenzyme Q10 works as an antioxidant to protect the cells against the damage caused by harmful free radicals.

Let’s look at some of the studies.

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