Diabetes is a major health problem world-wide. More than 90% of patients with diabetes have type 2 diabetes in which case the pancreas does not make enough insulin or the insulin that the pancreas makes is not effective. Patients with type 2 diabetes are at higher risk of developing heart disease, hypertension, and stroke. Oxidative stress is a known factor in the development and progression of type 2 diabetes. Coenzyme Q10 is an important fat-soluble antioxidant that can scavenge harmful free radicals and protect the cells from oxidative damage.

Individuals with type 2 diabetes are known to have considerably lower plasma/serum Coenzyme Q10 concentrations than do individuals who do not have diabetes [Zhang].

A 2018 meta-analysis and systematic review of the research literature indicates that Coenzyme Q10 supplementation improves glycemic control and increases HDL-cholesterol in individuals with type 2 diabetes [Zhang].

CoQ10 Supplementation and Glycemic Control

The results of the meta-analysis, drawn from an aggregated 13 clinical trials enrolling 795 patients with type 2 diabetes, show that the CoQ10 supplementation significantly decreased HbA1c (p=0.03) and fasting glucose (p=0.005).

Note: HbA1c is a measurement of glycated hemoglobin (hemoglobin bound to glucose). Doctors use HbA1c measurements to get an idea of what a patient’s average blood sugar levels have been over a period of weeks or months. The higher the HbA1c is, the greater the risk of complications related to diabetes.

Coenzyme Q10 Supplementation and Insulin Resistance

In the meta-analysis, the Coenzyme Q10 supplementation did not affect fasting insulin levels or HOMA-IR insulin resistance levels.

Note: Insulin is a hormone that helps to regulate the levels of sugar (glucose) in the blood.  HOMA-IR test results show how sensitive or resistant a patient is to the effects of insulin.

The researchers explain that the lack of an effect on fasting insulin and on insulin resistance is an indication that Coenzyme Q10 supplementation is a treatment option that may be safe to use with patients with type 2 diabetes [Zhang]. Patients with type 2 diabetes can use Coenzyme Q10 supplements for their heart health benefits without worrying that the extra Coenzyme Q10 will increase insulin resistance.

CoQ10 Supplementation and Cholesterol Levels

Coenzyme Q10 supplementation was associated, in this meta-analysis, with a statistically significant increase in HDL-C, the so-called good cholesterol. Higher levels of HDL-C are thought to be a good thing [Zhang].

The aggregated data from the 8 studies (out of 13) that addressed the issue of LDL-C, the so-called bad cholesterol, did not show any statistically significant reduction of LDL-cholesterol through the use of Coenzyme Q10 supplements [Zhang].

Coenzyme Q10 Supplementation and Diabetes Patients taking Statin Medications

Statin medications reduce cholesterol levels and reduce the risk of heart attack.  However, in the same period that statin medications have been prescribed, there has also been a significant increase in the risk of heart failure. Professor Okuyama and his colleagues explain that statin medications inhibit not only the body’s synthesis of cholesterol but also its synthesis of Coenzyme Q10.  And, if that were not bad enough, the statin medications inhibit the incorporation of selenium into the antioxidant selenoproteins, inhibit the synthesis of vitamin K2, and are associated with reduced levels of the enzymatic antioxidants superoxide dismutase and catalase [Okuyama].

Because cholesterol and Coenzyme Q10 are synthesized in the same biochemical pathway, statin medications block the body’s production of Coenzyme Q10.  It is practically impossible to make up for the loss of CoQ10 by eating more or eating more wisely.  Coenzyme Q10 supplementation is, accordingly, essential for patients with type 2 diabetes who are taking statin medications [Zhang].

Moreover, statin medications themselves are thought to increase the risk of developing type 2 diabetes [Mantle].

Dr. William V. Judy, SIBR Research Institute, has seen that Coenzyme Q10 supplementation is necessary as an adjunctive treatment for elderly diabetes patients with very low blood CoQ10 concentrations. Diabetes patients with blood levels below 0.35 micrograms per milliliter will not be able to maintain good blood glucose control, not even with the strongest drug therapy. They must raise their blood CoQ10 concentrations.

Safety of Coenzyme Q10 Supplementation for Patients with Type 2 Diabetes

None of the 13 study publications analyzed in the meta-analysis reported any adverse effects of taking Coenzyme Q10 supplements.

This result alone is not a guarantee of absolute safety, but Coenzyme Q10 generally has been shown to be well-tolerated with no serious adverse effects.  There are no known toxic effects associated with Coenzyme Q10.  There are no reports of Coenzyme Q10 overdosing in research literature extending back 50 years [Mantle].

Possible Limitations of the Meta-analysis of Coenzyme Q10 and Diabetes Studies

The researchers doing the meta-analysis pointed to the following possible limitations of the analysis [Zhang]:

  • The sample sizes in the studies were small.
  • The characteristics of the study participants were heterogeneous.
  • The duration of the Coenzyme Q10 treatment was relatively short, ranging from 3 to 6 months.
  • The effect of longer-term Coenzyme Q10 supplementation on patients with type 2 diabetes has not been tested and documented.

Conclusion: CoQ10 and Type 2 Diabetes Patients

It cannot be emphasized enough that not all Coenzyme Q10 supplements are equally good.

CoQ10 supplements vary in their formulations and, accordingly, in their absorption and bio-availability [Lopez-Lluch].

A cheaper Coenzyme Q10 supplement may possibly have a decent formulation and give a decent bio-availability, but it is surely wisest to stick to CoQ10 supplements with documented absorption and bio-availability and documented significant health effects in clinical studies [Alehagen; Mortensen].


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.

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. (2017). Coenzyme Q10 supplementation for diabetes and its complications: a review. The British Journal of Diabetes, 17(4): 145-48.

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.

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.

Zhang, S.-Y., Yang, K.-L., Zeng, L.-T., Wu, X.-H., & Huang, H.-Y. (2018). Effectiveness of Coenzyme Q10 Supplementation for Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis. International Journal Of Endocrinology, 2018, 6484839.

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