Hormonal and Metabolic Effects of Coenzyme Q10 and/or Vitamin E in Patients With Polycystic Ovary Syndrome

J Clin Endocrinol Metab. 2019 Feb 1;104(2):319-327. doi: 10.1210/jc.2018-01221.


Context: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-age women. The hormonal and metabolic effects of coenzyme Q10 (CoQ10) and/or vitamin E in patients with PCOS have not been studied, to our knowledge.

Objective: To evaluate the effects of CoQ10 and/or vitamin E on glucose homeostasis parameters and reproductive hormones in women with PCOS.

Design, setting, participants: Randomized, double-blind, placebo-controlled clinical trial among 86 women with PCOS.

Intervention: CoQ10 or vitamin E or combination for 8 weeks.

Main outcome measures: Glucose homeostasis parameters and sex hormone concentrations.

Results: After adjustment for potential confounders, supplementation with CoQ10 alone or in combination with vitamin E, compared with placebo, had significant effects on fasting blood sugar (FBS); vitamin E's effect on FBS was not significant. A significant reduction in homeostasis model assessment of insulin resistance (HOMA-IR) was observed in the CoQ10 and combined groups. CoQ10, vitamin E, and cosupplementation led to decreased serum total testosterone levels (P < 0.001) compared with those of the placebo group. CoQ10 supplementation in combination with vitamin E significantly improved in sex hormone-binding globulin (SHBG) levels compared with other groups (P = 0.008). Linear regression analysis revealed that changes in FBS, insulin, and HOMA-IR were predictors of change in free androgen index (P < 0.05).

Conclusion: CoQ10 with or without vitamin E supplementation among women with PCOS had beneficial effects on serum FBS and insulin levels, as well as HOMA-IR and total testosterone levels. However, only cosupplementation affected SHBG concentrations.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anthropometry / methods
  • Blood Glucose / metabolism
  • Diet / statistics & numerical data
  • Dietary Supplements
  • Double-Blind Method
  • Drug Therapy, Combination
  • Female
  • Gonadal Steroid Hormones / blood
  • Humans
  • Insulin / blood
  • Insulin Resistance / physiology
  • Polycystic Ovary Syndrome / blood
  • Polycystic Ovary Syndrome / drug therapy*
  • Ubiquinone / analogs & derivatives*
  • Ubiquinone / therapeutic use
  • Vitamin E / therapeutic use*


  • Blood Glucose
  • Gonadal Steroid Hormones
  • Insulin
  • Ubiquinone
  • Vitamin E
  • coenzyme Q10

Associated data

  • IRCT/IRCT201610193140N18