Insulin resistance improvement by cinnamon powder in polycystic ovary syndrome: A randomized double‐blind placebo controlled clinical trial

Our aim is to assess the effect of cinnamon powder capsules on insulin resistance, anthropometric measurements, glucose and lipid profiles, and androgens of women with polycystic ovarian syndrome (PCOS). Out of 80 women that were diagnosed as PCOS by Rotterdam Criteria, 66 were enrolled in this randomized double‐blind placebo‐controlled clinical trial. All of the PCOS women were taking medroxy progesterone acetate 10 mg/day for the last 10 days of their menstrual cycles. The cases were randomly allocated to 2 groups. The women in the first group were treated by cinnamon powder capsules 1.5 g/day in 3 divided doses for 12 weeks and the second group by similar placebo capsules. Anthropometric measurements, fasting blood sugar, fasting insulin, blood glucose 2 hr after taking 75 g oral glucose, HbA1c, testosterone, dehydroepiandrosterone sulphate, homeostatic model assessment for insulin resistance, triglyceride, and cholesterol (low‐density lipoprotein, high‐density lipoprotein, and total) before and after the intervention were evaluated and compared as outcome measures. Fasting insulin (p = .024) and homeostatic model assessment for insulin resistance (p = .014) were reduced after 12 weeks in the cinnamon group compared with the placebo. There was also a significant decrease in low‐density lipoprotein in cinnamon group (p = .004) as compared with baseline that caused significant difference with placebo (p = .049). However, changes in other outcome measurements did not lead to statistically significant difference with placebo. The present results suggest that complementary supplementation of cinnamon significantly reduced fasting insulin and insulin resistance in women with PCOS.