The objectives of this study were to investigate the effects of cinnamon supplementation on glycemic indices, serum lipids and adiponectin in patients with polycystic ovary syndrome (PCOS).

This double-blind randomized controlled clinical trial was conducted on 84 overweight or obese PCOS patients. Subjects in cinnamon (n=42) and placebo (n=42) groups were given 3 cinnamon capsules (each one contained 500 mg cinnamon) or placebo daily for 8 weeks. Fasting blood samples, anthropometric measurements and dietary intake data were collected at the baseline and at the end of the trial. Data were analyzed by independent t test, paired t test and analysis of covariance.

Cinnamon significantly decreased serum fasting blood glucose, insulin, homeostatic model assessment for insulin resistance, total cholesterol and low-density lipoprotein cholesterol and weight and increased high-density lipoprotein cholesterol compared with placebo (all p<0.05). Serum triglyceride and body mass index significantly decreased in the cinnamon group, in comparison with baseline values (p=0.001 and p=0.002, respectively). No significant changes were seen in serum adiponectin in either group.

Short term supplementation of cinnamon had some favourable effects on metabolic risk factors of women with PCOS and may be useful in management of PCOS complications.