Cinnamon extract effects on insulin resistance, metabolic factors, and menstrual cyclicity of women with polycystic ovary syndrome: A systematic review and meta-analysis

Background: Cinnamon is a herbal medicine that is supposed to improve the metabolic disorder polycystic ovary syndrome (PCOS), but there is still no data about the effectiveness and efficacy of this herbal medicine for the metabolic parameters of PCOS. This study aims to systematically evaluate the effects of cinnamon extract on improving insulin resistance, lipid profile and regularity of menstruation in PCOS women. Methods: This is a systematic review and meta-analysis of randomized controlled trials (RCTs) studies. We searched the MEDLINE, Cochrane, Google Scholar, and PubMed databases to identify relevant studies using cinnamon extract effects on insulin resistance, metabolic factors, and menstrual cyclicity of PCOS women. Results: Five RCTs consisting of 206 women were included in the meta-analysis. Significant differences were found in fasting blood glucose (FBG) (mean difference (MD)= -4.8 mg/dL, 95% CI: -8.04 to -1.57, p=0.004; 143 participants), High-Density Lipoprotein (HDL-cholesterol, HDL-C) (MD= -27.24 mg/dL, 95% CI: -32.62 to -21.85, p< 0.00001; 143 participants, Insulin level (MD = -2.20 mIU/dL, 95% CI: -4.17 to -0.23, p=0.03; 143 participants), and menstrual cyclicity in six months (MD= 2.28, 95% CI: 1.83 to 2.73, p< 0.00001; 33 participants) were obtained. Conclusion: Cinnamon can be a potential supplementary therapy agent for PCOS women as it improves fasting blood glucose, insulin level, HDL–cholesterol and menstrual cyclicity in PCOS women.