The effect of melatonin on the sexual function among postmenopausal women: A randomized placebo-controlled trial

Background: Menopause is associated with alterations in women's behaviors and sexual function. Altered sexual function can in turn causes serious health problems for women and negatively affect their marital relationships. Objective: This study aimed to investigate the effects of melatonin on the sexual function of postmenopausal women. Methods: This randomized double-blind placebo-controlled clinical trial was made in 2012–2013 on 240 postmenopausal women who aged 40–60 and referred to public obstetrics and gynecology clinics affiliated to Shiraz University of Medical Sciences, Shiraz, Iran. Participants were randomly divided into a melatonin and placebo group. Women in the melatonin and the placebo groups, respectively, received melatonin (3-mg tablets) and placebo for 3 consecutive months. Before and every 1 month during the intervention, participants' sexual function was assessed using Female Sexual Function Index. The repeated measures analysis of variance, the least significant difference, the independent sample t test, the Chi-square, and Fisher's exact tests were done for data analysis. Results: Sexual function mean score in the melatonin and placebo groups significantly increased from 12.49 ± 7.07 to 20.72 ± 8.57 and from 12.11 ± 7.82 to 15.55 ± 9.06, respectively. Yet, the amount of increase in the melatonin group was significantly higher than the placebo group. Moreover, there were significant differences between the groups regarding the variations of sexual function mean score across the four assessment points (P < 0.001). In addition, except for the baseline assessment point, the mean score of sexual function in the melatonin group was significantly greater than the control group at all other assessment points (P < 0.05). Conclusion: Melatonin significantly improves sexual function among postmenopausal women.