Melatonin Treatment May Be Able to Restore Menstrual Cyclicity in Women With PCOS: A Pilot Study

Reprod Sci. 2018 Feb;25(2):269-275. doi: 10.1177/1933719117711262. Epub 2017 May 31.


The objective of the study was to investigate the effects of 6 months of melatonin administration on clinical, endocrine, and metabolic features of women affected by polycystic ovary syndrome (PCOS). This is a prospective cohort study including 40 normal-weight women with PCOS between January and September 2016, enrolled in an academic research environment. Ultrasonographic pelvic examinations, hirsutism score evaluation, hormonal profile assays, oral glucose tolerance test, and lipid profile at baseline and after 6 months of melatonin administration were performed. Melatonin treatment significantly decreased androgens levels (free androgen index: P < .05; testosterone: P < .01; 17 hydroxyprogesterone: P < .01). Follicle-stimulating hormone levels significantly raised ( P < .01), and anti-Mullerian hormone serum levels significantly dropped after 6 months of melatonin treatment ( P < .01). No significant changes occurred in glucoinsulinemic and lipid parameters after treatment except a significant decrease of low-density lipoprotein cholesterol. Almost 95% of participants experienced an amelioration of menstrual cycles. Until now, only few data have been published about the role of melatonin in women with PCOS. This is the first study focused on the effects of exogenous oral melatonin administration on the clinical, endocrine, and metabolic characteristics of patients with PCOS. After 6 months of treatment, melatonin seems to improve menstrual irregularities and biochemical hyperandrogenism in women with PCOS through a direct, insulin-independent effect on the ovary. Based on our results, melatonin could be considered a potential future therapeutic agent for women affected by PCOS.

Keywords: PCOS; insulin; melatonin; menstrual irregularities.

MeSH terms

  • 17-alpha-Hydroxyprogesterone / blood
  • Adult
  • Blood Glucose
  • Female
  • Glucose Tolerance Test
  • Hirsutism / blood
  • Hirsutism / diagnostic imaging
  • Hirsutism / drug therapy*
  • Humans
  • Hyperandrogenism / blood
  • Hyperandrogenism / diagnostic imaging
  • Hyperandrogenism / drug therapy*
  • Lipids / blood
  • Melatonin / pharmacology*
  • Melatonin / therapeutic use
  • Menstrual Cycle / blood
  • Menstrual Cycle / drug effects*
  • Polycystic Ovary Syndrome / blood
  • Polycystic Ovary Syndrome / diagnostic imaging
  • Polycystic Ovary Syndrome / drug therapy*
  • Prospective Studies
  • Testosterone / blood
  • Ultrasonography
  • Young Adult


  • Blood Glucose
  • Lipids
  • Testosterone
  • 17-alpha-Hydroxyprogesterone
  • Melatonin