Impact of Melatonin Supplementation on Glycemic Parameters in Patients with Type 2 Diabetes: A Systematic Review and Meta-analysis

Abstract

BACKGROUND: Several previous studies indicated that melatonin supplementation may positively affect glycemic control in patients with diabetes. However, research on the influence of melatonin supplementation on glycemic parameters remains inconclusive. Therefore, this study aimed to assess the impacts of melatonin supplementation on glycemic parameters in type 2 diabetes by conducting a meta-analysis. METHODS: PubMed/Medline, Scopus, and Web of Science were comprehensively searched until July 2024 to find eligible randomized clinical trials (RCTs). The overall effect sizes were estimated by using the randomeffect model and presented as weighted mean differences (WMD) with a 95 confidence interval (CI). Furthermore, the heterogeneity among the included trials was assessed by performing the Cochran Q test and interpreted based on the I(2) statistic. RESULTS: Of the 1361 papers, eight eligible RCTs were included in this meta-analysis. Our findings indicated that melatonin supplementation significantly decreased fasting blood glucose (WMD = -12.65 mg/dl; 95 CI: -20.38, -4.92; P = 0.001), insulin (WMD = -2.30 muU/ml; 95 CI: -3.20, -1.40; P < 0.001), hemoglobin A1c (WMD = -0.79 ; 95 CI: -1.28, -0.29; P = 0.002), and HOMA-IR (WMD, -0.83; 95 CI: -1.59 to - 0.07; P = 0.03). CONCLUSION: According to the results of the current meta-analysis, persons with type 2 diabetes who supplement with melatonin had improved glycemic control. It looks that supplementing with melatonin at a dose exceeding 6 mg daily for over a period of 12 weeks may be more successful than other forms of intervention. Nevertheless, further research with larger sample sizes is necessary to draw definitive conclusions.