The effects of melatonin supplementation on obesity and glycemic indices in women with overweight and obesity: a systematic review and meta-analysis of randomized controlled trials
Abstract
Objective: Obesity in women is closely linked to metabolic and circadian disruption. Melatonin has emerged as a potential adjunct therapy for improving obesity-related outcomes, yet evidence specific to women has been inconsistent. This systematic review and meta-analysis evaluated the effects of melatonin supplementation on anthropometric and glycemic indices in women with overweight and obesity.
Methods: PubMed/MEDLINE, Web of Science, Scopus, Embase, and the Cochrane Library (CENTRAL), were searched through April 2025. Random-effects models generated weighted mean differences (WMDs) with 95% confidence intervals (CIs).
Results: Fourteen trials were included. Melatonin produced a significant reduction in body mass index (BMI) (WMD: - 1.03 kg/m²; 95% CI: - 2.23 to - 0.16; p < 0.001), with stronger effects in studies ≥ 12 weeks, using ≥ 6 mg/day, or involving participants with baseline BMI ≥ 30 kg/m². Melatonin significantly improved glycemic markers: fasting blood sugar (WMD: - 1.89 mg/dL; 95% CI: - 3.56 to - 0.22; p = 0.026), insulin (WMD: - 2.05 uIU/mL; 95% CI: - 3.69 to - 0.40; p = 0.015), and HOMA-IR (WMD: - 0.54; 95% CI: - 1.04 to - 0.03; p = 0.036). However, melatonin supplementation did not significantly affect body weight (WMD: - 0.34 kg; 95% CI: - 2.34 to 1.66; p = 0.737) or waist circumference (WMD: - 0.66 cm; 95% CI: - 3.75 to 2.43; p = 0.676).
Conclusion: Melatonin supplementation modestly reduces BMI and significantly improves fasting glucose, insulin levels,…
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