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

May 14, 2026Diabetology & metabolic syndrome

Melatonin supplements and their impact on weight and blood sugar in overweight and obese women

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗OA ↗

Abstract

Melatonin supplementation resulted in a significant reduction in body mass index (BMI) by 1.03 kg/m² in women with overweight and obesity.

Among studies lasting 12 weeks or longer and using 6 mg/day or more, the reduction in BMI was more pronounced.
Fasting blood sugar levels decreased by 1.89 mg/dL, indicating improved glycemic control.
Insulin levels were reduced by 2.05 uIU/mL, suggesting better insulin sensitivity.
The homeostasis model assessment of insulin resistance (HOMA-IR) showed a decline of 0.54, indicating improved insulin resistance.
No significant changes were observed in overall body weight or waist circumference.

AI simplified

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, and insulin resistance in women with overweight and obesity. No significant effects were observed on body weight or waist circumference. These findings suggest that melatonin may serve as a complementary strategy for improving metabolic parameters, particularly glycemic control.

Full Text

Full text is available at the source.

View full text (HTML) ↗

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

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief