Melatonin supplementation and anthropometric indicators of obesity: A systematic review and meta-analysis

Abstract Objective According to in vivo and in vitro studies, melatonin appears to be a potential supplement for obesity reduction. The aim of this study was to review the literature on randomized clinical trials that evaluated the effects of melatonin supplementation on anthropometric indicators of obesity in humans. Methods We conducted a systematic review with meta-analysis in the following databases: Pubmed, LILACS, Scielo, Scopus, Web of Science, Cochrane, and Embase. We included studies that evaluated melatonin supplementation's effects, compared with placebo, on anthropometric measures, including body weight, body mass index (BMI), and waist circumference, in people ≥18 y of age. This systematic review and meta-analysis were registered on PROSPERO: CRD42021241079. Results Of the 23 studies included, 11 showed significant results from melatonin supplementation on weight loss, BMI, or waist circumference, compared with placebo. In the meta-analysis, melatonin supplementation significantly reduced body weight (standardized mean difference, –0.48; 95% confidence interval, –0.94 to –0.02; P =  Conclusion The results demonstrated that melatonin supplementation was responsible for significantly reducing body weight. More studies are needed before melatonin can be recommended for weight loss.