Delpino FM, et al. - Via this systematic review and meta-analysis, researchers analyzed randomized clinical trials that assessed impacts of melatonin supplementation, vs placebo, on diabetes parameters among humans. They explored Pubmed, LILACS, Scielo, Scopus, Web of Science, Cochrane, and Embase to identify the relevant studies. They excluded non-randomized clinical trials, observation studies, and animal models. Overall, 16 studies were analyzed, of which 56% demonstrated that melatonin supplementation was beneficial for diabetes parameters when compared with placebo. In meta-analysis, significant results for fasting blood glucose, glycated hemoglobin, and for insulin resistance were obtained. Overall, findings demonstrate the usefulness of melatonin supplementation, vs placebo, for reducing diabetes parameters.