Quantitative Evaluation of the Temporal Effects of Herbal drugs on Weight Loss: A Model-Based Meta-Analysis

AbstractBackground: The global obesity crisis demands effective and accessible weight management solutions. While herbal medicines are popular, their efficacy remains unclear due to the limitations of traditional meta-analyses relying on static endpoints. This study aimed to provide a dynamic evaluation of the time-course of weight loss for various natural products.Methods: A systematic review of PubMed and Embase identified randomized, placebo-controlled trials of herbal products for weight loss in overweight or obese adults. A model-based meta-analysis (MBMA) using an Emax model quantified the placebo-subtracted weight-loss effects over time, with simulated Orlistat (60 mg) as a reference comparator.Results: From 58 eligible studies (3,259 subjects), only tea (Camellia sinensis) and Ephedra-containing medications provided sufficient data for robust modeling. The model estimated a time to 50% maximal effect (ET50) of 5.2 weeks. The maximum weight loss (Emax) was -0.71 kg (95% CI: -1.04, -0.11) for tea and -3.33 kg (95% CI: -3.68, -1.81) for Ephedra. At 24 weeks, the typical effect of Ephedra (-2.73 kg) surpassed that of simulated Orlistat (-1.86 kg), while tea's effect was inferior.Conclusion: This MBMA quantified the modest weight-loss effect of tea and found that while the efficacy of Ephedra is comparable to that of Orlistat, its established safety risks preclude its clinical application. However, the evidence for most other herbal agents is low quality and lacks longitudinal data for definitive assessment, underscoring an urgent need for higher-quality trials.