Effect of Auricular Acupoint Stimulation on Weight in Adults with Overweight or Obesity: A Systematic Review and Meta-Analysis

Objectives: To systematically evaluate the effectiveness of auricular acupoint stimulation for weight reduction and metabolic outcomes in adults with overweight or obesity. Design: Systematic review and meta-analysis of randomized controlled trials. Methods: Six electronic databases (PubMed, Cochrane Library, Embase, CINAHL, Web of Science, and Scopus) were searched from inception to 5 February 2026. The primary outcome was body weight; secondary outcomes included body mass index, waist circumference, and metabolic markers. Methodological quality was assessed using the Joanna Briggs Institute checklist. For the primary outcome, a multilevel random-effects model was fitted using restricted maximum likelihood estimation, with small-sample-adjusted cluster-robust variance estimation (CR2) to account for dependent comparisons within studies. Subgroup analyses, meta-regression, sensitivity analyses, and publication bias assessments were also conducted. Results: A total of 20 studies were included in the systematic review, of which 14 contributed 15 comparisons to the primary meta-analysis of post-intervention body weight. The pooled effect was Hedges' g = -0.21 (95% CI: -0.42 to -0.01, p = 0.043). Heterogeneity estimates were I² = 46.6% (95% CI: 8.1-76.8%) and τ² = 0.06 (95% CI: 0.01-0.21), and the 95% prediction interval ranged from -0.71 to 0.29. Formal subgroup tests and univariate meta-regression yielded p values below 0.05 for publication year, funding status, and quality appraisal score. Sensitivity analyses produced estimates in the same direction, although the confidence interval included the null value in some leave-one-out analyses. Conclusions: The pooled estimate suggested a small reduction in post-intervention body weight with auricular acupoint stimulation, but the prediction interval included the null value, indicating uncertainty in the effect across comparable settings. Further well-designed trials with standardized intervention protocols are needed to clarify the magnitude and consistency of the effect.