Vagal nerve stimulation linked to lower final body weight versus control in pooled animal dataVagus Nerve Stimulation Linked to Lower Weight in Obesity

This meta-analysis synthesizes preclinical evidence on chronic electrical stimulation of the vagus nerve or a defined vagal branch, compared with control conditions, with final body weight as the primary outcome. Secondary outcomes included weekly body weight change, food intake, adiposity, metabolic outcomes, and safety.

Across the pooled studies, VNS was associated with lower final body weight than control conditions, with a Hedges' g of -1.07 (95% CI -1.43 to -0.72). Heterogeneity was moderate, with an I2 of 55.5%. The direction of effect favored lower weight with stimulation.

The authors note that included studies vary substantially in stimulation site, interface, stimulation parameters, species, diet condition, and reported outcomes. These differences are a key limitation and make it difficult to attribute the pooled effect to any single stimulation approach. Safety data, including adverse events, serious adverse events, discontinuations, and tolerability, were not reported. Follow-up duration, sample size, and population characteristics were also not reported. Funding and conflicts of interest were not reported.

The evidence is associative, and the authors caution that VNS was associated with lower final body weight rather than shown to cause it. Certainty of evidence was not reported. Practice relevance was not reported.

For clinicians, these findings are preclinical and do not establish a role for VNS in obesity management. The pooled effect is notable in magnitude but rests on heterogeneous animal work without safety reporting, so it should be read as hypothesis-generating rather than practice-changing.