We found no significant associations between GLP1-RA-induced weight loss and polygenic scores for body mass index or type 2 diabetes, nor with missense variants in GLP1R. A higher body mass index polygenic score was modestly linked to lower weight loss after BS (+0.7% per s.d., P = 1.24 × 10−4), but the effect attenuated in sensitivity analyses. This evidence concerns the gene GCG and type 2 diabetes mellitus.