To confirm the potential role of Cxxc5 as a target for the treatment of obesity and diabetes, we orally administered KY19334, a small molecule that specifically interferes with the cytosolic function of CXXC5 as a negative regulator of the Wnt/β‐catenin pathway by inhibition of the CXXC5‐Dvl protein–protein interaction (PPI),16 and examined its effects on metabolism. This evidence concerns the gene CXXC5 and obesity due to melanocortin 4 receptor deficiency.