NNMT-IN-3 (compound 14) is a potent and selective nicotinamide N-methyltransferase NNMT inhibitor with IC50 values of 1.1 nM and 0.4 μM in cell-free and cell-based assays, respectively. NNMT-IN-3 can be used to research obesity, type 2 diabetes, alcohol-related liver disease, cancer, sarcopenia and so on.