WP-L6 was developed as a sub-nanomolar inhibitor of Porcupine, the enzyme that catalyzes the palmitoylation of Wnt proteins. In HEK293 cells, IWP-L6 is found to significantly inhibit the phosphorylation of dishevelled 2 (Dvl2). IWP-L6 has good stability in human plasma but weaker stability in rat and mouse plasma. In vivo assay shows that IWP-L6 is quite active in zebrafish. It blocks the regeneration of the tailfin effectively. It also shows inhibition of posterior axis formation at low micromolar concentrations. Additionally, in cultured mouse embryonic kidneys, 10 nM IWP-L6 can significantly reduce branching morphogenesis while 50 nM IWP-L6 completely blocks Wnt signaling.