SB 415286 is a potent and selective ATP-competitive inhibitor of glycogen synthase kinase-3 (GSK-3), exhibiting IC50 values of 78 nM and 31 nM for GSK-3alpha and GSK-3beta, respectively. This cell-permeable compound is widely used in vitro and in vivo to investigate GSK-3s role in Wnt/beta-catenin signaling, neurodegenerative diseases, and glucose metabolism.