WS6 is a compound that stimulates the proliferation of pancreatic β cells in rodent and human primary islets (ECmax = 200 and 400 nM, respectively, over four days). It promotes β cell growth in vivo, increasing β cell mass and normalizing blood glucose in the RIP-DTA mouse model of β cell ablation. WS6 also stimulates α cell proliferation in human pancreatic islets. WS6 appears to act by inhibiting IKKε and blocking the ability of EBP1 to suppress E2F-medtiated transcription.