MLR-1023 is an allosteric activator of Lyn kinase (EC50 = 63 nM). It has no significant activity against a panel of related kinases. MLR-1023 is orally bioavailable and reduces blood glucose levels in mice subjected to an oral glucose tolerance test. This effect is insulin-dependent, with MLR-1023 increasing insulin receptor sensitivity. MLR-1023 produces a dose-dependent and durable glucose-lowering effect in chronically treated db/db mice without causing weight gain.