GW 9508 is a potent and selective agonist for the free fatty acid receptor FFA1 (GPR40) with pEC₅₀ of 7.32; 100-fold selective against GPR120. Inactive against a range of other GPCRs, kinases, proteases, integrins and PPARs. Potentiates glucose-stimulated insulin secretion in MIN6 cells (pEC₅₀ = 6.14).