Purity >98% by NMR, TLC. A83-01 is a potent and selective ALK4, 5 and 7 inhibitor. IC50 = 45, 12 and 7.5 nM respectively. Prevents phosphorylation of Smad2/3 and growth inhibition induced by TGFb. Inhibits differentiation of rat induced pluripotent stem cells and increases clonal expansion efficiency. Together with AMI-5, A83-01 enabled Oct4-induced reprogramming of mouse embryonic fibroblasts. Cell permeable. Active in vivo.