SB431542 is a potent and selective inhibitor of ALK5 with IC50 of 94 nM, 100-fold selective for ALK5 than p38 MAPK and other kinases.

LY2157299 is a potent TGFβ receptor I (TβRI) inhibitor with IC50 of 56 nM in a cell-free assay.

LY2109761 is a selective TGF-β receptor type I/II (TβRI/II) dual inhibitor with Ki of 38 nM and 300 nM, respectively and is shown to negatively affect the phosphorylation of Smad2.

SB-525334 is a potent and selective inhibitor of TGFβ receptor I (ALK5) with IC50 of 14.3 nM, is 4-fold less potent to ALK4 than ALK5 and inactive to ALK2, 3, and 6.

SB505124 is an inhibitor of TGFβ receptor for ALK4 (IC50 = 129 nM) and ALK5 (IC50 = 47 nM). It can also inhibit ALK7.

GW788388 is a selective ALK5 inhibitor with IC50 of 18 nM and also inhibits TGF-β type II receptor and activin type II receptor.

LY364947 is a potent ATP-competitive inhibitor of TGFβR-I with IC50 of 59 nM, exhibits 7-fold selectivity over TGFβR-II.

RepSox is a potent and selective inhibitor of the TGFβR-1/ALK5 with IC50 of 23 nM and 4 nM for ATP binding to ALK5 and ALK5 autophosphorylation, respectively.

SD-208 is a potent, orally active ATP-competitive transforming growth factor-β receptor 1 (TGF-βRI) inhibitor (IC50= 49 nM) and displays > 100-fold and > 17-fold selectivity over TGF-βRII and other common kinases respectively.

EW-7197 is a selective inhibitor of TGF-β receptor ALK4 and ALK5 with IC50s of 13 nM and 11 nM.

LDN-212854 is an inhibitor of BMP and can inhibit ALK2 with IC50 of 1.3 nM. It is used to prevent heterotopic ossification.