Selumetinib is a potent, highly selective MEK1 inhibitor with IC50 of 14 nM, also inhibits ERK1/2 phosphorylation with IC50 of 10 nM, no inhibition to p38α, MKK6, EGFR, ErbB2, ERK2, B-Raf, etc.

Trametinib is a highly specific and potent MEK1/2 inhibitor with IC50 of 0.92 nM/1.8 nM, no inhibition of the kinase activities of c-Raf, B-Raf, ERK1/2.

U0126 ethanol is a highly selective inhibitor of MEK1/2 with IC50 of 0.07 μM/0.06 μM.

CI-1040 is an ATP non-competitive MEK1/2 inhibitor with IC50 of 17 nM, being 100-fold selective for MEK1/2 than MEK5.

PD98059 is a non-ATP competitive MEK inhibitor with IC50 of 2 μM, specifically inhibits MEK-1-mediated activation of MAPK and does not directly inhibit ERK1 or ERK2.

TAK-733 is a potent and selective MEK allosteric site inhibitor for MEK1 with IC50 of 3.2 nM, inactive to Abl1, AKT3, c-RAF, CamK1, CDK2, c-Met, etc.

SL327 is a cell-permeable vinylogous cyanamide that acts as a selective inhibitor of MEK-1 and MEK-2 (IC50 = 0.18 and 0.22 μM respectively).

Refametinib is a specific and non-ATP-competitive MEK 1/2 inhibitor with IC50 values of 19 and 47 nM, respectively.

GDC-0623 is a selective and ATP-uncompetitive MEK1 inhibitor with Ki value of 0.13 nM.

BI-847325 is a selective and orally bioavailable dual MEK/Aurora kinase inhibitor with IC50 of 3 nM (Xenopus laevis Aurora B), 25 nM (human Aurora A), 15 nM (human Aurora C), 25 nM (human MEK1), and 4 nM (human MEK2) respectively.

Cobimetinib is a potent and highly selective MEK1 inhibitor with IC50 of 4.2 nM, showing more than 100-fold selectively for MEK1 over MEK2 and showed no significant inhibition when tested against a panel of more than 100 of serine-threonine and tyrosine kinases.

Myricetin, a natural flavonoid isolated and purified from the root bark of Myrica cerifera L. with antioxidant and anti tumor properties, is an inhibitor of MEK1 activity and transformation of JB6 P+ mouse epidermal cells. It also inhibits PI3Kγ with Kd of 0.17 μM.