m3-Huwentoxin IV (m3-HwTx-IV) is a potent Na V inhibitor with IC 50 s of 3.3, 6.8, 7.2, 8.4, 11.9 and 369 nM against hNa V 1.7, hNa V 1.6, hNa V 1.3, hNa V 1.1, hNa V 1.2 and hNa V 1.4, respectively in QPatch assay. m3-Huwentoxin IV dose-dependently suppresses spontaneous pain induced by the Na V 1.7 activator OD1 in a rodent pain model.