m3-Huwentoxin IV (#STH-102) is a highly pure, synthetic, and biologically active peptide toxin. It is a mutated variant of Huwentoxin IV, a peptide toxin originally isolated from the Chinese bird-eating spider Haplopelma schmitdi venom. m3-Huwentoxin IV is a significantly more potent NaV1.7 channel bocker, displaying an IC50 value of 0.4 nM.