2-MNG (2-Mercaptonicotinoyl glycine) is an inhibitor for melanogenesis with an average IC 50 of 49.5μM in normal human melanocytes. 2-MNG binds to melanin precursors, prevents the incorporation into growing melanin, and thereby inhibits the synthesis of eumelanin and pheomelanin. 2-MNG can be used in research about skin pigmentation.