GSK-LSD1 2HCl is a selective inhibitor of LSD1 with IC50 value of 16 nM . Lysine (K) -specific demethylase 1A (LSD1) is a flavin-dependent histone demethylase that demethylates mono- and di-methylated lysines and plays an important role in oocyte growth, embryogenesis and tissue-specific differentiation. LSD1 plays a role in acute myeloid leukemia (AML). GSK-LSD1 2HCl irreversibly inhibited LSD1 with IC50 value of 16 nM and is > 1000 fold selective over LSD2, MAO-A and MAO-B, which were related to FAD utilizing enzymes. In cancer cell lines, GSK-LSD1 2HCl changed gene expression with average EC50 value < 5 nM and inhibited cells growth with average EC50 value < 5 nM. GSK-LSD1 2HCl (10 ?M) inhibited human recombinant dopamine transporter, 5-HT1A and 5-HT transporter by 39%, 49% and 74%, respectively. And no activity against other 55 recombinant receptors (GPCR, transporters, ion channels). GSK-LSD1 2HCl can be used as a chemical probe and a part of the SGC epigenetics .