CBB1007 HCl is a cell-permeable amidino-guanidinium compound identified as a potent, reversible, and substrate-competitive inhibitor of LSD1 (IC50 = 5.27 μM for hLSD1). It effectively inhibits LSD1-mediated demethylation of H3K4Me2 and H3K4Me (IC50 ≤ 5 μM), without affecting H3K4Me3 and H3K9Me2 demethylation, nor the activities of LSD2 and JARID1A. Moreover, CBB1007 increases the levels of H3K4Me2 and H3K4Me (IC50 ≤ 5 μM) and activates epigenetically suppressed genes CHRM4/M4-ArchR and SCN3A in F9 cells (IC50 ≤ 3.74 μM). It preferentially inhibits the growth of pluripotent tumors with minimal impact on non-pluripotent cancer or normal somatic cells (IC50 ≥ 100 μM).