LSD1-IN-31 (compound 11e) can directly bind to LSD1/CoREST complex to reduce LSD1 demethylation enzymatic activity. LSD1-IN-31 inhibits LSD1 demethylation activity and influences its downstream IκB/NF-κB signaling pathway. LSD1-IN-31 inhibits osteoclastic bone loss in vitro and in vivo. LSD1-IN-31 can be used for osteoporosis research.