Lalistat 1 is a potent, selective, and competitive inhibitor of lysosomal acid lipase (LAL) and against purified human LAL (phLAL) with an IC50 of 68 nM. Lalistat 1 is a inhibitor of immunoglobulin A1 protease (IgA1P) proteases for H. influenzae, has less effects on other serine hydrolases (trypsin or β-lactamase, etc.). Lalistat 1 can be used for the research of niemann-pick type C (NPC) disease.