K-604 dihydrochloride is primarily utilized in research settings as a selective inhibitor of acyl-CoA:cholesterol acyltransferase (ACAT). This enzyme plays a crucial role in cholesterol esterification, making the compound valuable for studying lipid metabolism and related diseases. Researchers employ it to investigate the mechanisms underlying atherosclerosis, as inhibiting ACAT can reduce the accumulation of cholesterol esters in arterial walls. Additionally, it is used in preclinical studies to explore potential therapeutic strategies for hypercholesterolemia and other lipid disorders. Its application extends to understanding the role of ACAT in foam cell formation, a key process in the development of cardiovascular diseases.