Used in research to inhibit intracellular cholesterol transport, U18666A is widely applied in studies of lipid metabolism and lysosomal storage disorders. It induces a cellular phenotype similar to Niemann-Pick type C disease, making it a valuable tool for modeling the disease in vitro. The compound also interferes with viral entry and replication, particularly for enveloped viruses, and has been used to study autophagy and endosome-lysosome function. Additionally, it serves in cancer research due to its ability to alter cholesterol homeostasis in tumor cells.