PI-1840 is primarily used as a selective inhibitor of protein tyrosine phosphatase 1B (PTP1B), an enzyme involved in the regulation of insulin and leptin signaling pathways. Due to this inhibitory action, it is widely utilized in research related to type 2 diabetes and obesity, helping scientists understand how enhancing insulin sensitivity can be achieved. It also shows potential in cancer research, particularly in studies involving HER2-positive breast cancer, where PTP1B inhibition may suppress tumor growth and signaling pathways. Its role in cellular assays and in vivo models makes it a valuable tool for exploring metabolic disorders and oncogenic mechanisms.