Z-LEHD-FMK is widely used in biochemical research as a specific inhibitor of caspase-9, a key enzyme involved in the intrinsic apoptosis pathway. It is particularly valuable in studies aimed at understanding the mechanisms of programmed cell death, as it helps to selectively block caspase-9 activity, allowing researchers to dissect its role in apoptosis. This compound is also employed in experiments to investigate the effects of inhibiting apoptosis in various cell types, including cancer cells, to explore potential therapeutic strategies. Additionally, Z-LEHD-FMK is utilized in models of neurodegenerative diseases and ischemic injuries to assess the protective effects of caspase-9 inhibition on cell survival. Its ability to penetrate cell membranes makes it a practical tool for in vitro and in vivo studies focused on apoptosis regulation.