Leupeptin is widely used in biological research as a protease inhibitor, helping to prevent the degradation of proteins during cell lysis and protein extraction. It effectively inhibits several classes of proteases, including serine, cysteine, and threonine proteases, making it valuable in preserving sample integrity in biochemical assays.

It is commonly included in protein purification protocols and cell lysate preparation to maintain the stability of target proteins. Leupeptin also finds use in studies related to apoptosis, autophagy, and cellular signaling pathways where protease activity plays a regulatory role.

In addition, leupeptin has been explored for its potential neuroprotective properties in experimental models of brain injury and neurodegenerative diseases. It may help reduce ischemic damage in stroke models by inhibiting proteolytic enzymes activated during cellular stress.

Due to its ability to modulate protein breakdown, leupeptin is also applied in studies of lysosomal function and protein turnover in various cell types.