(Rac)-Calpain Inhibitor XII is primarily used in biochemical research to study the role of calpain enzymes in various cellular processes. It effectively inhibits calpain activity, making it a valuable tool for investigating its involvement in conditions such as neurodegeneration, muscle degeneration, and apoptosis. Researchers utilize this inhibitor to explore potential therapeutic strategies for diseases linked to excessive calpain activation, such as Alzheimer's, Parkinson's, and muscular dystrophy. Additionally, it aids in understanding calcium-dependent signaling pathways and their impact on cell function. Its application extends to in vitro experiments, where it helps delineate the mechanisms of calpain-mediated protein degradation and cellular damage.