LY 3000328 is a potent and selective cathepsin S inhibitor, with IC50 values of 7.7 nM (human) and 1.67 nM (mouse). It is a research tool for studying extracellular matrix remodeling, with applications in investigating abdominal aortic aneurysm (AAA) progression in preclinical models through the inhibition of elastin and collagen degradation.