Serrapeptidase is a highly efficient proteolytic (protein-digesting) enzyme originally discovered in a bacteria found in the gut of the Japanese silk worm. Years of investigative research suggest that this unique enzyme may have tremendous health-promoting potential with applications for joint health, circulatory support, respiratory function and immune defenses. Swanson Ultra® Optimum Potency Serrazimes features an innovative, vegetarian-friendly source of serrapeptidase cultured on Aspergillus through a natural process developed by the enzyme experts at National Enzyme Company. Serrapeptidase activity is measured in "serratiopeptidase units" and this formula delivers a powerful 40,000 units per capsule, compared to just 20,000 in our original high potency supplement.