Science-Based Nutrition Dietary Supplement New Smaller Capsule, Easier to Swallow! 40,000 Serration Units Per Veggie Cap Suitable for Vegetarians Serrapeptase is a proteolytic enzyme isolated from the non-pathogenic bacteria Serratia species found in the digestive tract of the Japanese silkworm. The enzyme is used by the worms to digest their cocoons. Serrapeptase has been used as a nutritional supplement in Europe and Asia for nearly three decades. Each enteric-coated vegetarian capsule of Best Serrapeptase contains pure serrapeptase designed for optimal absorption in the intestinal tract.