NSK-SD Nattokinase 200 mg, Value Size, 60 Vegan Capsules, Source NaturalsSource Naturals NSK SD Nattokinase 200 mg Whole Body Systemic Enzyme for Healthy Circulation. Dietary Supplement. Nattokinase is a systemic enzyme isolated from the traditional Japanese soy food natto. It has been shown to support healthy blood flow by assisting the circulatory clearing system of the body. Supplement Facts Serving Size: 1 Capsule Amount Per Serving %DV Nattokinase 4,000 FU (NSK SD) 200 mg * *Daily Value not established. FU