Science-Based Nutrition Helps Support Cardiovascular and Circulatory Health Dietary Supplement Nutrition / Non-gmo / Gluten Free Nattokinase is an enzyme derived from ""natto,"" a traditional fermented soy food popular in Japan. During the natto production process, non-gmo soybeans are boiled and fermented with friendly Bacillus subtilis bacteria producing nattokinase. Doctor's Best Nattokinase contains nattokinase enzyme with Vitamin K2 removed. Nattokinase has been shown to support a healthy circulatory system by helping to maintain normal fibrinogen levels in blood. Helps support a healthy circulatory system.