Nattokinase is an enzyme extracted and purified from a Japanese food called natto, which is made from boiled soybeans that have been fermented with a type of bacteria called Bacillus subtilis var natto. Nattokinase is a serine protease of the subtilisin family, and it exhibits a strong fibrinolytic activity when in contact with human blood or blood clots. It works by inactivating plasminogen activator inhibitor 1 (PAI-1) . Nattokinase may thin the blood and help break up blood clots, which might protect against heart disease and conditions caused by blood clots such as stroke, heart attack, and others. People take nattokinase for cardiovascular diseases including heart disease, high blood pressure, high cholesterol, and stroke, but there is no good scientific evidence to support any of these uses. Nattokinase is sold as a dietary supplement and can be produced by recombinant means and in batch culture, rather than relying on extraction from natto.

Some of the potential benefits of nattokinase include reducing high blood pressure, breaking down fibrin in the blood that forms clots, and improving blood circulation. However, more research is needed to confirm these benefits. Nattokinase has been promoted as an alternative anticancer treatment based on the notion that it can help dissolve the fibrin coating around a tumor and increase oxygen supply in the blood to inhibit cancer cell growth. However, these mechanisms have not been proven in humans.

Nattokinase is commonly consumed in foods and has been eaten in Japan for hundreds of years. It is possibly safe when taken as medicine, and taking nattokinase supplements for up to 3 years seems to be safe. However, if you have any blood clotting disorders, dont take nattokinase supplements unless a doctor says its safe. You may need to stop taking nattokinase if youre planning to have surgery. Given the lack of evidence about its safety, doctors dont recommend nattokinase for children or for women who are pregnant or breastfeeding. If you take any medications regularly, talk to your doctor before you start using nattokinase supplements, as they could interact with blood thinners and other medications.