Image by Narupon Promvichai from Pixabay

Nattokinase is an enzyme that comes from a Japanese soy dish called natto, fermented with the bacteria Bacillus subtilis natto. Proteolytic enzymes chew up proteins, and nattokinase specifically has an affinity for blood clots and atherosclerosis or heart disease. Most anticoagulant medications can prevent clot formation, but aren’t as useful for a clot that already exists. Enzymes are more useful for that job.

Here’s the data behind nattokinase as a natural cardiovascular support. 

Effects of Nattokinase on Blood Clotting Markers

According to this study, nattokinase works at least in part by interrupting the process of oxidative stress and inflammation which leads to clotting. 

This study, though small and performed on healthy subjects, demonstrates that nattokinase is effective in lowering a number of clotting markers, including D-Dimer, fibrinogen, and Factor VIII.

This study demonstrates that nattokinase is as effective as a body weight dose of aspirin in clot prevention (and without the NSAID side effects). 

Effects of Nattokinase on Post-Stroke Damage

In this animal study, nattokinase deceased the severity of damage from a subsequent stroke. 

Even after a stroke, this study shows that nattokinase can improve subsequent blood flow—and healing is in the blood, of course. 

Effects of Nattokinase on Progression of Atherosclerosis 

Atherosclerosis, or heart disease, is (somewhat arguably) caused by clotting on the blood vessel lining. Because of this, if nattokinase is helpful for free-floating thrombi (clots), it stands to reason that it might also be useful clinically for heart disease in general as well. 

This study does show that daily nattokinase at 6000 fibrin units (FU) which translates to about 300 mg daily does indeed help to slow the progression of heart disease and mitigate the risks of stroke and heart attack. 

Effects of Nattokinase on Vascular Health

This study also shows that those with phlebitis (inflammation of a vein) or venous insufficiency can benefit from nattokinase. Both men and women across a broad range of ages experienced clinical benefit from both conditions (as well as Deep Vein Thrombosis, or DVT, which fits under the previous clotting discussion), without experiencing any adverse effects or progression of symptoms. 

Contraindications and Cautions

Of course anyone with the opposite risk of excessive bleeding risk, due to a condition like hemophilia or other prescribed blood thinners, should not take nattokinase. It’s also poorly studied in pregnancy and breast feeding, and so is contraindicated. 

In my experience, some who may suffer from chronic infections of various kinds might also want to be cautious—nattokinase can also function as a biofilm buster, which can lead to unexpected die-off if they jump to a high dose too quickly. For this reason, I often start low and taper up if I suspect this might be a concern.