What are nattokinase’s main benefits?

There is interest in using nattokinase for its cardiovascular benefits such as reducing blood clotting and lowering blood pressure.^[1][2][3] However, nattokinase does not seem to lower cholesterol nor reduce atherosclerosis. In a randomized trial in 265 adults with an average age of 65 years, taking 100 mg (2,000 fibrinolytic units (FU)) of nattokinase daily for about 3 years did not slow the progression of atherosclerosis compared to a placebo.^[4] The same dose taken for 6 months also did not lower cholesterol levels compared to a placebo,^[5] except when it was used in combination with red yeast rice, which is a natural source for the cholesterol-lowering drug lovastatin.^[6] Some researchers insist that higher doses of nattokinase may have a benefit for cholesterol. In fact, one large observational study in Chinese patients found that taking 10,800 FU of nattokinase daily for a year was associated with a reduction in cholesterol, while a lower dose of 3,600 FU daily was not associated with a reduction in cholesterol.^[7] This observational study cannot show cause and effect, so further interventional research is needed. It’s unclear if these effects are generalizable to other geographic locations.