Nattokinase seems to alter blood coagulation chemistry, and there’s a concern it may increase the risk of bleeding. In people with mildly elevated cholesterol levels, taking 2,000 fibrinolytic units (FU) of nattokinase daily for 8 weeks prolonged the aPTT (activated partial thromboplastin time — a measure of how long it takes blood to clot).[1]
However, there have been only 2 reported cases of bleeding with nattokinase in older adults with cardiovascular conditions. In one case, 400 mg of nattokinase was taken daily for 7 days with aspirin (a blood thinner).[2] In the other case, an unknown, likely large dose of nattokinase (sometimes a “handful” of capsules) was taken daily.[3]
References
- ^Yoo HJ , Kim M , Kim M , Lee A , Jin C , Lee SP , Kim TS , Lee SH , Lee JHThe effects of nattokinase supplementation on collagen-epinephrine closure time, prothrombin time and activated partial thromboplastin time in nondiabetic and hypercholesterolemic subjects.Food Funct.(2019 May 22)
- ^Chang YY, Liu JS, Lai SL, Wu HS, Lan MYCerebellar hemorrhage provoked by combined use of nattokinase and aspirin in a patient with cerebral microbleeds.Intern Med.(2008)
- ^Ramachandran L, Aqeel A, Jafri A, Sidhu Y, Mohamed Djirdeh TNattokinase-Associated Hemoperitoneum in an Elderly Woman.Cureus.(2021 Dec)