DM MEDICINE CONTENT TEAM • Last updated: July 27, 2026
Nattokinase is an enzyme derived from natto, a fermented soy product in Japanese cuisine. In recent years, it is frequently encountered in circulation support, vascular health, and healthy aging products.
Although its name has only recently become well-known, natto is a food that has been consumed in Japan for centuries. Nattokinase, used as a supplement, is prepared to provide a specific enzymatic activity and offers a more concentrated form compared to the food.
What does nattokinase do in the body?
Our body forms clots when necessary and then breaks down this structure in a controlled manner. Nattokinase is researched through processes related to fibrin, which forms the network structure of clots. For this reason, products are mostly presented under the headings of “circulation” and “vascular support.”.
There is an important distinction here: supporting circulation does not mean treating a heart attack or stroke. Nattokinase is not a natural alternative to the blood thinner prescribed by a doctor.
Who chooses it, and why?
People who spend long hours at a desk, those with sedentary lifestyles, and those following a healthy aging program may be interested in this product. Some people choose it because of research on its effects on blood pressure and vascular elasticity.
However, the best circulatory support remains movement, weight control, a smoke-free life, and regular blood pressure monitoring. Nattokinase should be considered as a special support added alongside these foundational steps.
What does the FU value mean?
On nattokinase labels, we often see FU instead of milligrams. FU refers to fibrinolytic enzyme activity. Products providing 2,000 FU per serving are common on the market.
It is not correct to look only at the total weight of the capsule. Actual enzyme activity depends on the product’s manufacturing and storage quality. For this reason, the FU value and independent quality analysis are important.
How do I use it?
The products are generally recommended to be taken as one capsule per day, separate from meals. The reason for this is to ensure that the enzyme is used for targeted circulatory processes rather than for breaking down dietary proteins. However, you should always follow the instructions on the product label.
When using nattokinase for the first time, changes such as easy bruising, nosebleeds, or gum bleeding should be monitored. If a planned tooth extraction or surgery is scheduled, it must be reported to the healthcare team.
Who should not use it?
People taking medications that affect the risk of bleeding—such as warfarin, apixaban, rivaroxaban, dabigatran, clopidogrel, or aspirin—should not add nattokinase on their own. It may not be appropriate for those with bleeding disorders, a history of stroke, or active ulcers.
There is insufficient data regarding use during pregnancy and breastfeeding. Conditions such as sudden, severe headache, black stools, or unexpected bleeding should not be dismissed as side effects of the supplement but should be evaluated immediately.
Frequently Asked Questions
Is nattokinase a blood thinner?
It may affect circulation and fibrin processes; it is not a substitute for prescription blood thinners.
Is eating natto the same thing?
Natto is a food; the supplement is standardized to provide a specific level of enzymatic activity.
On an empty or full stomach?
Many products recommend taking them between meals; follow the instructions on the label.