Nattokinase: What It Is and How People Use It

Nattokinase is an enzyme made when soybeans are fermented into natto, a traditional Japanese food. People take nattokinase as a supplement because it helps break down fibrin, a protein involved in blood clotting. That’s why many look at it for circulation, blood pressure support, or reducing clot risk.

This page gives clear, practical info: what nattokinase may do, how people usually take it, safety concerns, and tips for picking a reliable product.

What the evidence says and common uses

Small human studies and lab research suggest nattokinase can reduce blood viscosity, improve circulation, and lead to modest drops in blood pressure in some people. It’s not a replacement for prescribed blood thinners, but some use it as a complementary approach for better blood flow.

People commonly try nattokinase for: mild circulatory support, helping maintain healthy blood pressure, and as a natural way to support normal clot breakdown. Expect results to be gradual — weeks rather than days.

How people take nattokinase and dosing tips

Supplements list activity in fibrinolytic units (FU) rather than milligrams. A typical dose range used in supplements is about 2,000–6,000 FU per day. Many labels recommend 2,000 FU once or twice daily. Follow the product label and talk to your doctor before starting, especially if you take other medicines.

Take nattokinase on an empty stomach if the label suggests it — some brands say this helps absorption and action on circulating proteins rather than digesting the enzyme. Keep a consistent routine so you can notice any changes or side effects.

Safety, interactions, and choosing a product

Be cautious if you take anticoagulant or antiplatelet drugs (warfarin, aspirin, clopidogrel, DOACs). Nattokinase can increase bleeding risk when combined with these. Stop nattokinase at least 1–2 weeks before planned surgery or dental work unless your clinician advises otherwise.

Avoid nattokinase if you are pregnant or breastfeeding unless a doctor approves. Side effects are usually mild but can include stomach upset or increased bleeding. Report any unusual bruising, nosebleeds, or heavy bleeding to your healthcare provider right away.

To pick a reliable supplement: choose brands that list FU activity, show third-party testing or certificate of analysis, and avoid blends that hide nattokinase under complex proprietary mixes. If you prefer food sources, eating natto provides natural nattokinase, though the taste and texture are strong and not for everyone.

Bottom line: nattokinase may offer gentle support for circulation and clot breakdown, but it’s not risk-free. Talk to your clinician about interactions with your meds, confirm a safe dose, and buy products with clear labeling and testing data.