GUIDE — SUPPLEMENT

Nattokinase: Benefits, Side Effects, Dosing, and What the Evidence Shows

Dr. Regina Druz, MD, MBA, FACC, FMCP-M·Reviewed May 2026·2 min read
Quick summary

Nattokinase is a fibrinolytic enzyme from fermented soybeans. It dissolves fibrin, reduces blood viscosity, and modestly lowers blood pressure and LDL. Best for patients with hypercoagulability and vascular plaque concerns. Does not replace anticoagulants and must not be combined with warfarin or DOACs without physician supervision.

The evidence

Nattokinase is extracted from natto, a traditional Japanese fermented soybean food. Its primary cardiovascular action is fibrinolysis — it cleaves fibrin directly and activates endogenous plasminogen, the body’s natural clot-dissolving system.

A 2015 randomised controlled trial in Scientific Reports demonstrated nattokinase reduced coronary artery calcium (CAC) progression significantly versus placebo over 26 weeks. A 2022 meta-analysis of 12 RCTs confirmed reductions in LDL cholesterol, triglycerides, and fibrinogen. Blood pressure reductions averaged 5.6/2.8 mmHg systolic/diastolic.

Dose, form & what to look for

Dose

2,000–4,000 fibrinolytic units (FU) per day. Must be enteric-coated to survive stomach acid. Take on an empty stomach 30–60 minutes before meals. Dosing must be expressed in FU — not milligrams. Third-party tested, no proprietary blends.

Side effects & drug interactions

Critical

Nattokinase has fibrinolytic and mild antiplatelet activity. Patients on warfarin, apixaban, rivaroxaban, dabigatran, aspirin, or clopidogrel must not add nattokinase without physician supervision. Discontinue at least 2 weeks before any surgery. Avoid during pregnancy. Soy-allergic patients should consult their allergist before use.

Frequently asked questions

How long does nattokinase take to work?+

Fibrinolytic activity begins within hours, but meaningful cardiovascular effects — changes in fibrinogen, blood viscosity, or CAC score — require consistent daily use for 3–6 months minimum. Dr. Druz typically reassesses after 3 months with repeat bloodwork including fibrinogen, D-dimer, and a lipid panel.

Is nattokinase the same as eating natto?+

While natto contains nattokinase, the enzyme concentration varies and digestion reduces absorption. Supplemental enteric-coated capsules deliver a standardized, measurable fibrinolytic dose. Natto is a nutritious food, but for therapeutic intent a standardized supplement is more reliable.

Can nattokinase dissolve existing arterial plaque?+

No — a common misconception. Its mechanism is fibrinolytic, not calcium-dissolving. The CAC trial showing slowed progression suggests it may reduce the inflammatory and thrombotic components of plaque development, but it does not reverse established calcification.

Does nattokinase need to be taken indefinitely?+

There is no evidence stopping nattokinase causes rebound effects. Whether long-term use is warranted depends on your underlying risk markers. Dr. Druz re-evaluates supplementation annually based on repeat biomarkers including fibrinogen and CAC score.

Can I take nattokinase with blood pressure medication?+

Nattokinase has mild antihypertensive effects. If you are already on antihypertensive medication, this may cause additive lowering. Always inform your prescribing physician before starting nattokinase alongside antihypertensives.

References

  1. Fujita M, et al. Nattokinase decreases plasma levels of fibrinogen, factor VII, and factor VIII. Nutrition Research. 2011;31(10):785–791.
  2. Kim JY, et al. Nattokinase supplementation reduces total and LDL cholesterol. J Med Food. 2008;11(1):132–137.
  3. Ren NN, et al. Clinical study on nattokinase on carotid atherosclerosis. Zhonghua Yi Xue Za Zhi. 2017;97(26):2038–2042.
Medical disclaimer

This guide is for educational purposes only and does not constitute medical advice. Always consult a qualified physician before starting any supplement, particularly if you are taking anticoagulants, statins, or other cardiovascular medications.

Medically reviewed by Dr. Regina Druz, MD, MBA, FACC, FMCP-M — Board-Certified Integrative Cardiologist at Holistic Heart Centers, Roslyn, NY. Last reviewed: May 2026.

From the shop

Want personalized guidance?

Dr. Druz reviews supplementation in the context of your full cardiovascular profile and medications.