What is the recommended dosage for Nattokinase?

General: 2,000 FU (fibrinolytic units)/day; Cardiovascular Support: 2,000-4,000 FU/day

What are the side effects of Nattokinase?

Potential side effects include: Generally well-tolerated, Increased bleeding risk (fibrinolytic activity), Mild gastrointestinal discomfort, Bruising (rare).

What is nattokinase and how may it support cardiovascular health?

Nattokinase is a fibrinolytic enzyme derived from natto, a traditional Japanese fermented soybean food. In vitro studies show it can break down fibrin, a blood clotting protein. Some clinical studies suggest it may reduce blood pressure, improve lipid profiles, and inhibit platelet aggregation. It is widely used in Japan and Korea.

What dosage of nattokinase has been studied in clinical trials?

Clinical studies have used 2,000–10,000 fibrinolytic units (FU) per day, typically equivalent to 100–200 mg. Blood pressure studies commonly used 2,000 FU daily for 8 weeks. The enzyme is measured in fibrinolytic units (FU) or fibrin degradation units (FDU). NSK-SD is a commonly studied form.

What are the potential side effects of nattokinase?

Nattokinase has significant anticoagulant effects and should not be combined with blood thinners (warfarin, heparin, aspirin, clopidogrel) due to serious bleeding risk. Discontinue at least 2 weeks before surgery. It should be avoided by individuals with bleeding disorders. Individuals with soybean allergies should use purified NSK-SD form.

Nattokinase

amino_acid

Also known as: Subtilisin NAT, NSK-SD, Natto Extract, Bacillus subtilis var. natto Protease

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About

Nattokinase is a serine protease from fermented soybeans that directly degrades fibrin and enhances endogenous fibrinolytic activity. A 2021 RCT (79 participants with subclinical atherosclerosis) showed nattokinase at 2,000 FU/day reduced carotid intima-media thickness progression over 12 months. It also demonstrated modest blood pressure reductions in meta-analyses.

How It Works

A serine protease that directly degrades fibrin through fibrinolytic activity and enhancement of endogenous t-PA while inhibiting PAI-1; reduces blood viscosity by decreasing fibrinogen and factor VIII levels; may reduce blood pressure through ACE-inhibitory activity; anti-atherosclerotic effects via LDL reduction.

Evidence For Conditions

Condition	Grade	Studies	Participants
Atherosclerosis	B	4	300	View →
High Blood Pressure (Hypertension)	C	6	400	View →

Side Effects

Generally well-tolerated
Increased bleeding risk (fibrinolytic activity)
Mild gastrointestinal discomfort
Bruising (rare)

Drug & Supplement Interactions

Anticoagulants — warfarin, DOACs (additive anticoagulant effects — contraindicated)
Antiplatelet drugs (additive bleeding risk)
NSAIDs (increased bleeding risk)
Fish oil at high doses (additive anticoagulant effect)

Always inform your healthcare provider about all supplements you take.

Related Ingredients

L-Arginine L-Citrulline Taurine

Quick Facts

Dosage: General: 2,000 FU (fibrinolytic units)/day; Cardiovascular_Support: 2,000-4,000 FU/day
Forms: capsule tablet
Natural Sources: Natto (Japanese fermented soybeans)
Upper Limit: Not formally established; up to 10,800 FU/day used in clinical trials
Best Time: On empty stomach (between meals) for optimal fibrinolytic activity

Evidence Summary

Atherosclerosis B

High Blood Pressure (Hypertension) C

FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products and information on this website are not intended to diagnose, treat, cure, or prevent any disease. The evidence grades presented are based on our analysis of published peer-reviewed research and do not constitute medical advice. Always consult your healthcare provider before starting any supplement regimen.