Nattokinase
Also known as: NK, nattō kinase, fermented soybean nattō enzyme
Randomized controlled trials in humans show that a single 2,000 FU oral dose of nattokinase produces transient increases in fibrinolysis markers (D-dimer, fibrin degradation products), prolongation of aPTT and small declines in factor VIII within hours, all remaining in normal ranges. Longer randomized trials yield mixed clinical results: a large 3-year trial (2,000 FU/day) found no effect on progression of carotid intima-media thickness, carotid stiffness, blood pressure or standard laboratory measures in low-CVD-risk adults; a 6-month 8,000 FU/day trial in patients with asymptomatic intracranial/carotid stenosis found no improvement in global cognition but a small domain-specific benefit in visuospatial function; a small trial in subacute ischemic stroke reported improvements on clinical scales when nattokinase was used as an adjuvant, and a 4-month trial of a combined nattokinase–Monascus product reported improvements in LDL and total cholesterol but the product contained other lipid-active ingredients so the specific contribution of nattokinase is unclear.
Last reviewed: 2026-10-14 · 5 indexed studies
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Overview
Nattokinase is an enzyme preparation derived from the traditional Japanese food nattō and consumed as an oral supplement for putative cardiovascular benefits. Human randomized trials report short-term changes in fibrinolysis/coagulation markers but mixed results for long-term clinical or structural cardiovascular outcomes.
Mechanism & Function
Mechanism of Action
Nattokinase appears to exert fibrinolytic and anticoagulant effects via enhancement of fibrin degradation (increased D-dimer and fibrin degradation products), increases in antithrombin, reductions in factor VIII activity and transient prolongation of activated partial thromboplastin time. These biochemical effects provide a plausible mechanism for effects on blood rheology and thrombolysis.
Physiological Role
Exogenous enzymatic fibrinolysis and modulation of coagulation factor activity when taken orally.
Primary Pathways
Performance / Health Relevance
Direct performance or ergogenic benefits have not been demonstrated. Biochemical effects on fibrinolysis could theoretically influence thrombotic risk or recovery from thrombotic events, but clinical outcome trials do not show consistent benefits.
Evidence Review
No meta-analyses or systematic reviews indexed for this ingredient yet.
Dimensions marked N/A have no indexed evidence of that class. They are shown as unavailable rather than scored.
Practical Use & Dosage
- Minimum Effective Dose
- 2,000 FU (single-dose studies demonstrated short-term fibrinolytic effects)
- Optimal Range
- 2,000–8,000 FU/day (range observed across RCTs; optimal clinical dose not established)
- Upper / Caution Level
- Not established
- Timing
- Not established from available trials
- Best Format
- Oral capsule/tablet containing nattokinase (fermented soybean-derived enzyme)
- Bioavailability
- Despite being a protein enzyme, oral administration produced measurable systemic changes in coagulation/fibrinolysis markers in human trials, suggesting some bioactivity after ingestion.
- Absorption Considerations
- Human trials report pharmacodynamic effects after oral dosing, but details on stability across gastric digestion and optimal formulations are not provided in the cited abstracts.
Safety & Interactions
Side Effects
- •Transient changes in coagulation/fibrinolysis markers (increased D-dimer, FDPs; prolonged aPTT)
- •Minor gastrointestinal symptoms reported in some trials (not consistently)
Contraindications
- Concomitant use with anticoagulant or antiplatelet therapy without physician supervision
- Known bleeding disorders
Drug Interactions
- •Anticoagulants (e.g. warfarin, DOACs) and antiplatelet agents — potential additive bleeding risk
Who Should Avoid
- •People on prescription anticoagulants or with bleeding diatheses
- •Those preparing for surgery without medical advice
- •Pregnant or breastfeeding women (insufficient data)
Monitoring
Consider monitoring coagulation parameters and clinical bleeding signs when used with anticoagulant medications; consult a clinician before use.
Frequently Asked Questions
Auto-generated from indexed evidence — dosage, safety, interactions, and more.
When is Nattokinase typically used or indicated?
Nattokinase is most commonly used for: Support for cardiovascular health markers, Support for healthy blood rheology / fibrinolysis, Adjunctive support during post-stroke rehabilitation, Support for blood lipids (when combined with other ingredients). Exogenous enzymatic fibrinolysis and modulation of coagulation factor activity when taken orally.
How does Nattokinase work?
Nattokinase appears to exert fibrinolytic and anticoagulant effects via enhancement of fibrin degradation (increased D-dimer and fibrin degradation products), increases in antithrombin, reductions in factor VIII activity and transient prolongation of activated partial thromboplastin time. These biochemical effects provide a plausible mechanism for effects on blood rheology and thrombolysis.
What is the recommended dose of Nattokinase?
The optimal range is 2,000–8,000 FU/day (range observed across RCTs; optimal clinical dose not established). with a minimum effective dose of 2,000 FU (single-dose studies demonstrated short-term fibrinolytic effects). Best taken: Not established from available trials. Upper / caution level: Not established.
What are the side effects of Nattokinase?
Reported side effects include: Transient changes in coagulation/fibrinolysis markers (increased D-dimer, FDPs; prolonged aPTT); and Minor gastrointestinal symptoms reported in some trials (not consistently). Monitoring: Consider monitoring coagulation parameters and clinical bleeding signs when used with anticoagulant medications; consult a clinician before use.
Does Nattokinase interact with medications?
Known or theoretical interactions: Anticoagulants (e.g. warfarin, DOACs) and antiplatelet agents — potential additive bleeding risk. Always check with a clinician before combining with prescription medication.
Who should avoid Nattokinase?
Nattokinase is generally not recommended for: People on prescription anticoagulants or with bleeding diatheses; Those preparing for surgery without medical advice; Pregnant or breastfeeding women (insufficient data); Concomitant use with anticoagulant or antiplatelet therapy without physician supervision; and Known bleeding disorders.
How strong is the evidence for Nattokinase?
Evidence level: Moderate (overall score 62/100), based on 5 indexed studies on SuppIndex.
Research & References (5)
Nattokinase atherothrombotic prevention study: A randomized controlled trial.
Double-blind RCT of 265 adults (median age 65.3) randomized to oral nattokinase 2,000 FU/day or placebo for a median of 3 years, assessing carotid intima-media thickness (CIMT), carotid arterial stiffness, blood pressure and laboratory markers.
The Effect of Nattokinase-Monascus Supplements on Dyslipidemia: A Four-Month Randomized, Double-Blind, Placebo-Controlled Clinical Trial.
120-day randomized, double-blind trial of a combination nattokinase–Monascus supplement versus placebo in 113 subjects with dyslipidemia, measuring lipids and CIMT.
Nattospes as Effective and Safe Functional Supplements in Management of Stroke.
Single-blinded RCT in 61 patients with subacute ischemic stroke testing Nattospes as an adjunct to standard care versus standard care alone over 60 days.
Nattokinase supplementation for cognitive enhancement in asymptomatic intracranial/carotid stenosis: A randomized controlled trial.
Single-centre double-blind RCT of 120 patients with asymptomatic intracranial/carotid stenosis randomized to nattokinase 8,000 FU/day or placebo for 6 months, assessing cognition and brain MRI.
A single-dose of oral nattokinase potentiates thrombolysis and anti-coagulation profiles.
Double-blind placebo-controlled crossover trial in 12 healthy young males receiving a single 2,000 FU oral dose of nattokinase with blood sampling up to 8 hours to assess coagulation and fibrinolysis markers.
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Research Overview
Moderate EvidenceCite this ingredient
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Stable URL
https://thesuppindex.com/ingredients/nattokinase
SuppIndex. (2026). Nattokinase: Evidence summary, dosage and clinical studies. Retrieved October 16, 2026, from https://thesuppindex.com/ingredients/nattokinase
Based on 5 indexed studies · Evidence level: Moderate.
Goal Ratings
Stack Compatibility
Avoid combining with anticoagulant/antiplatelet supplements or drugs without medical oversight. Evidence for additive lipid effects when combined with Monascus (red yeast rice) cannot isolate nattokinase's contribution.