NutriStack
Dabigatran and Nattokinase, a caution.
Nattokinase has fibrinolytic activity and can reduce clotting factors. Dabigatran directly inhibits thrombin, so combining the two may create additive anticoagulant and fibrinolytic effects. Major bleeding risk is especially concerning in older adults, kidney impairment, prior bleeding, or concurrent antiplatelet use.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
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At a glance
- Substances
- Dabigatran and Nattokinase
- Pair type
- Caution
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Emerging evidence
Caution
What is happening. Nattokinase has fibrinolytic activity and can reduce clotting factors. Dabigatran directly inhibits thrombin, so combining the two may create additive anticoagulant and fibrinolytic effects. Major bleeding risk is especially concerning in older adults, kidney impairment, prior bleeding, or concurrent antiplatelet use.
Mechanism. Nattokinase directly cleaves fibrin and has been shown to lower fibrinogen, factor VII, and factor VIII. These effects add to dabigatran's direct thrombin inhibition and can weaken hemostasis through separate pathways.
Recommendation. Avoid nattokinase while taking dabigatran. If you have already combined them, stop nattokinase and contact your prescriber promptly if you notice unusual bruising, black stools, blood in urine, severe headache, or weakness.
Sources (2)
- Chang YY, Liu JS, Lai SL, Wu HS, Lan MY. Cerebellar hemorrhage provoked by combined use of nattokinase and aspirin in a patient with cerebral microbleeds. Intern Med. 2008;47(5):467-469. PMID 18310985
- Hsia CH, et al. Nattokinase decreases plasma levels of fibrinogen, factor VII, and factor VIII in human subjects. Nutr Res. 2009;29(3):190-196. PMID 19358933
Stack Score
How this pair moves the number.
Effect on the composite score
If both Dabigatran and Nattokinase are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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