NutriStack
Naproxen and Nattokinase, a caution.
Nattokinase may add fibrinolytic and anticoagulant effects to naproxen's GI bleeding risk. Naproxen is a higher-GI-risk NSAID, so a supplement that affects clot formation can make bleeding harder to control. The combination is higher risk around procedures, with ulcer history, or with other antithrombotic medicines.
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.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Naproxen 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 may add fibrinolytic and anticoagulant effects to naproxen's GI bleeding risk. Naproxen is a higher-GI-risk NSAID, so a supplement that affects clot formation can make bleeding harder to control. The combination is higher risk around procedures, with ulcer history, or with other antithrombotic medicines.
Mechanism. Nattokinase can enhance fibrinolysis and reduce clot stability, while naproxen inhibits COX-mediated prostaglandins and contributes to GI mucosal injury. Together they can increase both the chance of bleeding and the difficulty of stopping it.
Recommendation. Avoid nattokinase while taking naproxen regularly. Stop nattokinase before surgery or dental procedures unless your clinician directs otherwise, and report any unusual bleeding promptly.
Sources (2)
- Kurosawa Y, Nirengi S, Homma T, Esaki K, Ohta M, Clark JF, et al. A single-dose of oral nattokinase potentiates thrombolysis and anti-coagulation profiles. Sci Rep. 2015;5:11601. PMID 26109079
- Castellsague J, Riera-Guardia N, Calingaert B, Varas-Lorenzo C, Fourrier-Reglat A, Nicotra F, et al. Individual NSAIDs and upper gastrointestinal complications: a systematic review and meta-analysis of observational studies (the SOS project). Drug Saf. 2012;35(12):1127-1146. PMID 23137151
Stack Score
How this pair moves the number.
Effect on the composite score
If both Naproxen 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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