Nattokinase Dissolves Long-COVID Microclots: New Study

Part of the Blood Flow & Thrombosis Hub

This article belongs to our blood flow and thrombosis education series. For the full framework on circulation, clot formation, fibrinolysis, vascular support, and where nattokinase fits in the evidence, start with Blood Flow & Thrombosis Fundamentals.

Persistent “fibrinaloid” microclots are emerging as a driver of Long COVID and other thrombo-inflammatory disorders. A 2024 peer-reviewed study from the University of Liverpool and Stellenbosch University pairs automated microscopy with recombinant nattokinase to reveal how this soy-fermented enzyme dismantles those stubborn clots in real time.

Specific Aim — Can Nattokinase Break Down Amyloid-Like Fibrin Clots?

Researchers set out to quantify—in minutes rather than days—whether nattokinase can:

Lower the number and fluorescent intensity of Thioflavin-T-positive fibrinaloid microclots.
Shrink clot size under static and flow-like (shaking) conditions that mimic blood circulation.

Key Results — Faster Long-COVID Microclot Clearance

Endpoint	Control (no NK)	Vehicle (PBS)	Nattokinase 14 ng µL⁻¹ & 28 ng µL⁻¹	Outcome vs. Control (2 h)
Median clot count	Rising, then plateau	Similar to control	≈ 50 % drop at both doses	p = 0.0014 – 0.0003
Median clot intensity	High fluorescence	Slight fall	70 – 80 % lower	p = 0.015 – 0.0008
Median clot size	Gradual growth	Slight growth	Stabilised, no over-growth	Not significantly different (p > 0.12)

Flow (shaking) further decreased clot number but enlarged aggregate size, underscoring the importance of shear forces in vivo.

Takeaways — Why This Matters for Functional Health Brands

．Fast fibrinolysis: Half-life to noticeable clot reduction was ≈ 2 hours, confirming nattokinase’s rapid enzymatic action.

．Dose-responsive yet safe:Both 14 ng µL⁻¹ and 28 ng µL⁻¹ were effective without over-digestion, hinting at a practical safety window.

．Relevance to Long COVID: Microclot build-up correlates with fatigue and vascular symptoms; breaking them down could relieve downstream pathology.

．Automatable assay: The study’s imaging pipeline lets ingredient developers benchmark different nattokinase batches quickly, accelerating R&D.

💡Formulation tip: Clinical data suggest oral intakes of 2,000–8,000 FU day⁻¹ achieve systemic exposure; pairing with omega-3s may further dampen thrombo-inflammation.

FAQs

Q: Is nattokinase proven for Long COVID yet?
A: Not clinically—this is pre-clinical (in vitro, the same as another Nattokinase-Covid study) mechanistic evidence. Randomised trials are the logical next step.

Q: Will nattokinase thin my blood too much?
A: Unlike prescription thrombolytics, nattokinase shows a moderated activity curve; nevertheless, discontinue two weeks pre-surgery and consult your physician if you’re on anticoagulants.

References

Grixti et al., “Automated microscopic measurement of fibrinaloid microclots and their degradation by nattokinase, the main natto protease"”, 2024 (doi: https://doi.org/10.1101/2024.04.06.588397)