How Nattokinase Works?

In 1987, Japanese researchers reported that an enzyme extracted from fermented soybeans could break down fibrin, the protein scaffold that holds a blood clot together.

They named it nattokinase — a serine protease that later laboratory work clocked at roughly six times more efficient at cutting cross-linked fibrin than plasmin, your body's own clot-dissolving enzyme. Understanding how nattokinase works means holding two ideas at once: it attacks clots directly, and it prompts your body to clear more of them itself. This guide covers both mechanisms — and flags where the human evidence is strong versus still preliminary.

Table of Contents

1. What Nattokinase Is — and Where It Comes From
2. Mechanism One: Dissolving Fibrin Directly
3. Mechanism Two: Activating Your Body's Own System
4. What the Human Studies Actually Show
5. The Catch: Getting Past Your Stomach
6. BioAbsorb Nattokinase: Built Around the Enzyme's Biology
7. Frequently Asked Questions
8. Conclusion
9. Research References

1. What Nattokinase Is — and Where It Comes From

Nattokinase is a single-chain enzyme of 275 amino acids weighing about 28 kDa, and it belongs to the subtilisin family of serine proteases — sharing roughly 99.5% of its structure with subtilisin E. Crucially, it is the bacterium Bacillus subtilis var. natto, not the soybean, that produces the enzyme during fermentation.

The 1987 discovery measured an average fibrinolytic activity of about 40 CU per gram of natto, which is why supplement potency is reported in fibrinolytic units (FU) rather than milligrams of protein. That distinction matters: two products with the same milligram dose can carry very different enzyme activity, and the research that everyone cites is built on FU, not weight.

If you want the full picture before diving into the biology, our complete guide to what nattokinase is covers its origins, benefits, and safety in one place. This article zooms in on the single question underneath all of those: by what mechanism does this enzyme do anything at all?

2. Mechanism One: Dissolving Fibrin Directly

The headline mechanism is direct fibrinolysis. Nattokinase physically cleaves cross-linked fibrin into soluble fragments — the way scissors cut a net — without needing any help from the rest of your clotting system. That sets it apart from the clot-busting drug tPA, which works indirectly by converting plasminogen into plasmin first.

How hard does it cut? In controlled lab assays, nattokinase broke down cross-linked fibrin about 6 times more efficiently than plasmin by catalytic measure, and at an equivalent molar dose it dissolved a clot roughly 4 times faster than plasmin in rats. Those are striking numbers — but they come from test tubes and animal models, not from people taking capsules.

That gap is the single most important thing to keep in mind throughout this article: a potent, well-documented mechanism in vitro does not automatically translate into the same magnitude of effect at an oral supplement dose in a human body. The mechanism is real. The size of the real-world payoff is a separate question, answered in Section 4.

3. Mechanism Two: Activating Your Body's Own System

The second mechanism is arguably more interesting, because it works through your own biology. Reviews of the enzyme describe at least three indirect actions: nattokinase increases tissue plasminogen activator (tPA), degrades plasminogen activator inhibitor-1 (PAI-1), and converts pro-urokinase into urokinase. In plain terms, it releases more of your clot-dissolving machinery, removes the brake on it, and switches on a backup activator.

You can see these pathways operating in a single dose. In a double-blind, placebo-controlled crossover study of 12 healthy men, one 2,000 FU dose produced measurable shifts across several markers at once:

• D-dimer rose significantly at 6 and 8 hours after the dose
• Fibrin/fibrinogen degradation products (FDP) rose at 4 hours
• Factor VIII activity fell at 4 and 6 hours, and activated partial thromboplastin time lengthened at 2 and 4 hours

The honest caveat the authors themselves stress: all of these changes stayed within the normal physiological range. The enzyme nudged the system toward more fibrinolysis and slightly less coagulation — it did not push anyone into a thinned-blood state from a single dose.

4. What the Human Studies Actually Show

Mechanism is one thing; outcomes are another. The strongest human signal so far is on blood pressure. In an 8-week randomized, double-blind trial, 73 adults with pre- or stage-1 hypertension taking 2,000 FU daily saw net reductions of 5.55 mmHg systolic and 2.84 mmHg diastolic versus placebo, alongside a drop in renin activity of 1.17 ng/mL/h. A 2023 meta-analysis pooling 6 trials and 546 participants landed in the same direction, with systolic pressure down about 3.45 mmHg and diastolic down 2.32 mmHg, and no notable adverse events reported.

On clotting factors, an open-label study of 45 subjects taking 2 × 2,000 FU daily for two months recorded reductions in fibrinogen, factor VII, and factor VIII of roughly 9%, 14%, and 17% in healthy participants, with blood lipids unchanged. That study had no placebo arm, so its results are suggestive rather than definitive — a limitation worth naming directly. You can go deeper into what the blood pressure research shows once that article is live.

Here is the calibration that separates honest coverage from hype: nearly all of this evidence sits at the level of surrogate markers — blood pressure, clotting factors, fibrinolytic activity — across studies typically numbering a few dozen to a few hundred people. No trial has shown that nattokinase alone prevents heart attacks, strokes, or clot events. The 2023 meta-analysis explicitly concluded that more work is needed to establish whether benefits are dose-dependent. For the wider cardiovascular picture, see broader cardiovascular benefits.

5. The Catch: Getting Past Your Stomach

A fair objection to any oral enzyme is simple: it is a protein, so won't your stomach digest it before it does anything? Nattokinase is an alkaline enzyme, and its absorption is one of the open questions researchers themselves flag — exactly the kind of detail that separates careful sources from marketing copy.

The evidence that enough survives to matter is real, though. As far back as 1990, oral administration of nattokinase was shown to enhance fibrinolytic activity in plasma — a systemic effect that could only happen if active enzyme reached the bloodstream. The single-dose study above adds to this: marker changes appeared within 2 to 8 hours of one 2,000 FU oral dose, which is fast enough to confirm meaningful absorption.

This is precisely why delivery format is part of the mechanism conversation rather than a footnote. Protecting an acid-sensitive enzyme on its way through the stomach so it reaches the small intestine intact is a real design problem — which is the thinking behind BioAbsorb's delayed-release DRcaps capsule. For how absorption interacts with timing and amount, the right dose and timing is covered in its own guide.

6. BioAbsorb Nattokinase: Built Around the Enzyme's Biology

Most of what determines whether nattokinase can act the way the research describes is decided before you swallow the capsule — in the dose, the activity, and the delivery. BioAbsorb's Nattokinase Enzyme delivers 100 mg standardized to 2,000 FU per capsule — the same activity level used in the single-dose human study and the blood-pressure trials referenced above, so the product is anchored to what was actually studied rather than an arbitrary milligram figure.

The format is built for an acid-sensitive enzyme. The DRcaps delayed-release veggie capsule is designed to shield the enzyme from stomach acid and release it in the small intestine, without the phthalates and plasticizers found in some enteric coatings. It is also deliberately free of vitamin K2, which lets people dose at higher or longer-term levels without K2 accumulation concerns — relevant if you already supplement K2 separately.

On the trust signals a careful reader looks for: it is non-GMO, 100% vegetarian, and free of gluten, nuts, eggs, dairy, fish, and shellfish, manufactured in a Canadian GMP-certified facility with every batch third-party tested for activity, heavy metals, and microbial contaminants. A 180-capsule bottle runs $49.87 — roughly $0.28 per day. None of this changes the honest bottom line: a well-made supplement supports the mechanism, but the human outcome data is still limited, and anyone on blood thinners or with a clotting condition should involve a physician before starting.

7. Frequently Asked Questions

Does nattokinase actually dissolve existing blood clots in people?

In lab and animal models it dissolves clots directly, and in humans a single 2,000 FU oral dose measurably shifts clot-breakdown markers like D-dimer within hours. However, no human trial has shown that nattokinase alone dissolves clots or prevents clot-related events, so it should not be relied on to treat any clotting condition without medical supervision.

How is nattokinase different from blood thinners like warfarin?

Anticoagulants such as warfarin and antiplatelet drugs like aspirin mainly prevent clots from forming. Nattokinase is fibrinolytic — it helps break fibrin down and supports your body's own lysis pathways by raising tPA and degrading PAI-1. It is not a substitute for a prescribed blood thinner, and combining the two can increase bleeding risk, so this requires physician oversight.

How long does it take to work?

Effects show up on two timescales. Clot-breakdown markers shift within 2 to 8 hours of a single 2,000 FU dose, while blood-pressure changes in trials accumulated gradually over an 8-week period rather than overnight.

Does stomach acid destroy it before it can work?

Nattokinase is acid-sensitive, but oral studies dating back to 1990 show it still raises plasma fibrinolytic activity, meaning enough active enzyme reaches the bloodstream to matter. This is the reason acid-protective delivery formats are used rather than plain capsules.

Is nattokinase safe?

Across the trials pooled in a 2023 meta-analysis of 546 people, no notable adverse events were reported. The main caution is bleeding risk: people on anticoagulants, with bleeding disorders, or scheduled for surgery should speak with a doctor first, and most clinicians advise stopping it before procedures.

8. Conclusion

Nattokinase works on two fronts at once — it cleaves fibrin directly and amplifies your body's own clot-clearing pathways, with measurable effects on markers like D-dimer within hours of a 2,000 FU dose. The mechanism is well-characterized; the human outcome evidence is promising but still limited, which is exactly why dose, enzyme activity, delivery, and medical context all matter. If you have decided nattokinase fits your plan, BioAbsorb's 2,000 FU Nattokinase Enzyme is formulated around how the enzyme actually behaves in the body.

9. Research References

1. A novel fibrinolytic enzyme (nattokinase) in the vegetable cheese Natto; a typical and popular soybean food in the Japanese diet. Experientia, Vol. 43, No. 10 (1987). First identified nattokinase in natto and measured its fibrinolytic activity at about 40 CU per gram of the food.
2. Enhancement of the fibrinolytic activity in plasma by oral administration of nattokinase. Acta Haematologica, Vol. 84, No. 3 (1990). Demonstrated that oral nattokinase raises fibrinolytic activity in plasma, indicating active enzyme reaches systemic circulation.
3. A single-dose of oral nattokinase potentiates thrombolysis and anti-coagulation profiles. Scientific Reports, Vol. 5 (2015). A 2,000 FU single dose in 12 healthy men significantly raised D-dimer and fibrin degradation products and lowered factor VIII, with all values remaining within the normal range.
4. Effects of Nattokinase on Blood Pressure: A Randomized, Controlled Trial. Hypertension Research, Vol. 31, No. 8 (2008). In 73 adults with pre- or stage-1 hypertension, 2,000 FU daily for 8 weeks reduced systolic and diastolic blood pressure by 5.55 and 2.84 mmHg versus control.
5. Nattokinase decreases plasma levels of fibrinogen, factor VII, and factor VIII in human subjects. Nutrition Research, Vol. 29, No. 3 (2009). An open-label study of 45 subjects found reductions of roughly 9%, 14%, and 17% in fibrinogen, factor VII, and factor VIII after two months, with lipids unchanged.
6. Nattokinase: An Oral Antithrombotic Agent for the Prevention of Cardiovascular Disease. International Journal of Molecular Sciences, Vol. 18, No. 3 (2017). Review describing nattokinase's direct fibrin hydrolysis plus its conversion of pro-urokinase to urokinase, degradation of PAI-1, and increase in tPA.
7. Nattokinase: A Promising Alternative in Prevention and Treatment of Cardiovascular Diseases. Biomarker Insights, Vol. 13 (2018). Comprehensive review of nattokinase's fibrinolytic, antihypertensive, and antiplatelet actions, and of the outstanding questions around its pharmacokinetics.
8. Nattokinase Supplementation and Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Reviews in Cardiovascular Medicine, Vol. 24, No. 8 (2023). Pooling 6 trials and 546 participants, found significant reductions in systolic (3.45 mmHg) and diastolic (2.32 mmHg) blood pressure and called for more research on dose-dependence.
9. Characterization of nattokinase-degraded products from human fibrinogen or cross-linked fibrin. Fibrinolysis, Vol. 9 (1995). In vitro clot lysis assays showed the cleavage of cross-linked fibrin by nattokinase was 6 times more efficient than by plasmin (kcat/Km); at an equivalent molar dose, nattokinase dissolved a thrombus approximately 4 times faster than plasmin in a rat model.

About the Author

David Kimbell is a health writer, digital entrepreneur and former aerospace engineer, based in Ottawa, Canada. He loves translating complex science into clear, actionable guidance for consumers seeking evidence-based solutions.

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Important Disclaimers

Medical Disclaimer: This article provides educational information only and is not intended as medical advice. Always consult with a qualified healthcare provider before starting any new supplement, especially if you have existing health conditions, take medications, or are pregnant or nursing.

FDA/Health Canada Statement: These statements have not been evaluated by the Food and Drug Administration or Health Canada. This product is not intended to diagnose, treat, cure, or prevent any disease.