What Does Nattokinase Do for Your Body?

One enzyme, pulled from a sticky Japanese breakfast food, can measurably change the way your blood flows within hours of swallowing it.

Nattokinase comes from natto, a fermented soybean food eaten in Japan for centuries, and its clot-dissolving activity was first identified by researchers in the 1980s. In healthy adults, even a single 2,000 FU dose has been shown to shift blood markers of clotting and clot breakdown. Here is what the evidence says it actually does for your body — and, just as important, what it does not.

Table of Contents

• 1. What Nattokinase Actually Is
• 2. How It Works in Your Body
• 3. What It Does for Blood Pressure
• 4. What It Does for Circulation and Blood Flow
• 5. Other Effects Researchers Are Studying
• 6. What Nattokinase Does Not Reliably Do
• 7. Getting a Consistent, Verified Dose
• Frequently Asked Questions
• Conclusion

1. What Nattokinase Actually Is

Nattokinase is an enzyme — a protein that speeds up one specific chemical reaction — produced when the bacterium Bacillus subtilis ferments soybeans into natto. Chemically, it is a subtilisin-like serine protease made of 275 amino acids, first characterized after Japanese scientists noticed natto could dissolve blood clots in a lab dish.

Its strength is not measured in milligrams but in "fibrinolytic units" (FU), a lab measure of how fast it breaks down fibrin. Most clinical research clusters around 2,000 FU per day, though studies have used anywhere from 1,200 to more than 10,000 FU. One distinction matters: nattokinase is the isolated enzyme, while natto the food also carries vitamin K2, fiber, and other compounds — so the food and the supplement do not behave identically. For a broader primer, see our complete guide to nattokinase.

2. How It Works in Your Body

When you get a cut, your body builds a clot by weaving a mesh of a protein called fibrin. To clean that mesh up afterward, you rely largely on a single enzyme — plasmin. Nattokinase is unusual because it can break down fibrin directly, acting as a stand-in for your own cleanup crew.

It also works indirectly by supporting that crew. Nattokinase prompts the cells lining your blood vessels to release more tissue plasminogen activator (tPA) — the signal that switches on plasmin — and it cleaves and inactivates PAI-1, the molecule that normally slows clot breakdown down.

These effects are not just theoretical. In healthy volunteers, a single 2,000 FU dose shifted blood markers of clot breakdown and coagulation within hours, and a separate human study found that daily use lowered three drivers of clotting — fibrinogen, factor VII, and factor VIII.

3. What It Does for Blood Pressure

The most consistent human evidence is for blood pressure. In a randomized, double-blind trial of 73 adults with pre- or stage-1 hypertension, 2,000 FU daily for 8 weeks lowered systolic pressure by about 5.5 mmHg and diastolic by about 2.8 mmHg versus placebo.

Pooling the trials tells a similar, if more modest, story: a 2023 meta-analysis of 6 randomized trials (546 participants) found average reductions of roughly 3.4 mmHg systolic and 2.3 mmHg diastolic. A separate North American trial in people eating a typical Western diet also saw blood pressure fall, alongside a roughly 15% drop in von Willebrand factor, a marker tied to clotting risk.

How does it happen? Beyond thinning the blood, nattokinase's breakdown fragments appear to inhibit angiotensin-converting enzyme (ACE) — the same target as a common class of blood-pressure drugs. The effect is real but modest, so nattokinase is best seen as a possible complement to, not a replacement for, proven steps like diet, exercise, and prescribed medication.

4. What It Does for Circulation and Blood Flow

Thick, sludgy blood moves poorly, and several of nattokinase's measured effects point toward thinner, more freely flowing blood. In laboratory testing, the enzyme reduced red-blood-cell aggregation and lowered whole-blood viscosity across a range of concentrations (about 15 to 125 units/mL), and did so in a dose-dependent way.

It also appears to make platelets less sticky. Reviews describe nattokinase inhibiting platelet aggregation and improving blood-flow measures, with some authors suggesting its overall profile may rival aspirin for supporting circulation — though that comes from early research, not head-to-head trials. Combined with its ability to lower clotting factors like fibrinogen, the picture is of an enzyme that gently discourages the conditions that let clots form. Because these same properties thin the blood, anyone on anticoagulant or antiplatelet medication, or with a bleeding disorder, should talk to a doctor before using it.

5. Other Effects Researchers Are Studying

Beyond clots and pressure, nattokinase is being explored for effects that are promising but far less settled. In cell and animal studies, it appears to blunt inflammation and oxidative stress — two processes that drive blood-vessel damage — by interrupting inflammatory signaling.

Laboratory work has also examined nattokinase in models of cerebral ischemia, where it showed protective, clot-clearing activity. Nearly all of this work is preclinical and a long way from proof in people, so it belongs firmly in the "worth watching," not "established," column.

6. What Nattokinase Does Not Reliably Do

Nattokinase is often marketed as a way to "clean out" arteries, and here the evidence gets weaker — so honest reporting matters. High-dose studies are encouraging: in a 26-week trial, 6,000 FU daily reduced carotid plaque size more than a statin did, and a large 2022 study using 10,800 FU daily for a year reported meaningful reductions in plaque and improved cholesterol.

But those doses are three to five times the typical 2,000 FU capsule — and at that everyday dose, the results do not hold up. The largest and longest trial to date followed 265 older adults on 2,000 FU for a median of 3 years and found no significant difference in artery-wall thickening versus placebo. Meta-analysis also found that low-dose nattokinase did not meaningfully improve cholesterol, and in some analyses slightly worsened it.

Two limits deserve emphasis. First, nattokinase is not a substitute for prescription blood thinners: case reports document serious bleeding, including a cerebellar hemorrhage in a patient combining nattokinase with aspirin. Second, most human trials are small and short, so the long-term picture is still thin. Nattokinase can support cardiovascular health — but it is not a treatment for heart disease, and it works best as one piece of a bigger plan. You can read more about its natural blood-thinning properties and drug interactions before starting.

7. Getting a Consistent, Verified Dose

If nattokinase's effects depend on getting an active, clinically relevant dose, then two things matter most: potency you can trust and delivery that gets the enzyme where it works. Enzymes are fragile, and stomach acid can degrade nattokinase before it is absorbed.

BioAbsorb Nattokinase Enzyme is built around those two problems. Each capsule delivers 100 mg standardized to 2,000 FU — the activity level most human studies have used — and every batch is third-party tested to confirm at least 2,000 FU, along with screening for heavy metals and microbial contaminants. Rather than a standard enteric coating, it uses a delayed-release DRcaps capsule that shields the enzyme from stomach acid without the phthalates and plasticizers found in some coated capsules, releasing it in the small intestine where absorption happens.

It is also deliberately free of vitamin K2 — a natto component that can interfere with warfarin — which allows longer-term dosing without stacking K2, and matters for readers already supplementing it. The formula is non-GMO, 100% vegetarian, and free of gluten, dairy, eggs, fish, shellfish, and nuts, made in a GMP-certified Canadian facility. Taken as a single daily capsule, a [PACK COUNT NEEDED]-count bottle works out to about [PRICE PER DAY NEEDED] per day.

Frequently Asked Questions

How long does nattokinase take to work?

Its blood-thinning activity begins fast — in healthy volunteers, a single 2,000 FU dose shifted clot-related markers within hours. Blood-pressure changes, by contrast, showed up over about 8 weeks of daily use in trials, so effects on different systems appear on very different timelines.

Is nattokinase a natural blood thinner?

It has blood-thinner-like effects — breaking down fibrin, lowering clotting factors, and reducing platelet stickiness — but it is not equivalent to prescription anticoagulants and cannot safely replace them. Anyone on warfarin, aspirin, or similar drugs should only use it under medical supervision.

What dose of nattokinase is used in studies?

Most human research uses 2,000 FU per day, within a broader range of 1,200 to over 10,000 FU across trials. Higher doses show stronger effects on plaque and cholesterol but have not been tested for long-term safety as thoroughly.

Can nattokinase lower blood pressure?

In trials it produced modest reductions — about 5.5 mmHg systolic in one 8-week study, and roughly 3.4 mmHg systolic when trials are pooled. It is a possible complement to, not a replacement for, standard blood-pressure care.

Does nattokinase clear plaque from arteries?

Only high doses of 6,000–10,800 FU have shown plaque reduction; at the typical 2,000 FU dose, the largest 3-year trial found no significant effect on artery-wall thickening. The plaque-clearing claim is not established at everyday supplement doses.

Who should avoid nattokinase?

People taking anticoagulant or antiplatelet medication, those with bleeding disorders, anyone scheduled for surgery, and people with a soy allergy should avoid it or consult a doctor first.

Conclusion

So what does nattokinase do for your body? The best evidence shows it breaks down fibrin, gently thins the blood, and modestly lowers blood pressure — with pooled trials showing reductions of about 3.4 mmHg systolic — while its bolder reputation for clearing arteries holds up only at high doses. Used realistically, and with a doctor's input if you take medication, it can be a sensible part of a heart-health routine. Explore a third-party-tested, 2,000 FU option in BioAbsorb's Nattokinase Enzyme.

Research References

1. Effects of nattokinase on blood pressure: a randomized, controlled trial. Hypertension Research, Vol. 31 (2008). Found that 2,000 FU/day for 8 weeks reduced systolic blood pressure by 5.55 mmHg and diastolic by 2.84 mmHg versus placebo.
2. Nattokinase Supplementation and Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Reviews in Cardiovascular Medicine, Vol. 24 (2023). Pooled RCTs showed significant reductions in systolic (−3.45 mmHg) and diastolic (−2.32 mmHg) blood pressure, but no lipid benefit at low doses.
3. Nattokinase atherothrombotic prevention study (NKAPS): A randomized controlled trial. Clinical Hemorheology and Microcirculation, Vol. 78 (2021). In 265 adults over a median 3 years, 2,000 FU/day did not significantly slow carotid artery-wall thickening versus placebo.
4. The profibrinolytic enzyme subtilisin NAT purified from Bacillus subtilis cleaves and inactivates plasminogen activator inhibitor type 1. The Journal of Biological Chemistry, Vol. 276 (2001). Identified PAI-1 inactivation as a key mechanism by which nattokinase enhances fibrinolysis.
5. Nattokinase-promoted tissue plasminogen activator release from human cells. Pathophysiology of Haemostasis and Thrombosis, Vol. 36 (2008). Showed nattokinase increases release of tPA, the activator of the body's own clot-dissolving system.
6. Purification and characterization of a strong fibrinolytic enzyme (nattokinase) in the vegetable cheese natto. Biochemical and Biophysical Research Communications, Vol. 197 (1993). Characterized nattokinase as a 275-amino-acid, subtilisin-like serine protease that digests fibrin directly.
7. A single-dose of oral nattokinase potentiates thrombolysis and anti-coagulation profiles. Scientific Reports, Vol. 5 (2015). A single 2,000 FU dose enhanced fibrinolytic and anticoagulant markers in healthy adults within hours.
8. Nattokinase decreases plasma levels of fibrinogen, factor VII, and factor VIII in human subjects. Nutrition Research, Vol. 29 (2009). Daily nattokinase reduced three clotting-related factors in human subjects.
9. Effects of nattokinase, a pro-fibrinolytic enzyme, on red blood cell aggregation and whole blood viscosity. Clinical Hemorheology and Microcirculation, Vol. 35 (2006). Demonstrated a dose-dependent decrease in red-blood-cell aggregation and whole-blood viscosity in vitro.
10. Consumption of nattokinase is associated with reduced blood pressure and von Willebrand factor: a North American clinical trial. Integrated Blood Pressure Control, Vol. 9 (2016). A vitamin K2-removed nattokinase reduced blood pressure and lowered von Willebrand factor by ~15% in a Western-diet population.
11. A clinical study on the effect of nattokinase on carotid artery atherosclerosis and hyperlipidaemia. Zhonghua Yi Xue Za Zhi (National Medical Journal of China), Vol. 97 (2017). At 6,000 FU/day for 26 weeks, nattokinase reduced carotid plaque size more than simvastatin (Chinese-language report, English abstract).
12. Effective management of atherosclerosis progress and hyperlipidemia with nattokinase: a clinical study with 1,062 participants. Frontiers in Cardiovascular Medicine, Vol. 9 (2022). High-dose nattokinase (10,800 FU/day for 12 months) reduced plaque and improved cholesterol.
13. Cerebellar hemorrhage provoked by combined use of nattokinase and aspirin in a patient with cerebral microbleeds. Internal Medicine, Vol. 47 (2008). Documented a serious bleeding event when nattokinase was combined with aspirin.
14. Nattokinase: A Promising Alternative in Prevention and Treatment of Cardiovascular Diseases. Biomarker Insights, Vol. 13 (2018). Reviewed nattokinase's antiplatelet and blood-flow effects across the research literature.
15. Mechanisms of Nattokinase in protection of cerebral ischemia. European Journal of Pharmacology, Vol. 745 (2014). Preclinical study showing protective, clot-clearing activity in cerebral-ischemia models.
16. Breaking the vicious loop between inflammation, oxidative stress and coagulation: a novel anti-thrombus insight of nattokinase. Redox Biology, Vol. 32 (2020). Found nattokinase inhibited inflammation and oxidative stress in experimental models.
17. Nattokinase — Integrative Medicine. Memorial Sloan Kettering Cancer Center (accessed 2026). Overview of nattokinase's antithrombotic activity, bleeding-risk considerations, and drug interactions.

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.