Fibrinolytic enzymes have attracted interest from researchers and supplement users alike because of their proposed ability to break down fibrin, the protein mesh at the center of blood clots. Two of the most studied examples are nattokinase, derived from fermented soybeans, and lumbrokinase, a complex of enzymes extracted from earthworms. Both are sold as dietary supplements, and both are the subject of a growing but still limited body of human research.
If you are weighing one against the other, it is worth understanding what each enzyme actually does, where the evidence is strongest, and where important gaps remain. Neither enzyme has been approved by the FDA to treat, cure, or prevent any disease, and this article is informational only, not a substitute for medical advice.
Key Takeaways
- Nattokinase is a single serine protease from fermented soybeans; lumbrokinase is a complex of multiple serine proteases from earthworms — both degrade fibrin but through slightly different profiles.
- Nattokinase has a somewhat larger and more geographically diverse human trial record; lumbrokinase evidence is sparser and less independently replicated.
- Neither enzyme is FDA-approved to treat, cure, or prevent any disease, and most supportive trials are small and short-term.
- Both carry meaningful bleeding risk and must not be combined with warfarin, aspirin, clopidogrel, heparin, or other anticoagulants or antiplatelets without physician supervision.
- Product standardization matters more for lumbrokinase than nattokinase given the enzyme complexity and variability between manufacturers.
What Is Nattokinase and How Does It Work?
Nattokinase is a serine protease enzyme produced by Bacillus subtilis during the fermentation of soybeans into the Japanese food natto. It was first isolated in 1987 by researcher Hiroyuki Sumi, who noticed that natto dissolved a fibrin clot in a laboratory experiment far more rapidly than other foods tested.
The enzyme works through two complementary pathways. First, it directly cleaves fibrin, the insoluble protein that forms the structural backbone of a clot. Second, it appears to upregulate the body’s own clot-dissolving system by increasing levels of tissue plasminogen activator (tPA) and inhibiting plasminogen activator inhibitor-1 (PAI-1). This dual action has made nattokinase one of the more intensively studied oral fibrinolytic supplements.
Human plasma studies have confirmed measurable fibrinolytic activity following oral supplementation, and small randomized controlled trials have also reported modest reductions in blood pressure. However, most of this research involves short durations and small participant numbers, so conclusions should be held carefully.
What Is Lumbrokinase and How Does It Work?
Lumbrokinase is not a single enzyme but a complex of at least six serine proteases extracted primarily from the earthworm species Lumbricus rubellus and related varieties. Earthworms have long been used in traditional Chinese medicine for cardiovascular and circulatory conditions, and the fibrinolytic activity of these extracts has been the subject of research since the 1990s.
Like nattokinase, lumbrokinase degrades fibrin directly. Some research also suggests it may inhibit platelet aggregation and modulate inflammatory pathways, though the mechanisms are less well characterized than those of nattokinase. Because lumbrokinase is a mixture of related enzymes rather than a single purified compound, standardization across products can be inconsistent, which complicates comparisons between studies.
Human trial data on lumbrokinase are sparse. Most published studies come from China and involve small sample sizes or non-randomized designs, making it difficult to draw firm conclusions about efficacy or the size of any clinical effect.
How Do the Two Enzymes Compare in Evidence Quality?
Nattokinase currently has a modest but somewhat more developed human trial record than lumbrokinase. Several small randomized trials have examined its effects on blood pressure, cardiovascular biomarkers, and clotting parameters, and at least some of this work has been conducted in Western research settings with independently audited methods.
Lumbrokinase research, by contrast, is more heavily concentrated in Chinese literature and has seen less independent replication. This does not mean the enzyme is ineffective, but it does mean that clinicians and informed consumers are working with a thinner and less diversified evidence base. Neither enzyme has been studied in large, long-duration, placebo-controlled trials powered to measure hard cardiovascular outcomes such as heart attack or stroke prevention.
In summary: nattokinase has a somewhat larger body of human data; lumbrokinase has a longer history of use in traditional practice but less robust trial evidence by contemporary standards. Both need more research before definitive claims can be made.
Dosing and Formulation Considerations
Nattokinase supplements are typically standardized in fibrinolytic units (FU), with many commercial products providing 2,000 FU per capsule. The amount used in published human studies has generally fallen in a range consistent with common commercial formulations, though optimal dosing has not been established by rigorous dose-finding trials.
Lumbrokinase products are often standardized in units called SU (serrapeptase units) or simply listed by milligram weight of earthworm extract, and standardization practices vary widely between manufacturers. This variability makes it harder to compare one product to another or to translate trial findings into practical dosing guidance.
Both enzymes are protein-based and in principle could be degraded by stomach acid and digestive proteases before absorption. Enteric coating is sometimes used to protect the enzyme through the stomach, and some researchers believe enteric-coated formulations may improve bioavailability, though this has not been rigorously confirmed in head-to-head trials.
Safety, Interactions, and Who Should Avoid These Supplements
The most important safety concern for both nattokinase and lumbrokinase is the risk of excessive bleeding, particularly when combined with anticoagulant or antiplatelet medications. Nattokinase must not be used alongside warfarin, heparin, aspirin, clopidogrel, or other agents that reduce clotting without explicit physician supervision. The same principle applies to lumbrokinase given its similar mechanism of action.
Anyone scheduled for surgery should discontinue nattokinase at least one week before the procedure. A comparable precautionary washout period is prudent for lumbrokinase, though specific guidance is less well established in published literature. Individuals with bleeding disorders, a history of hemorrhagic stroke, or active peptic ulcers should avoid both supplements unless a physician has evaluated the risk-benefit balance.
People taking natto as a food rather than a supplement should also be aware that natto contains substantial amounts of vitamin K2, which can counteract warfarin therapy independently of nattokinase activity. Nattokinase supplements are sometimes derived from natto but the vitamin K content varies by product.
Which Enzyme Might Be Right for Whom?
Neither enzyme is approved to treat any medical condition, and the decision to use either should be made in conversation with a qualified healthcare provider, especially for anyone with cardiovascular disease, clotting disorders, or who is taking any prescription medication. That said, nattokinase is generally the better-studied option for consumers seeking the most evidence-supported choice among the two.
Lumbrokinase may appeal to those who are interested in traditional Chinese medicine applications or who have read specific clinical literature suggesting benefits in particular contexts such as chronic inflammation. However, the product quality and standardization concerns noted above make due diligence on brand selection especially important.
Combining the two enzymes is sometimes discussed in integrative medicine contexts, but there is no peer-reviewed human trial evidence to support combined use, and the theoretical risk of additive anticoagulant effects would make physician oversight even more important in that scenario.
🛒 Where to Buy Nattokinase
- Doctor’s Best Nattokinase 2,000 FULab-tested / studied
capsules, 100 mg NSK-SD per vcap (2,000 FU) — Most widely referenced brand in clinical and integrative medicine contexts; uses Japan Bio Science Laboratory NSK-SD ingredient; vegetarian capsules; 90 count - NOW Foods Nattokinase 100 mg
capsules, 100 mg per vcap (2,000 FU) — Mainstream GMP-certified brand; affordable entry-level option; 90 vcaps; widely available - Source Naturals Nattokinase 100 mg
capsules, 100 mg per tablet (2,000 FU) — Long-established supplement brand; competitive pricing at 60 tablets; good for budget-conscious buyers familiar with the brand - Healthy Origins Nattokinase 2,000 FU
capsules, 100 mg per vcap (2,000 FU) — Best cost-per-serving option on Amazon; 180 vcap bottle; uses NSK-SD ingredient; popular bulk buy for long-term users
As an Amazon Associate we earn from qualifying purchases. Shilajit quality varies widely — always choose a product with a published third-party heavy-metal test (COA) before buying.
A Note on the Evidence
The human trial evidence for both nattokinase and lumbrokinase is limited in scale, duration, and geographic diversity, and the FDA has not evaluated either enzyme for treating, curing, or preventing any disease. Both have meaningful potential to increase bleeding risk and must not be used alongside anticoagulant or antiplatelet medications without physician supervision; consult a qualified healthcare provider before starting either supplement, particularly if you have any cardiovascular condition, take prescription medications, or are approaching a surgical procedure.
Frequently Asked Questions
Can nattokinase and lumbrokinase be taken together?
There is no human trial evidence evaluating combined use of these two enzymes, and taking both simultaneously would theoretically amplify fibrinolytic and antiplatelet activity, increasing bleeding risk. Anyone considering combination use should consult a physician before doing so.
Is nattokinase the same as eating natto?
No. Whole natto contains nattokinase but also significant amounts of vitamin K2, which has its own effects on coagulation and can interact with warfarin independently. Nattokinase supplements are typically extracted and in some cases vitamin K is removed, but product composition varies, so reading the label carefully matters.
How long does it take for nattokinase to work?
Human plasma studies have detected fibrinolytic activity within a few hours of oral supplementation, but the clinical time course for any cardiovascular benefit — if one exists — is not well established. Most trials that have measured blood pressure or clotting parameters have run for weeks to months.
Is lumbrokinase safe for long-term use?
Long-term safety data for lumbrokinase are limited. Most published trials are short in duration, and comprehensive safety profiling across diverse populations has not been done. Anyone using lumbrokinase regularly should do so under medical supervision, especially if they have any cardiovascular or bleeding history.
Do these enzymes survive digestion?
Proteins are typically broken down in the stomach and small intestine, which raises questions about oral bioavailability of enzyme supplements. Enteric-coated formulations are designed to bypass acid degradation, and some research has measured fibrinolytic markers in blood after oral dosing, suggesting at least partial absorption or indirect systemic effects, though the mechanism is not fully resolved.
Who should absolutely avoid both enzymes?
Anyone on anticoagulant or antiplatelet therapy, anyone with a bleeding disorder or history of hemorrhagic stroke, and anyone scheduled for surgery within one week should avoid both nattokinase and lumbrokinase unless cleared by a physician. Pregnant or breastfeeding individuals should also avoid these supplements due to insufficient safety data.
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.
