Other ·Moderate evidence ·Reviewed May 2026
Enzyme from fermented soybeans (natto) with blood clot-dissolving properties.
The bottom line
Evidence rating moderate. Most-documented uses: cardiovascular health, blood flow, clot prevention. 17 sources indexed (2008–2026), with 22 interaction records on file.
Core mechanism
Serine protease that directly cleaves fibrin in blood clots. Also converts plasminogen to plasmin (endogenous fibrinolysis), degrades PAI-1, and mildly inhibits ACE for blood pressure support.7,8
Take on empty stomach for systemic absorption; with food for GI benefit1,2
Dosing protocol
Counsel on bleeding risk with anticoagulants and antiplatelets. Take away from meals.4
Ranked by evidence and value.
Real-world pricing across three quality tiers. Assumes Nattokinase 2,000-4,000 FU.
Assumes 2,000-4,000 FU/day. Vendor basis: NOW/iHerb, Vitacost, Life Extension, and Amazon marketplace; higher-FU softgels set premium pricing. Updated 2026-05-28.
How much you'd eat to match a supplemental dose.
Nattokinase activity is specific to natto fermentation and varies by product.
What to test, the optimal window inside the conventional range, and how long a response takes.
Nattokinase (2000 FU per day) modestly lowers fibrinogen and D-dimer in small RCTs and increases plasmin activity.7,1
Counsel on bleeding risk with anticoagulants and antiplatelets. Pair with fibrinogen and PT/INR if clinically relevant.
Nattokinase is expected to modestly lower fibrinogen, with effects that are typically small, dose-dependent, and clearest when baseline fibrinogen is elevated.7,1
Fasting is not strictly required, but draw at a consistent time of day since fibrinogen is an acute-phase reactant that rises with infection, inflammation, recent injury, or surgery. Avoid testing during acute illness. Note any anticoagulant or antiplatelet medications, as combining them with nattokinase raises bleeding risk and warrants clinician oversight.
Where this appears in the symptom-to-supplement map, ranked by relevance.
Nattokinase has fibrinolytic activity that may support healthy blood flow, though direct evidence for varicose veins specifically is very limited.1,2
Avoid with anticoagulants or bleeding risk, and recognize that evidence for venous insufficiency specifically is minimal.
Evidence-based stacks that include it, with the exact dose and timing each one uses.
Nattokinase is a fermented-soy enzyme studied for fibrinolytic activity and possible lipid-supportive effects, though the cardiovascular and lipid evidence in humans is still limited and emerging. Because it can affect clotting, it should be avoided or used only with clinician approval by anyone taking anticoagulant or antiplatelet medication.7,10
Documented cerebellar hemorrhage from nattokinase + aspirin after only 7 days. Both inhibit platelet aggregation via thromboxane blockade.
Recommendation: Do NOT combine without medical supervision. Higher risk in patients with cerebral microbleeds.
Both have fibrinolytic and antiplatelet activity; combined use additively raises bleeding risk.
Recommendation: Use together cautiously and only with surgical/bleeding-risk awareness. Avoid before procedures.
Both can reduce platelet aggregation or affect clotting, so combining them may additively increase bleeding risk.
Recommendation: Use caution when combining, especially if taking anticoagulant or antiplatelet drugs, and discontinue before surgery; consult a clinician.
Combining these two fibrinolytic enzymes produces additive breakdown of fibrin and a higher risk of bruising, prolonged bleeding, and (rarely) serious hemorrhage, particularly in people also on antiplatelet or anticoagulant drugs.
Recommendation: Avoid stacking both fibrinolytic enzymes unless supervised by a clinician. Stop both at least 1 to 2 weeks before any surgery or dental procedure, and do not combine with aspirin, warfarin, or DOACs without medical oversight.
Both have anticoagulant or antiplatelet activity, so combining them may increase bleeding risk, especially alongside blood-thinning medication.
Recommendation: Use caution when combining. Watch for bruising or bleeding, avoid if on anticoagulants without medical oversight, and discontinue before surgery.
Combining ginkgo with nattokinase increases bleeding risk because both reduce the blood's tendency to clot through different mechanisms.
Recommendation: Use the combination cautiously and avoid it if you take anticoagulants or antiplatelet drugs. Stop both at least 1 to 2 weeks before any surgery and report easy bruising or bleeding.
Garlic has antiplatelet activity and nattokinase has fibrinolytic activity, so combining them can additively impair clotting and raise bleeding risk, especially around surgery or with blood thinners.
Recommendation: Use together cautiously and monitor for easy bruising, nosebleeds, or prolonged bleeding. Stop both at least 7 to 10 days before surgery and avoid combining with anticoagulant or antiplatelet drugs without clinician oversight.
Both supplements independently lower the body's clotting capacity, Royal Jelly by potentiating anticoagulation (as shown in a warfarin case report) and Nattokinase through documented fibrinolytic and antiplatelet activity. Used together they can compound this effect, increasing the theoretical risk of easy bruising, prolonged bleeding, or more pronounced anticoagulation, especially in anyone also taking a blood thinner, aspirin, fish oil, or other antiplatelet supplement.
Recommendation: Most healthy adults not on blood thinners can use both, but watch for easy bruising, nosebleeds, bleeding gums, or prolonged bleeding from cuts. Do NOT combine without medical supervision if you take warfarin, a DOAC, aspirin, clopidogrel, or other antiplatelet/anticoagulant agents. Stop both at least 1 to 2 weeks before any surgery or dental extraction. If you choose to use both, keep Nattokinase at conservative doses (around 2,000 FU per day) and report any unusual bleeding to your clinician.
Nattokinase is a fibrinolytic enzyme that degrades fibrin directly and reduces clotting factors. Combined with warfarin, the additive effects substantially increase bleeding risk. Case reports describe hemoperitoneum and intracerebral hemorrhage with nattokinase in patients on other antithrombotics, and substituting nattokinase for warfarin has caused mechanical valve thrombosis.
Recommendation: Do not combine nattokinase with warfarin. Never substitute nattokinase for prescribed warfarin, especially after mechanical valve replacement or for atrial fibrillation. If you have started nattokinase, stop it and contact your anticoagulation clinic.
Nattokinase is a fibrinolytic enzyme that degrades fibrin and reduces clotting factor levels. Combined with apixaban's factor Xa inhibition, the additive effects substantially raise bleeding risk. Case reports describe intracerebral and intra-abdominal hemorrhage when nattokinase is added to other antithrombotics.
Recommendation: Do not combine nattokinase with apixaban. If you have been taking both, stop the nattokinase and call your prescriber, especially if you notice unusual bruising or bleeding.
Nattokinase is a direct fibrinolytic enzyme that also reduces clotting factor levels. Combined with rivaroxaban's factor Xa inhibition, the additive effect substantially raises bleeding risk. Reports describe intracerebral and intra-abdominal hemorrhage with nattokinase plus other antithrombotics.
Recommendation: Do not combine nattokinase with rivaroxaban. If you have been taking both, stop the nattokinase and contact your prescriber, especially if you notice any unusual bruising or bleeding.
Nattokinase is a fibrinolytic enzyme that directly degrades fibrin and reduces clotting factors. A documented case describes cerebellar hemorrhage in a patient with cerebral microbleeds who took aspirin plus nattokinase 400 mg/day for 7 days. The combination is particularly risky in patients with cerebral microangiopathy.
Recommendation: Avoid nattokinase while on aspirin, especially if you have a history of stroke, cerebral microbleeds, or uncontrolled hypertension. If you have been taking both, stop the nattokinase and call your prescriber.
Numbered references. Citations throughout the page link here.
Six RCTs (546 participants) showed nattokinase significantly reduced systolic BP by -3.45 mmHg and diastolic BP by -2.32 mmHg with no notable adverse events.
Zhang K, Zhang X, Wang A et al.. Nattokinase supplementation for cognitive enhancement in asymptomatic intracranial/carotid stenosis: A randomized controlled trial. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association. 2026
Liu M, Xu Z, Wang Z et al.. Lipid-lowering, antihypertensive, and antithrombotic effects of nattokinase combined with red yeast rice in patients with stable coronary artery disease: a randomized, double-blinded, placebo-controlled trial. Frontiers in nutrition. 2024
Nara N, Kurosawa Y, Fuse-Hamaoka S et al.. A single dose of oral nattokinase accelerates skin temperature recovery after cold water immersion: A double-blind, placebo-controlled crossover study. Heliyon. 2023
In 265 subjects over median 3 years, nattokinase 2,000 FU daily did not significantly differ from placebo in carotid intima-media thickness progression.
A supplement mixture containing nattokinase significantly improved HOMA-IR (insulin resistance index) and glycemic markers in prediabetic adults compared to placebo.
After 2 months of nattokinase administration, fibrinogen decreased 9%, factor VII 14%, and factor VIII 17% in healthy subjects.
8-week nattokinase trial showed net reductions of -5.55 mmHg in systolic and -2.84 mmHg in diastolic blood pressure vs control.
Cheng Y, Tong Y, Tao S et al.. Enhancing nattokinase stability through synergistic interactions:Construction and mechanism analysis of multi-level encapsulation structures in fig-like gel beads. Food research international (Ottawa, Ont.). 2026
Granito M, Alvarenga L, Ribeiro M et al.. Nattokinase as an adjuvant therapeutic strategy for non-communicable diseases: a review of fibrinolytic, antithrombotic, anti-inflammatory, and antioxidant effects. Expert review of cardiovascular therapy. 2024
Zhang F, Zhang J, Linhardt RJ. Interactions between nattokinase and heparin/GAGs. Glycoconjugate journal. 2015
Nattokinase was effective in managing atherosclerosis progression and hyperlipidemia in 1,062 participants.
Nattokinase improved clinical symptoms without adverse drug reactions or drug interactions in 153 patients with vascular diseases.
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