Supplement analysis backed by scientific evidence · PT

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Limited evidenceHeart & metabolic

Nattokinase

Nattokinase is a fibrin-degrading enzyme from fermented soy with plausible mechanism and small positive trials, but the human evidence base is small, geographically narrow and short-term. The bleeding-risk questions are more concrete than the benefits.

What the science says

  • Lowers blood pressure Limited evidence

    A randomised controlled trial in 86 adults with pre-hypertension found 2,000 FU/day for 8 weeks reduced systolic blood pressure by about 5.6 mmHg and diastolic by about 2.8 mmHg versus placebo. A 2023 systematic review and meta-analysis of nattokinase RCTs found similarly modest reductions, but the pooled trial count is small and nearly all trials come from East Asia with short follow-up.

  • Improves lipid profile Limited evidence

    Meta-analysed trials show small reductions in total cholesterol and LDL, but several of the positive studies combined nattokinase with red yeast rice or other actives, making the independent contribution of nattokinase impossible to isolate.

  • Fibrinolytic and anti-thrombotic activity Limited evidence

    Nattokinase demonstrably degrades fibrin in vitro and modestly alters fibrinolytic markers such as D-dimer and euglobulin lysis time after oral dosing. Whether an orally administered protease survives digestion in quantities sufficient to affect clinically meaningful thrombosis remains unresolved — there are no trials with clot or stroke endpoints of adequate size and quality.

  • Reduces carotid plaque Limited evidence

    A single trial reported reduced carotid intima-media thickness and plaque size over 6-12 months. It has not been independently replicated, and imaging-based endpoints in unblinded or single-centre settings are easily overstated.

Dosage & safety

Studied doseTrials used 2,000-4,000 FU/day (fibrinolytic units) — commonly 100-200 mg of extract standardised to 2,000 FU per 100 mg — taken once daily, often in the evening, for 8 weeks to 6 months. Note that FU, not milligrams, is the meaningful unit; products labelled only in mg are uninformative. Natto food itself contains vitamin K2 (MK-7), whereas most supplements are vitamin K-depleted; check which one you have.
SafetyThe main concern is bleeding. Because nattokinase has fibrinolytic activity, it should not be combined with warfarin, DOACs, heparin, aspirin or clopidogrel without medical supervision, and should be stopped at least 2 weeks before surgery or dental extraction. Case reports of intracerebral haemorrhage in users on antiplatelet therapy exist. Avoid in people with active bleeding, peptic ulcer, recent stroke or bleeding disorders. Soy-allergic individuals should avoid it. Some products retain vitamin K2, which would antagonise warfarin in the opposite direction — an unpredictable combination. Avoid in pregnancy and breastfeeding. Long-term safety data beyond 6 months are lacking.

Scientific references

Where to buy

Nutricost, Nattokinase, 100 mg (2,000 FU), 120 Capsules

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