Nattokinase, a fermented-soybean enzyme sold as a supplement for heart and blood vessel health, breaks down the protein mesh of blood clots. Human evidence is thin: the most consistent signal is a modest blood pressure fall when pressure is already raised. Artery plaque and cholesterol claims lack proper comparison groups; prevention of heart attack, stroke, or early death is untested. Bleeding is the main concern; benefit-risk balance remains uncertain. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Blood pressure | Change from own baseline average (no established target for nattokinase use) | Expected to change (modest fall when raised) |
| PT/INR | 0.8–1.2 | Safety check: a rise signals bleeding risk |
| aPTT | 25–35 seconds | Safety check: nattokinase prolonged it in a trial |
| Hemoglobin | Men 13.5–17.5 g/dL; women 12.0–15.5 g/dL | Safety check: a fall suggests hidden bleeding |
| Platelet count | 150–450 × 10⁹/L | Safety check: low counts raise bleeding risk |
| LDL cholesterol | Change from own baseline (no established target for nattokinase use) | Expected to change only at high doses |
| Fibrinogen | 200–400 mg/dL | Expected to change (modest fall) |
Cadence: Baseline before starting; blood pressure weekly for the first month, then every 3 months; clotting tests at 4 weeks, then every 3–6 months with anticoagulant or antiplatelet drugs; complete blood count every 6–12 months; lipids at 3 months, then every 6–12 months on high-dose regimens