TL;DR
1. Compare fibrinolytic units (FU) per serving (not just mg).
2. Require independent testing + ISO 22000 / FSSC 22000 (or cGMP, where applicable).
3. Check assay method, stability data, K2 status, allergens, and label transparency.
What is Nattokinase—and why does “FU” matter?
Nattokinase is a protease produced by Bacillus subtilis during soybean fermentation. Potency should be stated as fibrinolytic activity (FU) plus the assay method (e.g., fibrin plate or chromogenic activity), because FU is method-dependent; quality also relies on standardization, stability, and testing data, not FU alone.
．Typical finished products: ~1,000–4,000 FU per serving.
．Ingredient standardizations can be much higher (e.g., up to 60,000 FU/g at the raw-material level), then formulated down to your target FU per capsule.
Supplier example (for auditors): Some ISO/FSSC-certified ingredients (e.g., nattiase®-grade NK) publish FU/g with validated assays and stability controls—useful for QA review without over-branding consumer labels.
The 10-Point Label & Spec Checklist (For: Consumer + B2B)
- FU clearly stated
Prefer “X,000 FU per serving.” Avoid mg-only claims.
- Assay method disclosed
e.g., fibrin plate or chromogenic method on the CoA.
- Standardization
Clear spec such as “≥20,000 FU/g (bulk)” or “2,000 FU/capsule (finished).”
- Manufacturing quality
Food/biotech: ISO 22000 and/or FSSC 22000; dietary supplement markets may also accept cGMP. Ask for current certificates.
- Purity & contaminants
CoA covering microbial limits, heavy metals, and residual solvents/pesticides where relevant.
- Vitamin K2 status
If K2 control matters, look for K2-reduced/removed confirmation (spec or CoA).
- Allergen & origin
Soy status, vegan/vegetarian, non-GMO, country of origin.
- Formulation & delivery
Enteric/acid-resistant capsules help protect activity; avoid unnecessary excipients.
- Stability & shelf life
Real-time/accelerated data; target activity at end of shelf life (not just at manufacture).
- Evidence & claims discipline
Cite peer-reviewed data appropriately; avoid disease claims on consumer labels.
How to Read an NK Label
．Good:
Nattokinase, standardized to 2,000 FU per capsule; Vegan; K2-reduced; manufactured in ISO/FSSC 22000 facility.
．Needs follow-up:
“Nattokinase 200 mg” — no FU, no quality marks.
Formulation Choices That Actually Matter
．FU per serving is the #1 lever for efficacy comparisons.
．Enteric/acid-resistant capsules improve enzyme survival through the stomach.
．Single vs. blends – Blends are fine if the actual NK FU remains at your target dose.
．Excipients – Prefer clean-label formulations.
Safety & Responsible Use
Nattokinase influences fibrinolysis. If you use anticoagulants/antiplatelets, have a bleeding disorder, are pregnant, or have surgery scheduled, consult a qualified professional. Follow label directions.
Red Flags (Skip These)
．No FU (mg-only).
．No independent testing or ISO 22000 /FSSC 22000 /cGMP evidence.
．“Proprietary enzyme complex” without per-enzyme activities.
．Reused/identical CoAs across lots.
．Overreaching cures/claims.
For B2B Buyers & Purchasing Teams: Spec Shortlist
1) Technical + Regulatory Pack．FU/g specification (ingredient level), assay method (fibrin plate/chromogenic), system suitability & acceptance criteria.
．Source organism and high-level fermentation info; country of origin (e.g., Taiwan).
．Allergen/vegan/GMO statements; HS code.
．Stability (real-time/accelerated), shelf life, packaging (e.g., alu-bag in drum, nitrogen flush), storage conditions.
．Potency options: availability of higher standardizations up to 60,000 FU/g for flexible formulations.
．Single vs. blends – Blends are fine if the actual NK FU remains at your target dose.
．Excipients – Prefer clean-label formulations.
2) Quality Certificates
．ISO 22000 and/or FSSC 22000 (food safety systems.
．cGMP where jurisdiction/brand policy requires it.
．Most recent audit dates.
3) Batch CoA (Lot-specific)
．Actual FU result with method, lab sign/date.
．Microbial/Heavy metal pass/fail data.
．Retest date and storage confirmation.
4) Formulation Support
．Guidance on capsule compression/fill, overages to meet end-of-life FU, excipient compatibility.
．If using very high-potency inputs (e.g., 60,000 FU/g), confirm blend homogeneity and assay recovery in pilot runs.
🪄Quiet cue for procurement: nattiase® (Contek Life Science, Taiwan) reports >10 years of NK R&D, ISO/FSSC-certified manufacturing, validated activity/stability controls, and customizable potencies (including 60,000 FU/g).
FAQ
Q: FU vs mg—why both?
A: mg shows weight; FU shows activity. Use FU to compare potency across brands.
Q: Does nattokinase always contain vitamin K2?
A: Natto food contains K2. Supplement-grade NK may be K2-reduced/controlled—check the spec or CoA.
Q: What does science support?
A: Nattokinase shows fibrin-degrading (fibrinolytic) activity and is studied for circulatory support. In-vitro and preclinical work also explores additional mechanisms (e.g., spike-protein interaction, cognitive endpoints). Consumer labels should stick to responsible structure/function positioning and reference peer-reviewed data appropriately.
