What Is Nattokinase?
Nattokinase is a proteolytic (protein-dissolving) enzyme extracted from natto — a traditional Japanese fermented soybean food. The bacterium Bacillus subtilis var. natto produces this enzyme during fermentation. Discovered in 1987 by Japanese researcher Dr. Hiroyuki Sumi, nattokinase has since attracted over 100 scientific studies.
Its defining property: it breaks down fibrin — the protein that forms the structural "scaffold" of blood clots. This makes it one of the very few dietary supplements with a direct mechanism of action on the clotting system.
Who Is This Guide For?
If you are concerned about vascular health, blood pressure, or circulation and want an evidence-based overview of what nattokinase can actually do, this guide gives you the clear picture.
TL;DR
- Nattokinase is a fibrinolytic enzyme that breaks down fibrin (blood clot protein)
- Standard dose: 2,000 FU (fibrinolytic units) daily, on an empty stomach
- Moderate evidence for blood pressure reduction (~5 mmHg systolic) (Kim et al., 2008)
- Critical warning: Do NOT use with blood thinners (warfarin, aspirin, clopidogrel)
- Effects appear within 4-8 weeks
- Soy allergy — check if the product is soy-free (purified nattokinase)
How Nattokinase Works
Nattokinase affects the blood clotting system from multiple angles:
1. Direct fibrinolysis
Directly breaks down fibrin — the protein forming blood clot structure. This is a rare property among dietary supplements (Sumi et al., 1987).
2. tPA activation
Stimulates the body's own tissue plasminogen activator (tPA), enhancing natural fibrinolysis (Fujita et al., 1995).
3. PAI-1 reduction
Reduces plasminogen activator inhibitor-1, which normally suppresses fibrinolysis.
In summary: nattokinase helps the body clear fibrin more efficiently, which theoretically reduces blood clot risk.
What the Evidence Says
Moderate Evidence
Blood pressure reduction: Kim et al. (2008) conducted a randomized controlled trial with 86 participants and found that 2,000 FU of nattokinase daily reduced systolic blood pressure by an average of 5.55 mmHg over 8 weeks. A meta-analysis (Ren et al., 2017) confirmed similar results.
Fibrinolytic activity: Kurosawa et al. (2015) showed in healthy volunteers that a single 2,000 FU dose significantly increased blood fibrinolytic activity for 2-8 hours.
Preliminary Evidence
- Deep vein thrombosis (DVT) prevention: A small pilot study on flights suggested reduced leg swelling risk during long flights
- Atherosclerosis slowing: One study suggested reduced carotid intima-media thickness over 6 months
- Cholesterol effects: Limited data, conflicting results
Weak / No Evidence
- Stroke prevention — no large clinical trials exist
- Alzheimer's prevention — theoretical, no clinical data
- Muscle soreness, inflammation — unconvincing results
Dosage and Protocol
| Goal | Dose (FU) | Timing | Notes |
|---|---|---|---|
| General cardiovascular support | 2,000 FU/day | Empty stomach, morning | Standard dose in studies |
| Blood pressure support | 2,000 FU/day | Morning, empty stomach | 8+ weeks before assessment |
| Higher dose | 4,000 FU/day | Split into 2 doses | Only with medical consultation |
FU = fibrinolytic unit. This is the specific unit measuring nattokinase activity. Do not confuse it with milligrams — 100 mg of nattokinase does not mean 100 FU.
Practical protocol:
1. Start with 2,000 FU in the morning on an empty stomach
2. Take 30 minutes before eating, with water
3. Evaluate blood pressure effects after 8 weeks
4. Monitor blood pressure at home regularly to track results
Choosing Quality Products
| Feature | High quality | Low quality |
|---|---|---|
| Activity label | FU (fibrinolytic units) | Only mg |
| Certification | NSF/GMP/JNKA | None |
| Vitamin K2 content | Removed (K2-free) | Unmarked |
| Soy allergens | Clearly labeled | Unmarked |
| Enteric coating | Preferred (protects from stomach acid) | None |
Important detail: Traditional natto also contains vitamin K2, which affects blood clotting. Pure nattokinase extract should be K2-free, especially if you use blood thinners.
Interactions and Safety
Do NOT use with:
- Warfarin/coumarins — double thinning, bleeding risk
- Daily aspirin — increased bleeding risk
- Clopidogrel (Plavix) — increased bleeding risk
- Other anticoagulants — heparin, rivaroxaban, etc.
Stop 2 weeks before surgery and inform your surgeon about nattokinase use.
Common Mistakes
1. Eating natto instead of taking nattokinase — natto has good nutritional value, but nattokinase content varies between batches. A standardized supplement is more reliable.
2. Confusing FU and mg — always look for FU labeling, not just milligrams.
3. Combining with blood thinners — this is a serious risk, not a "natural alternative" to use alongside.
4. Setting unrealistically high expectations — nattokinase supports circulation, but does not replace lifestyle changes or medications.
Frequently Asked Questions
Does nattokinase replace blood thinners?
No. Nattokinase is a dietary supplement, not a medication. Never replace prescription drugs with nattokinase without your doctor's consent.
Is nattokinase safe for people with soy allergy?
Purified nattokinase extract is typically free of soy proteins, but trace amounts may be present. Severely allergic individuals should be cautious and check manufacturer data.
Does nattokinase help with cholesterol?
Data is conflicting and limited. Nattokinase's primary area of effect is fibrinolysis and blood pressure, not cholesterol.
When is the best time to take nattokinase?
Morning on an empty stomach, 30 minutes before eating. Some studies suggest greater fibrinolytic activity at night, so an evening dose is also an option.
Is nattokinase suitable for vegans?
Yes — nattokinase originates from plant-based fermentation and is vegan-friendly. Check capsule material.
Estonia-Specific Considerations
In Estonia, cardiovascular disease is the leading cause of death (nearly 50% of all deaths). Blood pressure monitoring and preventive health measures are especially important. Nattokinase products are available in Estonia mainly through supplement shops, at approximately 15-30 EUR/month (60-90 capsules).
Since Estonian winters are cold and people spend extended periods sitting indoors, circulation issues are common. Nattokinase can be one component of a broader cardiovascular plan alongside exercise, omega-3 fatty acids, and healthy lifestyle habits.
References
1. Sumi H, Hamada H, Tsushima H, et al. (1987). A novel fibrinolytic enzyme (nattokinase) in the vegetable cheese Natto; a typical and popular soybean food in the Japanese diet. Experientia, 43(10), 1110-1111.
2. Kim JY, Gum SN, Paik JK, et al. (2008). Effects of nattokinase on blood pressure: a randomized, controlled trial. Hypertension Research, 31(8), 1583-1588.
3. Fujita M, Nomura K, Hong K, et al. (1995). Purification and characterization of a strong fibrinolytic enzyme (nattokinase) in the vegetable cheese natto. Biochemical and Biophysical Research Communications, 197(3), 1340-1347.
4. Kurosawa Y, Nirengi S, Homma T, et al. (2015). A single-dose of oral nattokinase potentiates thrombolysis and anti-coagulation profiles. Scientific Reports, 5, 11601.
5. Ren NN, Chen HJ, Li Y, et al. (2017). A clinical study on the effect of nattokinase on carotid artery atherosclerosis and hyperlipidaemia. Chinese Medical Journal, 97(26), 2038-2042.
6. Jensen GS, Lenninger M, Ero MP, et al. (2016). Consumption of nattokinase is associated with reduced blood pressure and von Willebrand factor, a cardiovascular risk marker. Integrated Blood Pressure Control, 9, 95-104.
See also:
- Weights: Complete Guide 2026
- High-Fiber Foods: Why Fiber Is an Athlete's Best Friend
- Methylene Blue: An Old Drug with New Potential for Brain Health
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