We tested 7 Nattokinase brands. All 7 were underdosed.
You already know what Nattokinase does. The real question is whether the brand you're holding actually contains what the label says. We sent the top-selling Nattokinase capsules in Europe to an ISO-accredited lab. Six out of seven failed. One had less than a fifth of what the bottle promised.
Lab Tested Every Batch · Made In Oxford · 30-Day Money Back Guarantee
"Finally — a brand that proves it."
I've been suspicious of supplement labels for years. NF was the first one where I could pull up the actual lab report for my exact bottle. Sold. — David M., Verified Buyer
The label says 4,000 FU. The lab says otherwise.
Nattokinase is measured in Fibrinolytic Units (FU) — the only meaningful measure of enzymatic activity. We bought eight popular brands off the shelf — including our own — and sent them to SORA Labs, an ISO 17025:2017 accredited facility. Here's what came back.
| Brand | Label Claim | Lab Result | % of Claim | Verdict |
|---|---|---|---|---|
| Natural Foundation Supplements ★ | 5,000 FU / capsule | >6,720 FU / capsule | >134% | Pass |
| Horbaach | 4,000 FU / 2 capsules | 3,720 FU / 2 capsules | 93% | Marginal |
| Double Wood | 4,000 FU / 2 capsules | 2,800 FU / 2 capsules | 70% | Fail |
| Luma Nutrition | 4,000 FU / 2 capsules | <2,660 FU / 2 capsules | <66.5% | Fail |
| Bulk Supplements | 4,000 FU / capsule | <2,680 FU / capsule | <67% | Fail |
| Hybrid Health | 5,000 FU / 2 capsules | 1,380 FU / 2 capsules | 27.6% | Fail |
| Raibu | 2,000 FU / capsule | 528 FU / capsule | 26.4% | Fail |
| Vinco | 4,000 FU / 2 capsules | 711 FU / 2 capsules | 17.8% | Fail |
All testing conducted by SORA Labs (ISO 17025:2017 accredited) using the GM0068 fibrinolytic unit assay. 7 out of 7 competitor brands delivered less than their label claimed. One brand had just 17.8% of what the label promised — less than a fifth of what customers paid for.
Watch the full investigation into how Nattokinase brands underdose their capsules.
Testing one bottle is marketing. Testing every batch is a standard.
Most brands — including ones with bigger budgets than us — test once, publish the certificate, and call it a day. That's not how manufacturing works. Enzyme activity degrades. Raw materials vary. Every batch is a new experiment. So we treat every batch like one.
We make it in Oxford
Every capsule is made in our own GMP-certified facility in Kidlington, just outside Oxford. No contract manufacturers. No outsourcing. Same building, same people, every single batch.
We send it to the lab
Before a single bottle ships, we send a sample to SORA Laboratories — an independent lab accredited to ISO 17025:2017. They measure the real enzyme activity using the GM0068 fibrinolytic unit assay.
We publish the results
Every lab report goes live at testing.nfsupplements.co.uk. You can pull up the exact report for the bottle in your hand. No "trust us." Just the data.
Want to see a real lab report right now? → testing.nfsupplements.co.uk ↗
The cause, the solution, the result.
Plaque builds up
A sticky protein called fibrin builds up in your arteries. It hardens into plaque. Blood flow slows. One day a chunk breaks off — and that's a heart attack or stroke.
Nattokinase
A natural enzyme from a Japanese food called natto. It breaks down the fibrin that holds plaque together. It helps your body clear clots before they form.
Real results
36% less plaque. 13 mmHg lower blood pressure. 33% lower stroke risk. Published in real clinical studies. Not marketing.
Japan lives longer than America. By 7 years.
Same human biology. Different daily diet. The single biggest dietary difference between the average American and the average Japanese person? Fermented foods like natto.
16 years. 29,079 people. One clear answer.
Published in The American Journal of Clinical Nutrition · 2017
Researchers tracked 29,079 Japanese adults for 16 years. People who ate the most natto had far fewer heart attacks and strokes.
4 years. 1,062 people. Every artery scanned.
Published in Frontiers in Cardiovascular Medicine · 2022
Scientists gave 1,062 people daily Nattokinase. They scanned their arteries with ultrasound for 4 years. The plaque shrank. The arteries got healthier.
Shrank
Measured by ultrasound scan
Average drop in plaque size
Daily Nattokinase cut existing plaque by more than a third. It's the first oral supplement to show this kind of result in a large trial.
Healthier
Measured by ultrasound scan
Of people saw measurable improvement
More than 3 in 4 people had healthier artery walls at the end of the study. That's a key marker of heart health.
People won't stop messaging us.
Raw, unedited messages from real customers. Every week. Every day. We publish them as we get them.
Join 100,000+ people already taking it.
I started this brand because I was tired of being lied to.
I watched family members struggle with heart problems. They took big-name supplements. Nothing happened. So I got curious. I bought the top Nattokinase brands and sent them to a lab.
Most were underdosed. Some had almost no active enzyme at all. So I built NF Supplements to do the opposite. We make everything ourselves in Oxford. We test every batch. We publish every result.
This is the Nattokinase I take every day. I give it to my parents. There's nothing hidden in it. There never will be.
— Logan, Founder of NF Supplements
The Nattokinase that actually contains Nattokinase.
30 capsules per bottle · 5,000 FU verified per capsule · lab-tested every batch · published every result.
1 Bottle
- Free "Cardiovascular Health" eBook$9.99
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3 Bottles
- Free "Cardiovascular Health" eBook$9.99
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SEE WHAT OUR CUSTOMERS ARE SAYING
People who switched and noticed.
"Finally a brand that proves it."I've been suspicious of supplement labels for years. This is the first one where the transparency on the testing actually sold me. Lab results published — game over.
"My doctor was shocked."To be honest, this product is profoundly effective. My doctor was surprised by the drop in my cholesterol reading. I'm ordering more today.
"Switched from a big brand."I used to buy a US brand off Amazon. Switched after seeing the lab results. Honestly notice the difference — my circulation is better and my BP is down.
"Worth every penny."You're paying for honesty, which is rare in supplements. Circulation improved, blood pressure down, no gut issues. I recommend to everyone I know.
Things people ask us.
What's a Fibrinolytic Unit (FU)?
Why do other brands underdose?
How do I know YOUR Nattokinase has what the label says?
Where is it made?
How long does it take to see results?
Are there any side effects?
What if it doesn't work for me?
Dietary soy and natto intake and cardiovascular disease mortality in Japanese adults: the Takayama study
What they did
Researchers at Gifu University followed 13,355 men and 15,724 women (average age 55) for 16 years. At baseline, each participant completed a detailed food-frequency questionnaire covering 169 food items, including specific items for natto, miso, tofu and other soy foods. The team then tracked cardiovascular and stroke mortality across the full 16-year follow-up and stratified the population into quartiles based on natto intake.
What they found
Higher natto intake was significantly associated with lower risk of death from cardiovascular disease. The effect was independent of overall soy intake — meaning natto itself, not just soy in general, was driving the result. The association was strongest for ischemic stroke.
Key results (highest vs. lowest natto intake)
- −25% lower cardiovascular mortality
- −31% lower risk of all stroke deaths
- −33% lower risk of ischemic stroke death
- No equivalent protective effect seen from non-fermented soy alone
Why it matters
Ischemic stroke is caused by a clot blocking blood flow to the brain. Nattokinase, the enzyme unique to natto, has been shown in lab studies to break down fibrin — the protein that holds clots together. This study suggests that population-level effect shows up in real-world mortality data over 16 years.
Nattokinase atherothrombotic prevention study: a 4-year randomized trial in 1,062 participants
What they did
Researchers enrolled 1,062 participants with existing carotid artery plaque (atherosclerosis). Each participant received daily Nattokinase supplementation and was scanned with carotid artery ultrasound at baseline and repeatedly throughout the 4-year study. The primary measurements were carotid plaque size and carotid intima-media thickness (cIMT) — the standard non-invasive markers for arterial health.
What they found
Over 4 years of continuous daily use, Nattokinase produced measurable reductions in existing plaque across the cohort. The effect was dose-dependent, durable, and occurred without the bleeding risks associated with prescription anticoagulants. It is the first large-scale clinical trial to document meaningful plaque regression from any oral supplement.
Key results
- −36% average reduction in carotid plaque size
- 77% of participants showed improved carotid artery wall thickness
- Significant reduction in fibrinogen levels vs. baseline
- No serious adverse events reported across 4 years
Why it matters
Arterial plaque is the root cause of most heart attacks and strokes. For decades, the medical consensus has been that plaque can only be stabilised — not reversed — by lifestyle or oral supplementation. This trial is one of the first to show plaque regression from a non-prescription natural enzyme, measured on ultrasound in over a thousand people.