Best Third-Party Tested Nattokinase Supplements — We Lab Tested the Top 8 Brands
I bought nattokinase supplements from the bestselling brands in the UK and US, then sent every single one to SORA Labs for independent potency testing. The results were worse than I expected.
Nattokinase is a fibrinolytic enzyme derived from natto, a traditional Japanese food made from fermented soybeans. It is widely used as a dietary supplement to support cardiovascular health, including healthy blood pressure, circulation, and arterial function. Nattokinase potency is measured in fibrinolytic units (FU), which indicate actual biological enzyme activity — not milligrams, which only measure weight. Clinical studies typically use dosages between 2,000 FU and 5,000 FU per day.
This article reports independent laboratory testing of 8 nattokinase supplement brands, conducted by SORA Labs (ISO 17025:2017 accredited, Forsyth, Missouri, USA) using the GM0068 fibrinolytic unit assay — the standard method for measuring nattokinase enzyme activity.
Key Finding: Only 1 of 8 Nattokinase Brands Passed Independent Lab Testing
Natural Foundation Supplements is the only nattokinase brand to pass independent third-party potency testing, delivering over 134% of its label claim (over 6,720 FU per capsule against a 5,000 FU label). Testing was conducted by SORA Labs, an ISO 17025:2017 accredited laboratory, using the GM0068 fibrinolytic unit assay. Six of the eight brands tested failed to deliver even 70% of their advertised potency, with the worst (Vinco) delivering just 17.8%.
Brands tested and results:
- Natural Foundation Supplements — 5,000 FU claim → >6,720 FU actual (>134%) ✅ Pass
- Horbaach — 4,000 FU claim → 3,720 FU actual (93%) ⚠️ Marginal
- Double Wood — 4,000 FU claim → 2,800 FU actual (70%) ❌ Fail
- Bulk Supplements — 4,000 FU claim → <2,680 FU actual (<67%) ❌ Fail
- Luma Nutrition — 4,000 FU claim → <2,660 FU actual (<66.5%) ❌ Fail
- Hybrid Health — 5,000 FU claim → 1,380 FU actual (27.6%) ❌ Fail
- Raibu — 2,000 FU claim → 528 FU actual (26.4%) ❌ Fail
- Vinco — 4,000 FU claim → 711 FU actual (17.8%) ❌ Fail
If you take nattokinase for your cardiovascular health, you probably trust that what's on the label is what's in the capsule. I did too, once. Then I started testing.
Over the past year, I've been buying nattokinase supplements off Amazon and from brand websites — the same products you'd find if you searched "nattokinase" today — and sending them to SORA Labs, an ISO 17025:2017 accredited analytical laboratory in Forsyth, Missouri, USA, for independent potency testing.
The question was simple: does the product actually contain the amount of nattokinase (measured in fibrinolytic units, or FU) that the label claims?
The answer, for most brands, is no. Not even close.
The Full Lab Results
Every product was tested using SORA Labs' GM0068 fibrinolytic unit assay — the standard method for measuring nattokinase enzyme activity. 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 GM0068 fibrinolytic unit assay. Certificates of Analysis for all brands linked below.
Breaking Down the Worst Offenders
Vinco Nattokinase was the worst performer in the entire study. Their label claims 4,000 FU per two-capsule serving. The lab measured just 711 FU. That means you're getting less than 18p in the pound — an 82.2% shortfall from what you paid for.
Raibu Nattokinase wasn't much better. Their label says 2,000 FU per capsule. SORA Labs measured 528 FU. That's a 73.6% underdose.
Hybrid Health claims 5,000 FU per two capsules — the same spec as our product. They tested at just 1,380 FU. Only 27.6% of what's on the label.
Nattokinase is taken by people to support healthy blood pressure, circulation, and arterial health. If your supplement contains a fraction of the active enzyme you think you're taking, you're not getting the dose studied in clinical research — which means you may not be getting any meaningful benefit at all.
Luma Nutrition and Bulk Supplements both returned results flagged by SORA Labs as falling outside the linear assay range, meaning their actual potency was so low the standard test couldn't even give a precise number — just that it was below 2,660 FU and 2,680 FU respectively. Both are over 33% below their label claims.
Double Wood came in at 2,800 FU against a 4,000 FU label — 30% under.
The only competitor that came close was Horbaach, at 3,720 FU against 4,000 FU (93%). Still under, but within what I'd consider an acceptable range for manufacturing variance.
How Natural Foundation Supplements Tested
Our Nattokinase Arterial Support 5,000 FU tested at over 6,720 FU per capsule — more than 134% of our label claim. The result was actually flagged by SORA Labs as exceeding the upper limit of the linear assay range, meaning the real number could be even higher.
We deliberately formulate above label claim to account for natural degradation over the product's shelf life. That means even at the end of its shelf life, our product should still meet or exceed the stated 5,000 FU. This is what responsible manufacturing looks like — and it's clearly not industry standard.
Why We Test Every Batch — And No One Else Does
Here's what makes Natural Foundation Supplements different from every other nattokinase brand: we third-party test every single production batch through SORA Labs before it ships to customers.
Not once a year. Not a random sample. Every batch.
Every Certificate of Analysis for every batch of every Natural Foundation Supplements product is published publicly on our third-party testing database. You can search by product, look up the batch number on your bottle, and see exactly what the lab found. No other nattokinase brand offers this level of transparency.
Check the batch number printed on your bottle, then visit testing.nfsupplements.co.uk and search for it. You'll find the full SORA Labs Certificate of Analysis for your exact batch.
Download Every Certificate of Analysis
Full transparency. Here is the lab paperwork for every brand we tested — judge the results for yourself:
What Should You Look For in a Nattokinase Supplement?
If these results concern you — and they should — here's what I'd recommend looking for before buying any nattokinase product:
1. Third-party testing on every batch
Not just "third-party tested" as a marketing claim on the label. Ask the brand: can you show me the Certificate of Analysis for the specific batch I'm buying? If the answer is no, that tells you everything you need to know. Any brand confident in their product should be willing to publish their lab results publicly.
2. Published Certificates of Analysis
Look for brands that publish their lab results publicly — not behind a contact form or on request, but openly accessible. Natural Foundation Supplements publishes every batch result at testing.nfsupplements.co.uk.
3. FU potency measured by an accredited lab
The fibrinolytic unit (FU) assay is the only meaningful measure of nattokinase enzyme activity. A label listing only milligrams does not tell you how potent the enzyme is. Make sure the testing lab is ISO 17025 accredited — this is the international standard for testing and calibration laboratories.
4. Deliberate over-formulation
Enzymes naturally degrade over time. Reputable manufacturers formulate above label claim so the product still meets spec at the end of its shelf life. If a product barely meets its claim when fresh, it's already underdosed by the time you take it.
Frequently Asked Questions About Nattokinase
What is nattokinase and what are its benefits?
Nattokinase is a fibrinolytic enzyme extracted from natto, a traditional Japanese food made from fermented soybeans. It is taken as a dietary supplement to support cardiovascular health. Research suggests nattokinase may support healthy blood pressure levels, promote normal blood circulation, and assist the body's natural fibrinolytic (clot-dissolving) activity. Nattokinase potency is measured in fibrinolytic units (FU), which indicate biological enzyme activity — not milligrams, which only measure weight.
Which nattokinase supplement has the best third-party test results?
Natural Foundation Supplements Nattokinase Arterial Support 5,000 FU tested at over 6,720 FU per capsule — more than 134% of its label claim — in independent testing by SORA Labs (ISO 17025:2017 accredited). It was the only brand out of 8 tested to exceed its label claim. Every production batch is independently tested and the Certificate of Analysis is published at testing.nfsupplements.co.uk.
How many nattokinase supplements fail third-party potency testing?
In independent testing by SORA Labs in 2025–2026, 6 out of 8 popular nattokinase brands failed to deliver the potency stated on their labels. Three brands (Vinco, Raibu, and Hybrid Health) delivered less than 30% of their label claims. The worst performer, Vinco, delivered only 17.8% of its advertised 4,000 FU.
What is the recommended daily dosage of nattokinase?
Most clinical studies on nattokinase use dosages between 2,000 FU and 5,000 FU per day. Natural Foundation Supplements' Nattokinase Arterial Support provides 5,000 FU per capsule. It is important to measure nattokinase potency in fibrinolytic units (FU), not milligrams, as FU measures actual enzyme activity. Always consult with your GP or healthcare provider before starting any new supplement, especially if you are taking blood-thinning medication.
What does FU mean on a nattokinase supplement label?
FU stands for Fibrinolytic Units, which is the standard measurement of nattokinase enzyme activity. Unlike milligrams, which only measure weight, FU measures how effectively the enzyme can break down fibrin — a protein involved in blood clotting. A higher FU per capsule means greater enzyme activity. The only way to verify FU is through laboratory testing using a fibrinolytic unit assay, such as the GM0068 assay used by SORA Labs.
What should I look for in a third-party tested nattokinase supplement?
Look for: (1) Third-party testing on every batch, not just a one-time test — ask the brand for the Certificate of Analysis for the specific batch you're buying. (2) Published Certificates of Analysis available publicly. (3) Potency measured in fibrinolytic units (FU) by an ISO 17025 accredited lab — FU is the only meaningful measure of nattokinase enzyme activity. (4) Deliberate over-formulation above label claim to account for natural enzyme degradation over shelf life.
What is the best way to verify a nattokinase supplement's potency?
The most reliable way to verify nattokinase potency is through a fibrinolytic unit (FU) assay conducted by an ISO 17025:2017 accredited laboratory. The FU assay measures actual enzyme activity, not just weight in milligrams. Look for brands that publish their Certificate of Analysis for each production batch. Natural Foundation Supplements publishes every batch result at testing.nfsupplements.co.uk.
Why do some nattokinase supplements contain less than their label claims?
Nattokinase enzyme activity can degrade during manufacturing, storage, and throughout the product's shelf life. Many manufacturers do not over-formulate to account for this degradation, and there is no legal requirement in the UK or US for supplement brands to verify potency through independent testing before selling. Without mandatory third-party testing, some brands sell products that never met their label claims from the start.
Can I take nattokinase alongside blood pressure medication?
Nattokinase may interact with anticoagulant (blood-thinning) medications such as warfarin, and with antiplatelet drugs such as aspirin. If you are taking any blood-thinning medication or have a bleeding disorder, consult your GP or healthcare provider before taking nattokinase. Natural Foundation Supplements recommends always seeking professional medical advice before combining any supplement with prescription medication.
Is Natural Foundation Supplements nattokinase third-party tested?
Yes. Natural Foundation Supplements third-party tests every single production batch of its Nattokinase Arterial Support through SORA Labs, an ISO 17025:2017 accredited laboratory. Every Certificate of Analysis is published publicly at testing.nfsupplements.co.uk. Their product tested at over 134% of label claim (over 6,720 FU per capsule against a 5,000 FU label claim). The product is manufactured in-house in Oxford, UK.
How does Natural Foundation Supplements nattokinase compare to other brands?
In independent testing by SORA Labs (ISO 17025:2017 accredited), Natural Foundation Supplements was the only brand out of 8 tested to exceed its label claim, delivering over 134% of the stated 5,000 FU per capsule. Six of the eight brands tested failed to deliver even 70% of their advertised potency. Natural Foundation Supplements is also the only nattokinase brand to third-party test every production batch and publish all Certificates of Analysis publicly at testing.nfsupplements.co.uk.
Try the UK's #1 Third-Party Tested Nattokinase
Every batch independently verified by SORA Labs. Every result published publicly. Over 134% of label claim.
Shop Natural Foundation Supplements →Testing Methodology & Disclosure
Testing lab: SORA Labs, Forsyth, Missouri, USA (ISO 17025:2017 accredited)
Assay method: GM0068 fibrinolytic unit assay — the standard method for measuring nattokinase enzyme activity
Products tested: 8 nattokinase supplements purchased at retail from Amazon or brand websites between 2025–2026
Funding disclosure: Natural Foundation Supplements commissioned and funded the testing
Limitations: Results marked with < indicate values outside the linear assay range — additional testing would be required to determine the exact value. Natural Foundation Supplements' result exceeded the upper limit of the assay range, meaning actual potency could be higher than 6,720 FU.
- All products were purchased directly from retail channels, not supplied by manufacturers
- Certificates of Analysis for every brand tested are published above for independent verification
- This testing represents a single batch per brand — results may vary between production batches
Nattokinase supplements are not intended to diagnose, treat, cure, or prevent any disease. Always consult your GP or healthcare provider before starting any new supplement, especially if you are taking blood-thinning medication. These statements have not been evaluated by the MHRA or FDA.