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.
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 the US, 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 ★ | 5,000 FU / cap | >6,720 FU / cap | >134% | Pass |
| Horbaach | 4,000 FU / 2 caps | 3,720 FU / 2 caps | 93% | Marginal |
| Double Wood | 4,000 FU / 2 caps | 2,800 FU / 2 caps | 70% | Fail |
| Luma Nutrition | 4,000 FU / 2 caps | <2,660 FU / 2 caps | <66.5% | Fail |
| Bulk Supplements | 4,000 FU / cap | <2,680 FU / cap | <67% | Fail |
| Hybrid Health | 5,000 FU / 2 caps | 1,380 FU / 2 caps | 27.6% | Fail |
| Raibu | 2,000 FU / cap | 528 FU / cap | 26.4% | Fail |
| Vinco | 4,000 FU / 2 caps | 711 FU / 2 caps | 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 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 us 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 NF 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.
2. Published Certificates of Analysis
Any brand confident in their product should be willing to publish their lab results publicly. We do this at testing.nfsupplements.co.uk for every batch we produce.
3. FU potency measured by an accredited lab
The fibrinolytic unit (FU) assay is the only meaningful measure of nattokinase enzyme activity. 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.
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 NF Supplements →About this test: All products were purchased at retail from Amazon or brand websites between 2025–2026. Testing was conducted by SORA Labs (Forsyth, Missouri, USA), an ISO 17025:2017 accredited laboratory, using the GM0068 fibrinolytic unit assay method. Natural Foundation Supplements commissioned and funded the testing. Results marked with * or < indicate values outside the linear assay range — additional testing would be required to determine the exact value, meaning actual potency could be even lower (or higher, in NF's case) than reported.