The first sign that something strange was happening came from our own customer service inbox. In late February, we started getting messages from people asking why our Nattokinase Arterial Support cost £59.99 on eBay when our website listed it at £29.99. They wanted to know if the eBay version was a different formula. A different strength. A counterfeit, even.
It wasn't. It was ours. The tubs were genuine. The expiry dates checked out. The batches matched our records. Someone was just buying our nattokinase from us at full retail and reselling it on eBay at roughly double the price.
By the time we'd worked out what was going on, there were already dozens of listings live. Some sellers had moved hundreds of bottles. And, because of the demand we were dealing with at the time, we kept selling out. Resellers were quietly taking advantage of people in desperate need of heart support — charging double, knowing full well their buyers had nowhere else to turn while we were in between batches.
This article is the explanation. It's the story of how a heart supplement made in Oxford ended up with a black market in the UK, why our bottles in particular became the only ones worth flipping, and why on March 2nd a man in a balaclava decided that buying ours wasn't fast enough.
It started with an industry report.
In early 2026, an independent analysis was carried out on the eight best-selling nattokinase brands in the UK. Each one was bought from its standard retail channel, sent to an ISO 17025 accredited laboratory, and tested against the dose printed on the label.
The results were, to put it mildly, unflattering for the industry.
Of the eight brands tested, seven came in below their label claim. Five came in dramatically below. Three came in at less than 30% of what they claimed to contain. The worst offender tested at 17.8% of label. One brand passed. Ours.
Verified nattokinase potency vs. label claim
Eight top-selling UK nattokinase brands tested at an ISO 17025 accredited laboratory. Potency measured in FU (Fibrinolytic Units) against the dose printed on each label. Anything under 100% means the consumer is being underdosed against the label claim.
7 of 8 brands failed. Our batch tested at 134% of label claim.
Translated out of percentages, this is what the report actually found: somebody buying the worst-performing brand on the list was getting roughly one-sixth of the nattokinase they thought they were paying for. Somebody buying the average underdosed brand was getting roughly half. Across the entire UK shelf, only one nattokinase brand was actually delivering what its label promised — and it was over-delivering, by 34%.
This is the bit that matters: nattokinase is not like a multivitamin where being slightly under the label dose is a rounding error. The clinical research on nattokinase uses specific doses — typically 2,000 FU at the very low end and 10,800 FU at the high end. Below those thresholds, the studies do not show a benefit. A bottle that delivers 17.8% of a 2,000 FU label is delivering 356 FU. That is not a heart supplement. That is a placebo with a logo on it.
Once the report circulated, three things happened, almost simultaneously.
Then the resellers arrived.
The first thing that happened was perfectly rational. People who had been buying one of the seven failed brands switched. They went looking for the only nattokinase in the UK that had passed an independent potency test. They found us.
The second thing that happened was less rational, but predictable. A small number of buyers worked out that there was now a single SKU in the entire UK heart supplement category that was both clinically dosed and demonstrably authentic, and that this SKU was selling on our site at standard retail. So they started buying it in bulk. Not in twos and threes. In dozens.
By the second week of March, our shipping team flagged the pattern. Single addresses ordering five, ten, fifteen bottles at a time. Different names. Same delivery postcodes. Some were obvious — the same packaging address re-listing the same lots on eBay 48 hours later.
This is what every reseller market looks like in its early days. A real product, in a category dominated by fakes, with retail demand outstripping retail supply. The arithmetic works out cleanly: buy at £29.99, list at £49.99 or £59.99, pocket the spread. As long as we keep being the only brand with a third-party potency certificate, the spread holds.
We are not, for the record, particularly upset about the eBay arbitrage. Every bottle is still being made by us, sold by us, and tested by us before it leaves the building. The only person worse off is the customer paying the markup — which is why, if you've landed on this page from an eBay listing, the rest of this article is for you.
Then it became a matter for the police.
The third thing that happened we genuinely did not see coming.
On March 2nd, at 14:01 GMT, a man in a balaclava walked through the storage area of our manufacturing facility in Oxford. He didn't take the cash. He didn't take the equipment. He didn't even try to be quiet. He walked directly to a bin of finished Nattokinase Arterial Support bottles, took what he could carry, and left.
It is on camera (the footage is at the top of this page). We've reported it. We're not sure yet whether he was a reseller running out of patience, or somebody planning to relabel and counterfeit, or simply somebody who had read about the potency report and decided to skip the queue. The footage doesn't say.
There is a reason this is happening now.
For most of the last decade, we sold our Nattokinase Arterial Support steadily. A few thousand bottles a month. A loyal subscriber base. Enough demand to keep two production lines busy. Easily within capacity.
Then, in 2025, two things compounded inside the same six-month window.
The first was Harry Redknapp. The former football manager began publicly recommending our heart supplement after taking it himself. Demand roughly doubled in 90 days. We adjusted production. We caught up. We kept stock on the shelf. Most of the time.
The second was the potency report. When seven of the eight largest nattokinase brands in the UK failed independent testing — and ours was the one that didn't — the entire category effectively consolidated onto our SKU overnight. People who had been loyal to other brands had nowhere else to go. People who had never tried nattokinase began with us, because the report told them to.
And third — the science. Three major published nattokinase studies landed inside the same window. The headline numbers are below.
The combined effect is what's now driving the eBay listings, the bulk-buyers, and (we have to assume) the man in the balaclava: more demand than we can comfortably supply, against a category in which we are the only brand currently testing at or above label claim.
A note about stock — and why subscribers never run out
We sold out three times in the first quarter of 2026. We've since increased our production runs and added an extra batch per month at our Oxford facility, but we still occasionally run out of certain pack sizes.
The one group of customers who never gets caught short is our subscribers. Because subscriptions give us a predictable demand curve months into the future, we can manufacture against confirmed orders rather than guessing — which means subscriber bottles are reserved from each production run before any stock is released to one-time buyers.
In plain terms: if you're on autoship, you get yours first. Always. The fastest way to make sure you never have to weigh up an eBay listing at midnight is the 90-day plan below — cancel anytime, no lock-in.
If you're going to buy ours, buy ours from us.
This article is, fairly transparently, an advertorial. We are a heart supplement company writing about a heart supplement that we make. You should weigh the source.
What you don't have to take on trust, though, is the underlying point. The lab results above are real and were generated by an ISO 17025 accredited facility. The eBay listings are real and live as of the date stamped at the top of this page. The CCTV is real. The simplest way to verify any of it is to put your own bottle through your own test — we publish every batch's certificate of analysis at testing.nfsupplements.co.uk, with the lot number printed on the side of every tub.
If, having read the article, you'd like to buy the actual product — at the actual retail price, with no markup, with the same tested batch we ship to everyone else — the order panel is below. The 90-day plan is roughly half what an eBay reseller will charge you for the same two bottles, and includes a third bottle free.
