More than 2,000 counterfeit weight loss jabs have been confiscated from a factory in Northampton, in what's believed to be the world's largest seizure.
The UK's medicines regulator and police joined forces to smash the illicit facility, which was manufacturing and distributing unlicensed products.
Labels suggested the knock-off pens contained tirzepatide, an ingredient found in Mounjaro.
But Eli Lilly, the company behind the real medication, said anyone who bought these jabs on the black market would have "no way of knowing what they actually contain".
This is the first seizure of its kind in the UK - with raw chemicals, equipment, tens of thousands of empty pens and £20,000 in cash also recovered from the site.
Estimates suggest that the street value of the counterfeit jabs is about £250,000.
Health Secretary Wes Streeting said: "This is a victory in the fight against the shameless criminals who are putting lives at risk by peddling dangerous and illegal weight loss jabs to make a quick buck.
"These unregulated products, made with no regard for safety or quality, posed a major risk to unwitting consumers."
Mr Streeting urged the public not to buy weight loss medication from unregulated sources - as this "lines the pockets of criminals who don't care about your health".
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Andy Morling, the head of the Medicines and Healthcare products Regulatory Agency's (MHRA) criminal enforcement unit, described the seizure as a "landmark result and a major blow to the illegal trade".
He added: "These products are untested, unauthorised and potentially deadly. By taking this organised criminal network out of operation - and stopping tens of thousands of products from entering circulation - we've prevented a serious risk to public health."
According to Pharmacy magazine, no arrests have been made in connection with the seizure so far.
At the moment, weight loss jabs are only available on the NHS to patients who meet strict criteria.
Private prescriptions are available but can cost hundreds of pounds a month.
(c) Sky News 2025: UK makes world's biggest-ever seizure of fake weight loss jabs
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