How demand for a new weight-loss drug is fueling a counterfeit market

Retatrutide has not been approved for human use anywhere, but products claiming to be the experimental weight-loss drug are already widely available in Britain. They are being sold through gyms, nail and beauty salons, hairdressers, social media and even by flower sellers on the street.

Experts told the BBC that they rarely see copycat versions of a drug become so widely available while it remains in clinical trials. Users call it “reta” and share before-and-after images on TikTok, saying it has quieted their cravings, helped them lose weight and transformed their lives.

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The world has gone mad.

The appeal comes despite the uncertainty surrounding the real drug. Retatrutide has shown positive results in recent clinical trials, but researchers are still testing its safety and effectiveness. Only half of drugs that reach Phase III trials in the United States eventually receive Food and Drug Administration approval. Some fail because they perform less well in larger and more diverse groups, while others reveal unexpected safety risks.

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People are effectively injecting an illegal drug and thinking it's safe.

Eli Lilly, which is developing retatrutide, warns that nobody should take anything claiming to be the drug outside a company-sponsored clinical trial. It says illicit products may contain unknown ingredients, contaminants or impurities, and may have too much, too little or none of the correct active ingredient.

Pharmacist Sehar Shahid said people were “effectively injecting an illegal drug and thinking it's safe.” Endocrinologist Prof Donal O'Shea said young, fit patients had arrived at hospitals with nausea, vomiting and diarrhoea, and in some cases kidney failure. Some personal trainers, he said, were supplying and injecting the products without patients knowing what they had received or how much they had taken.

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No one should take anything claiming to be retatrutide outside of a Lilly-sponsored clinical trial.