The MHRA continues to warn about the serious risks linked to buying weight-loss products from unregulated websites or through social media. Products sold illegally may be fake, contaminated, incorrectly dosed, or contain powerful ingredients not listed on the packaging. These can lead to dangerous side effects, including heart problems, psychological effects and dangerously low blood sugar.

Health minister, Dr Zubir Ahmed, said: ‘As a practising doctor and patient safety minister, I want to be absolutely clear - please do not buy weight loss medications from unregulated sources.

‘These products are made with no regard for safety or quality and pose a major risk to unwitting customers. Don't line the pockets of criminals who don't care about your health.'

Jenn Matthissen, from the MHRA's safety and surveillance team, added: ‘People often look for ways to support their health at this time of year, but buying medicines from illegal online sellers can put your health at real risk. Always make sure you are using authorised products from legitimate sources and speak to a healthcare professional for advice on safe, evidence-based options.'

Pharmacies are also urging patients to avoid buying weight loss injections from unregulated suppliers as the National Pharmacy Association (NPA) predicts demand to surge in the new year.

The warning comes as new polling by YouGov, commissioned by the NPA suggests that 6% of adults are likely to use weight loss injections in the new year. This is equivalent to 3.3 million people, NPA analysis suggests. That would be two and half times higher than the estimated 1.5 million people using the jabs monthly in 2025.

The polling data suggests that 9% of 25–49-year-olds are likely to take weight-loss jabs in the next year.

There have been reports that unregulated sellers have become more sophisticated in recent months to lure patients, setting up websites that look very similar to legitimate regulated online pharmacies or online doctors.

Olivier Picard, chair of the National Pharmacy Association, said: ‘With these scams becoming more sophisticated, it is really important that patients wanting to explore starting weight management treatment only go to regulated pharmacies, either online or in person on your high street.'