Online pharmacies have been barred from promoting weight loss drugs to the public in a crackdown by the advertising watchdog.
It follows a series of controversial adverts – including one shown after Bake Off – that sparked complaints they preyed on viewers' insecurities about their weight.
UK law bans the advertising of prescription-only medicines directly to the public, as well as the promotion of drugs that have not been authorised by health regulators.
But an investigation by the Advertising Standards Authority (ASA) previously found pharmacies either breaching the rules outright or exploiting grey areas to promote weight loss jabs and pills.
Separately, pharmaceutical giant Eli Lilly has faced criticism over an advertising campaign – aired on Channel 4 in the commercial break following The Great British Bake Off last week – built around the message that 'obesity is a disease'.
Although the campaign did not name a specific drug – allowing it to comply with UK advertising rules – critics argued that it nevertheless drove interest in prescription medications.
The ASA has now issued specific new guidance governing adverts for weight loss treatments.
In the UK, advertising prescription-only medications – which includes all weight loss jabs such as Wegovy and Mounjaro – to the public is illegal
It says the move will help set clear precedents for advertisers.
'The licensing of [weight loss pills] represents a significant development in treatment options but also new challenges for regulators,' Catherine Drewett, Investigations Manager at the ASA, said.
'We've acted quickly as this market has developed and these first rulings make clear that these oral medicines, like prescription-only injections, cannot be advertised to the public.
'These are powerful medicines, so it's important that ads don't encourage people to seek treatment in ways that could put them at risk.'
Among the adverts to fall foul of the ASA in its latest rulings were those from Simple Online Pharmacy and Pharmacy Online, which promoted oral weight loss drugs through social media adverts and website content.
The watchdog found that an advert for Simple Online Pharmacy, seen on June 1 this year, promoted an unnamed oral weight loss treatment.
It invited consumers to 'join the waitlist' for the 'new oral weight loss treatment'.
Just ten days later, on June 11, the UK's first oral GLP-1 treatment for weight management – a tablet version of blockbuster jab Wegovy – was given the green light.
The ASA received several complaints pertaining to Eli Lilly's campaign
Pharmacy Online was reprimanded by the ASA over adverts promoting an unnamed weight loss pill through website pop-ups and social media after it had been licensed as a prescription-only drug.
The rulings form part of a wider crackdown on what the watchdog describes as 'irresponsible' marketing.
Three further rulings were published today against MedExpress, Juniper and the Care Pharmacy – after the ASA found consumers could identify prescription-only weight loss medicines from the overall impression created by adverts, even when the drugs were not named.
The ASA added that adverts should not feature images of weight loss injection pens or references to 'reduced appetite and cravings', even if the drug isn't named – as these could allow consumers to infer that a prescription-only medication is being promoted.
Experts say the ban on advertising prescription-only drugs protects the public from commercial pressure, helps ensure safe and regulated prescribing and prevents the medicalisation of everyday concerns that may be managed through lifestyle changes.
The ASA previously issued nine rulings in July last year, which allowed pharmacies to continue mentioning weight loss injections on their websites, provided they were not featured on homepages.
At the time, online pharmacies were also banned from using the phrase 'weight loss injections' and told the treatments must be marketed as part of a wider service, including a consultation and prescription, rather than as a stand-alone treatment.
An ASA spokesman told the Daily Mail the watchdog had received several complaints about the Eli Lilly advert that aired during Bake Off.
It confirmed the investigation had now been taken over by 'another regulator', because the complaints concerned a pharmaceutical company campaign rather than a specific medication.
The Medicines and Healthcare products Regulatory Agency (MHRA) has praised the ASA for acting swiftly against adverts that 'break the rules'.
'The MHRA expects all organisations promoting medicines to comply fully with advertising regulations, which exist to protect patient safety,' Julian Breach, the MHRA's interim executive director of healthcare, said.
'Stimulating consumer demand for a new prescription medicine is not permitted.
'We take advertising that breaches the rules when promoting prescription-only medicines to the public, including weight loss medicines, very seriously.
'Where breaches occur, we will not hesitate to use the full range of regulatory powers available to secure compliance and protect the public.'
This can include fines and court proceedings, while breaches referred to the General Pharmaceutical Council can also result in action against the pharmacy, its owner and superintendent pharmacist.
A key question, however, is whether the new rulings will curb the illegal sale and promotion of the drugs.
More than 2.5 million Britons are thought to be using weight loss drugs, the majority of whom pay privately because NHS access remains limited.
Eli Lilly declined to comment.