This article has been updated as at 15 October 2025.
The Medicines and Healthcare Regulatory Agency (MHRA), the Advertising Standards Authority (ASA) and the General Pharmaceutical Council (GPhC) have joined forces to issue an Enforcement Notice to businesses offering the relatively new weight loss medicines (GLP-1 receptor agonists) reminding them that these medicines are prescription-only (POMs) and therefore cannot be advertised to the public.
The first such enforcement notice was issued by the MHRA and the ASA, and, as with this notice, arose out of concern about the advertising of these POMs generally and in social media. The new enforcement notice now includes the GPhC because pharmacies are increasingly engaging in compounding these products (manufacturing them individually per patient) in the face of supply shortages. On 23 September 2025 the joint Enforcement Notice was updated to provide clarity on the types of content that would amount to indirect advertising in breach of the advertising rules in the UK.
Why this issue and why now?
Of the medicines listed in the Enforcement Notice, some are not indicated for weight loss but rather for diabetes, while others have been repurposed for weight loss. Even those which are indicated for weight loss are indicated for a limited group of patients being those who are obese or significantly overweight and with a weight-related comorbidity. The medicines which are indicated for weight loss are not indicated for use for those who have a lower BMI and no weight-related comorbidities, but who just want to lose some weight. All the so-called 'skinny jabs' are therefore an off-label use.
The MHRA states that these medicines are "acceptably safe when used within their licensed indications". However, what is 'acceptably safe' for someone who is morbidly obese or whose excessive weight threatens their long-term health, is not necessarily true for those outside the indication. Indeed, the safety of these products in the latter population has not been studied.
These products are nevertheless being prescribed privately in ever larger numbers for people not within the group indicated in the labelling. The UK has a fairly liberal market for privately dispensed medicines. This market allows businesses to establish themselves to provide doctors giving private prescriptions and to then dispense the medicines prescribed. Other countries, such as France, require that the patient has the freedom to fill their prescription at any pharmacy of their choosing.
Businesses, including clinics and pharmacies, are competing for this business through advertising. While it is permissible to advertise weight loss services, no mention may be made of the products themselves as the Enforcement Notice reminds readers. The notice also warns advertisers to avoid indirect advertising – which is adverts that describe a product but do not mention the name. The September 2025 updates to the Enforcement Notice emphasise that adverts need not specifically refer to a medicine to amount to unlawful indirect advertising. It is prohibited to use in adverts descriptions such as 'obesity treatment jab', 'weight loss injection' and 'GLP-1', and also the use of imagery such as injection pens. The updates also warn against adverts which are seemingly for non-POMs, but which click through to a landing page that does promote a POM.
Why the concern?
This enforcement notice is a relatively rare occurrence. It is driven both by the volume of breaches to date, but also by the fact that these products are being used off-label and that they come with a list of side effects, some of which are quite commonly experienced.
As a consequence of the side-effects, the MHRA has a reminder page for healthcare professionals regarding GLP-1 receptor agonists (GLP-1 RAs) setting out the advice which should be provided to patients to whom they are being prescribed, including that:
- more than 10% of patients suffer gastrointestinal side effects which can sometimes lead to severe dehydration, resulting in hospitalisation
- there is a risk of hypoglycaemia in non-diabetic patients
- there are other serious but less common side-effects include acute gallstone disease, pancreatitis, and serious allergic reactions.
The MHRA concerns on side effects stem from the reports it has received through its Yellow Card scheme. As of 28 October 2024, the MHRA had received 7228 reports of the common gastrointestinal reactions of nausea, vomiting and diarrhoea in association with GLP-1RAs indicated for weight management (outside the licensed criteria). Of these reports, 68 reported hospitalisation of the individual. The MHRA does note though the limitations of its own reporting system.
Promotion of weight loss products can get companies into trouble
Even pharmaceutical companies such as Novo Nordisk, the manufacturer of Saxenda, have found themselves in hot water due to promotion of weight loss services. Novo Nordisk were expelled from the ABPI as a result of a breach of the Code of Practice.
Novo Nordisk sponsored training for 4399 doctors (1.5% of all licensed doctors in the UK) aspiring to work in private weight loss clinics at which the Novo Nordisk product was almost the sole focus of the product training. The resulting finding of a lack of fair balance was what led to the expulsion.
Other concerns
Another major concern for the MHRA is the number of falsified medicines on the market purporting to be GLP-1 RAs. The size of the market as well as the lack of supply has led to a sizeable online market for falsified versions of these products.
The market for private supply of medicines in the UK
The use of GLP-1 RAs off-label for weight loss purposes might be termed 'life style drugs'. They are being prescribed and supplied to meet a burgeoning demand from a population of which 64% of adults are overweight, and 26.2% are obese. The product is a weekly injection that increases in dose over time, so requires a doctor to be continuously involved to provide prescriptions.
While the benefits of these products are widely publicised in popular media in general terms, the MHRA and other regulatory bodies are concerned with adverts from 'weight loss clinics', which overstep the permissible limits and advertise directly or indirectly that they will provide these 'skinny jabs'. Their concern is further heighted by the relatively common and unpleasant side effects which can lead to hospitalisation. It is therefore important that anyone seeking these treatments are properly informed by a doctor of all the information they need to make a fully informed decision whether to use a GLP-1 inhibitor in order to lose weight, rather than through unlawful advertisements.
