Weight loss injections: Key lessons for food advertisers

We are at that time of year when traditionally the focus switches from indulgence to abstinence.

And although the restrictions on advertising “less healthy food” might mean that the change isn't as stark as previous years, January still means new year's resolutions and inevitably, weight loss ads. It's not just classic gym memberships, slimming clubs and healthy choices that are on offer, the increased use of prescription weight-loss injections has seen an increase in advertising for food products especially supplements referencing weight-loss medication.

Advertisers of foods, drinks and food supplements need to be aware that referencing conditions that are considered medicinal or medical in law is likely to amount to advertising a medicine without a licence. Add to this the fact that advertising for food cannot include claims that state or imply a food prevents, treats or cures human disease and claims that a product has a beneficial impact on health can only be made if authorised, and it's a recipe for trouble for food advertisers seeking to talk about their products in the context of weight loss injections.

POM ad prohibitions

Prescription only medicines (POM) cannot be advertised to the public and claims to have a medicinal effect on the body can only be made with a marketing authorisation.

Readers of our 'ASA insights' will know this is an area where the Advertising Standards Authority (ASA) has been taking action, sometimes fuelled by complaints but more often by its Active Ad Monitoring system, which is set up to find potentially non-compliant ads for the ASA to assess. Last year a number of clinics tripped up and were found in breach of the Ad Codes because their advertising promoted a POM to the public.

Marketing authorisations and authorised health claims

The key point to remember is that the concept of a medical condition or disease for these purposes is much broader than one would generally think of it, so referencing obesity when talking about food products is likely to amount to making a claim to treat a disease/medicinal claim for a food. Referencing medicines and making comparisons to medicines is likely to be taken as an implied claim that the food supplement has medicinal properties without the necessary authorisation. Claims that food supplements were "like GLP-1 drugs just natural" and which made efficacy claims in comparison with POMs were ruled non-compliant in 2025.

Claims which refer to weight-loss or related factors such as digestion or metabolism need to be listed as authorised on the Great Britain nutrition and health claims Register (NHC Register). General claims need to be accompanied by specific authorised claims. Previously claims such as “trim the waist while sleeping” and “burn more fat” have been ruled non-compliant by the ASA because no such claims appear on the NHC Register. The ASA has also ruled against ads for food supplements which claimed “supercharge your metabolism” and “supports blood sugar balance” in the context of weight-loss injections for this reason. 

Food advertisements may not include health claims which refer to the recommendation of an individual health professional and are barred from making claims about a rate or amount of weight loss (e.g. “Lose 15-20% of body weight”).

While the ASA enforces the Advertising Codes which don't apply to on-pack claims (unless the packaging appears in an ad), the Codes reflect medicines and food law which also applies to claims on packaging.