WeightWatchers (WW International Inc) once a dominant force in the diet industry, filed for bankruptcy in May 2025. This marks a pivotal moment in the evolution of weight loss strategies, as pharmaceutical interventions like Ozempic and Mounjaro reshape consumer behaviour. How does this change the legal landscape?
The Rise of Pharmaceutical Weight Loss
Ozempic (semaglutide), developed by Novo Nordisk, and Mounjaro (tirzepatide), manufactured by Eli Lilly, were originally designed to treat type 2 diabetes. These drugs initially rose to fame in the US as the product of pharmaceutical giant Novo Nordisk. It is a GLP-1 receptor agonist used to lower blood sugar and promote weight loss. There has been to a surge in demand with many celebrities confirming that they have used these products, shifting consumer preferences away from traditional diet programmes such as WeightWatchers.
Meanwhile, Mounjaro has entered the UK market as part of clinical trials between the UK Government and UK manufacturer Eli Lilly. It is a newer medication that acts on both GLP-1 and GIP receptors, offering even greater metabolic effects.
While both drugs mimic gut hormones that regulate appetite, blood sugar and digestion, which has made them effective, they are not without risk.
Despite their popularity, these drugs have found themselves at the centre of US lawsuits. The majority of these lawsuits stem from the claim that manufacturers failed to adequately warn patients and healthcare providers of the risks. As of November 2025, around 2,809 of these are active lawsuits against Monujaro and other GLP-1 drugs.
What are the risks?
In some cases, customers have suffered, gastroparesis (paralysed stomach), pancreatitis, gallbladder disease, blood clots, vision loss, kidney complications and severe gastrointestinal symptoms such as chronic diarrhoea or constipation. New findings have also suggested that these pharmaceutical drugs can increase suicidal thoughts and make oral contraceptives less effective.
It is clear that while Ozempic and Mounjaro may present an accessible alternative to more traditional weight loss avenues, the side effects can have lasting impacts on daily life. Some claimants have reportedly been hospitalised, requiring surgery or suffering lasting physical and emotional distress.
Investigations undertaken by the BBC ‘‘found [that] online sellers [were] offering semaglutide as medicine, without a prescription.’’ This has created an inherent risk due to the lack of regulation and or training, enabling sellers to prescribe something without correctly advising patients.
The Legal Grounds for a Claim?
Although, the majority of legal claims involving these drugs have been in the US, it is important to understand how claims may evolve in the UK. These claims typically fall under the category of product liability and the alleged:
- failure to warn customers about side effects;
- negligence in drug testing or marketing;
- defective design or manufacturing flaws; and or
- misrepresentation in advertising and public communications.
In some cases, medical negligence claims may also be considered when prescribers have failed to properly inform patients of risks or monitor them adequately.
Where does this leave traditional diet programmes?
In response to the changing market, WeightWatchers acquired the telehealth platform Sequence in 2023 for $106 million, aiming to integrate prescription weight-loss medications into its offerings. The company also introduced compounded semaglutide to enhance accessibility and affordability for its members.
Despite these efforts, WeightWatchers faced challenges in fully adapting to the new paradigm. The company's traditional points-based system and emphasis on behavioural change struggled to compete with the allure of pharmaceutical solutions promising rapid results. Subscriber numbers declined, and revenue dropped from over $1.5 billion in 2018 to under $800 million by 2024.
The combination of declining membership, increased competition from Ozempic and Mounjaro, and a substantial debt burden of $1.6 billion led WeightWatchers to file for bankruptcy protection in May 2025. The company will undergo a comprehensive financial reorganisation implemented through a prepackaged chapter 11 plan for recognition following the execution of a restructuring support agreement. This agreement will transfer control to secured lenders and bondholders, with shareholders potentially retaining up to 10% equity. This plan was expected to consummate in the second quarter of 2025, enabling WeightWatchers to continue to operate. Since then, we have seen WeightWatchers emerge with a new brand identity.
WeightWatchers' bankruptcy highlights a broader shift in the weight loss industry towards medicalised solutions. As Ozempic and Mounjaro become more prevalent, traditional diet programs must adapt to survive. The company's experience serves as a cautionary tale for other wellness brands navigating this new landscape.
While WeightWatchers aims to emerge from bankruptcy with a renewed focus on integrating pharmaceutical and behavioural approaches, the path forward remains uncertain. It is clear that while there are benefits to Ozempic and Mounjaro, there are equally inherent risks, will these risks open the door for WeightWatchers and the alike to fight on.
If you have been affected as a result of using these products, please get in touch with a member of Thorntons Personal Injury team for specialist legal guidance.
