The US pharmaceutical giant Eli Lilly sparked considerable concern among patients and healthcare providers in the UK by announcing a substantial price increase for its weight-loss drug, Mounjaro (tirzepatide), effective September 1st. Initially, Lilly planned for the wholesale price of a month's supply of the highest dose to soar from £122 to £330, with mid-range doses like the 5mg pen rising from approximately £92 to £180. The company justified this significant hike by stating it had launched Mounjaro in the UK at a price "significantly below the European average to prevent delays in NHS availability," but that this now needed to change "to ensure fair global contributions to the cost of innovation."

This announcement triggered "unprecedented demand" and "Covid-style panic buying" of the drug by patients rushing to stockpile supplies before the price change. Pharmacies across the UK reported a clear increase in Mounjaro purchases, with some patients attempting to register with multiple pharmacies to obtain the drug from various sources. In response to this surge in demand and to prevent pharmacies from stockpiling at lower prices, Eli Lilly requested a temporary UK-wide freeze on Mounjaro orders from August 27th until September 1st. UK medicines distributor Phoenix communicated this halt to pharmacies, confirming that orders received after August 27th would not be processed until September 1st.

The initial planned price increase and the temporary supply halt drew sharp criticism and raised significant concerns. Experts feared that the looming price hike could drive more people towards the black market, potentially exposing them to dangerous counterfeit medications. Robert Bradshaw, superintendent pharmacist at Oxford Online Pharmacy, warned of the risk of people receiving "fake jabs that are contaminated or contain incorrect dosages or different active ingredients," posing serious health risks. Dr. Leyla Hannbeck, CEO of the Independent Pharmacies Association, deemed Lilly's actions "completely unacceptable," stating that the company had "decided to cause significant instability by increasing prices with minimal notice" and was now "making matters worse by suspending supply." She argued that this move was "throwing the system into chaos" and that "patients are being made to suffer as a result of Eli Lilly's pursuit of profit."

However, mounting pressure led to a partial concession from Eli Lilly. Leaked documents and a subsequent statement revealed that the cost increase for Mounjaro would not be as steep as initially feared. For instance, the wholesale price of the highest dose (15mg) will now rise to £247.50, which is almost £100 less than the initially planned £330. Lower doses are also expected to receive smaller discounts compared to the initial proposals. Eli Lilly confirmed it was "working with private providers on commercial arrangements to maintain affordability" and anticipated these arrangements would be passed onto patients.

While the revised list prices offered some relief, pharmacies have begun to announce their individual charging structures, showing variability. For example, online pharmacist Curely is offering the lowest dose (2.5mg) for £136.80 and the highest dose (15mg) for £270. In contrast, Boots has indicated a price of £335 for the 15mg dose. This suggests that while the manufacturer's list price has been adjusted, actual patient costs may still vary significantly depending on the provider. The concern about the black market remains, underscored by Border Force seizures of over 18,000 illegal weight-loss and diabetes medications, including fake Mounjaro pens, at Heathrow Airport between June 2024 and June 2025.

Mounjaro is part of a growing class of weight-loss injections that have gained significant popularity. Clinical trials have demonstrated Mounjaro's impressive efficacy, with patients losing an average of up to 22.5 percent of their body weight over 72 weeks at the highest dose, outperforming alternatives like Wegovy, which shows up to 17.5 percent loss over the same period. These jabs are currently used by at least half a million NHS patients and approximately 15 million patients in the US, with even higher numbers privately. Official guidelines stipulate that these medications should primarily be prescribed to patients with a Body Mass Index (BMI) over 35 who also have at least one weight-related health problem (e.g., high blood pressure), or those with a BMI of 30-34.9 who meet criteria for referral to a specialist weight management service. The UK faces a significant obesity crisis, with nearly two-thirds of adults in England overweight and a quarter obese, costing the NHS over £11 billion annually. Patients unable to afford the new Mounjaro prices are advised to consult their prescribers or GPs about switching to alternative, safe weight-loss injections or medications, although a direct "mg-for-mg" switch between different drugs is not possible due to varying strengths.