The NHS is preparing to begin a phased rollout of the weight-loss medication Mounjaro across England, Wales, and Northern Ireland next week, marking a significant expansion in access to the drug beyond specialist weight-management clinics. The treatment, which is also used for type 2 diabetes, will gradually become available through selected GP services, although strict eligibility rules mean only a limited number of patients will qualify. To be considered, individuals must typically have a body mass index (BMI) between 35 and 39.9, along with at least four serious health conditions such as type 2 diabetes, hypertension, heart disease, or sleep apnoea. Health officials have emphasized that demand is expected to far exceed supply, with only around 220,000 people set to be offered the medication over the next three years under the current rollout plan.

Mounjaro works by mimicking two hormones involved in appetite and blood sugar regulation, helping patients feel fuller for longer while also improving insulin response. Because of this mechanism, it is often compared to other weight-loss injections such as semaglutide-based treatments, though Mounjaro is considered a dual-action therapy. Despite its benefits, healthcare professionals have highlighted a range of potential side effects that patients should be aware of before starting treatment. According to Diabetes UK, these include nausea, indigestion, constipation, diarrhoea, and the risk of both low and high blood sugar levels. General practitioners have also warned that they will not be able to prescribe the drug to everyone who requests it, stressing that it will only be offered to patients with the greatest medical need. Some surgeries have already stated they will not accept direct requests, reflecting concerns about workload pressures and high public demand.