More patients to qualify for weight-loss jab as NHS lowers BMI threshold

More people in England will become eligible for the weight-loss injection Mounjaro from late June, as the NHS moves into the next phase of its phased rollout of the drug in primary care. The change marks one of the most significant expansions yet in how the health service makes treatments for obesity available to the general population, and it is expected to draw fresh attention to a programme that has already prompted intense public interest.

Under NHS England's interim commissioning guidance, the body mass index (BMI) threshold for prescribing in general practice is set to drop from 40 to 35, provided patients also have a number of qualifying weight-related health conditions. In practical terms, that opens the door to a larger group of people who are living with obesity alongside problems such as type 2 diabetes, high blood pressure, cardiovascular disease or obstructive sleep apnoea.

The move reflects a deliberate strategy of widening access gradually rather than all at once. Officials have repeatedly stressed that the medication is not intended as a quick fix or a lifestyle product, but as a clinical intervention for those whose health is most at risk, and who are likely to gain the greatest benefit from treatment over time.

A phased approach

Mounjaro, also known by its active ingredient tirzepatide, became the first weight-loss injection that GPs could prescribe directly when the rollout began in 2025. The programme is being expanded gradually over several years, with access prioritised for those expected to benefit most. The phased model was designed to balance growing demand against the practical limits of a primary care system already under considerable strain.

Prescribing remains targeted at prioritised patient cohorts set out by NHS England rather than being available to everyone, and individual practices are not required to take part, meaning availability may vary by area. This patchwork of provision has raised concerns about a possible postcode lottery, with some patients able to access treatment through their local surgery while others in neighbouring areas may need to look elsewhere.

The drug works by mimicking hormones that regulate appetite and blood sugar, helping people feel fuller for longer and reducing how much they eat. Clinical trials have shown substantial average weight loss when the medication is combined with diet and physical activity, which is why the NHS pairs prescriptions with wider lifestyle support rather than offering the jab in isolation.

Pressure on services

Pharmacy and GP bodies have cautioned that demand could outstrip capacity, given the monitoring required in the early stages of treatment. Patients beginning the medication need careful follow-up to manage side effects, adjust doses and ensure the treatment is working as intended, all of which places additional demands on practices that are already stretched.

Representatives of general practice have warned that without extra resourcing, the expansion risks adding to existing workloads rather than easing the long-term burden of obesity-related illness. There have also been calls for clearer national guidance on how patients should be supported if they stop taking the drug, given that weight regain is common once treatment ends.

• The BMI threshold for GP prescribing falls from 40 to 35 for eligible patients
• Patients must also have qualifying weight-related health conditions
• Practices can choose whether to take part, so access may vary locally
• Treatment is paired with diet and lifestyle support, not offered alone
• Early-stage monitoring adds to demands on primary care

“The clinical case for treating obesity earlier is strong, but expansion only works if practices have the time and support to monitor patients safely.”

— A primary care representative

Background and context

Obesity has become one of the most pressing public health challenges in the UK, linked to a wide range of conditions including type 2 diabetes, heart disease, joint problems and several forms of cancer. The associated costs to the health service and the wider economy run to billions of pounds each year, and successive governments have searched for effective ways to reverse the trend.

The arrival of a new generation of weight-loss medicines has been described by some clinicians as a turning point, offering a pharmaceutical option for a problem that has long resisted advice on diet and exercise alone. At the same time, experts caution that medication is not a substitute for broader efforts to improve diets, increase physical activity and address the social factors that drive obesity in the first place.

What happens next

From late June, GPs in participating practices will begin assessing patients against the new criteria, and the number of people starting treatment is expected to rise. NHS England has signalled that further phases of the rollout will follow in the coming years, gradually widening eligibility as capacity allows. For now, much will depend on how individual areas manage demand, and whether the additional monitoring required can be delivered without overwhelming services. The expansion is a clear statement of intent on tackling obesity, but its success will be measured not at the moment of announcement, but in the health outcomes recorded over the years ahead.