Specialists from King's College London and the Obesity Management Collaborative (OMC-UK) say current eligibility rules mean only a limited number of patients can receive the weight loss drug Mounjaro through the NHS. As a result, many people who want the treatment are paying out of pocket instead.

In an editorial published in the British Journal of General Practice (BJGP), the researchers argue that this gap in access risks creating a system where financial means play a major role in who receives care.

Rising Demand for New Obesity Drugs

Obesity is a worldwide public health crisis linked to serious illnesses, including heart disease, type 2 diabetes, and cancer. The NHS rollout of tirzepatide, also known as Mounjaro, has been welcomed as an important step toward addressing these risks.

However, recent figures suggest that more than one and a half million people in the UK are already accessing these newer weight loss medications through private providers. By comparison, NHS access is expected to reach only about 200,000 patients over the first three years of the program.

Strict Eligibility Limits NHS Access

Under current NHS guidelines, patients must have a body mass index of 40 or higher and also have multiple related health conditions, such as diabetes, high blood pressure, or heart disease, to qualify for Mounjaro. While this approach offers treatment to some people with severe obesity, it excludes many others who face significant health risks but do not meet every requirement.

Researchers caution that these rules could deepen existing health inequalities by preventing high-risk individuals from receiving timely care.

Experts Warn of Widening Health Inequality

Lead author Dr. Laurence Dobbie, an NIHR Academic Clinical Fellow in General Practice at King's College London, said the current approach could unintentionally make obesity care less fair.

"The planned rollout of Mounjaro risks creating a two-tier system in obesity treatment. Unless we adjust how eligibility is defined and how services are delivered, the planned roll-out of Mounjaro risks worsening health inequalities, where ability to self-fund determines access to treatment and those with the greatest need are less likely to qualify for treatment.

"Current eligibility criteria require multiple diagnosed qualifying criteria, yet the very conditions used to gatekeep access to Mounjaro are frequently under-diagnosed in women, people from minority ethnic communities, those from low income and patients with severe mental illness. The under-diagnosis is well-documented and regional variation in NHS commissioning creates a postcode lottery.

"We should recognize under-diagnosis explicitly in obesity pathways, prioritize our patients at the highest clinical need, and scale culturally adapted wrap-around support so access is based on need, not means or location."

Professor Barbara McGowan, Professor in Endocrinology and Diabetes at King's College London, emphasized that obesity should be treated as a long-term medical condition requiring fair access to care.

"Obesity is a complex, chronic disease that demands equitable access to treatment for all who need it -- not just those who can afford it. The current approach risks entrenching a two-tier system where wealth, rather than medical need, determines access to care. We urgently need a more inclusive, fair and scalable model that ensures effective treatments are accessible across all communities, especially those already facing systemic barriers to healthcare."

Professor Mariam Molokhia, Professor in Epidemiology and Primary Care at King's College London, added that where someone lives or how much they earn should not decide whether they receive obesity care.

"Obesity care should not depend on postcode or the ability to self-fund. Current criteria risk excluding high-need patients because qualifying conditions are often under-diagnosed in the very groups who face the greatest barriers to care. For equitable delivery of care it is important to: recognize under-diagnosis in eligibility criteria, prioritize severe obesity and those with the highest clinical needs, and provide culturally adapted behavioral support."

Calls for Policy Changes and Broader Support

The authors of the opinion piece urge policymakers to make changes aimed at improving fairness and access. Their recommendations include revising eligibility criteria, creating clearer pathways to care that account for ethnicity and under-diagnosis, speeding up the national rollout, and expanding digital health services in areas with limited specialist support.

They also stress that medication alone is not enough. Effective obesity care, they argue, must be combined with broader public health efforts, such as improving diet quality, reducing food insecurity, and creating healthier urban environments.

Without prompt policy changes, the researchers warn that inequalities in obesity treatment are likely to continue and may become even more pronounced for future generations.