It was meant to be a turning point for obesity care in the UK. Instead, the rollout of the new weight loss drug tirzepatide, known commercially as Mounjaro, is exposing deep fractures in the healthcare system. Researchers from King’s College London warn that the National Health Service’s strict eligibility rules could create a two-tier system, leaving the poorest and sickest patients behind.
Published in the British Journal of General Practice, the editorial argues that the NHS plan to treat only 220,000 patients in the first three years, despite more than 1.5 million Britons already accessing GLP-1 receptor agonists privately, amounts to rationing care by income. That imbalance, they say, threatens to deepen existing health inequalities tied to socioeconomic status, ethnicity, and mental illness.
Strict Criteria, Limited Access
Under Phase 1 of the rollout, only adults with a body mass index (BMI) of 40 or above and at least four of five specific comorbidities—such as type 2 diabetes, hypertension, or cardiovascular disease—qualify for NHS-funded tirzepatide. In practice, that means many at-risk patients are excluded because they lack the formal diagnoses required to pass the eligibility gate.
The problem, researchers note, is that the very conditions used to determine eligibility are often underdiagnosed in the groups most affected by obesity. Women, ethnic minorities, and those with severe mental illness (SMI) experience disproportionately high rates of missed or delayed diagnoses. Data from the UK’s E-ECHOES study, for instance, revealed undiagnosed hypertension in more than one-third of South Asian participants and one-fifth of African-Caribbean participants.
That diagnostic gap has consequences. If a patient has not been formally diagnosed with hypertension or type 2 diabetes, they do not qualify for the medication—even if they meet all other clinical indicators.
“The planned rollout of Mounjaro risks creating a two-tier system in obesity treatment,” said Dr Laurence Dobbie, NIHR Academic Clinical Fellow in General Practice at King’s College London. “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.”
Regional disparities add another layer of inequity. As of August 2025, only eight of England’s 42 Integrated Care Boards offered tirzepatide for obesity, with some planning caps on first-year numbers. Patients in rural areas face even steeper barriers, with referral rates to weight management services five times lower than in urban centers.
Calls for a Fairer System
Lead author Dobbie and his colleagues argue that the NHS criteria should evolve to reflect real-world disparities in diagnosis and access. They propose lowering BMI thresholds over time, creating specific pathways for people with SMI, and expanding digital health programs to reduce regional inequality. They also urge policymakers to adopt guidance from the Society for Endocrinology and the Obesity Management Collaborative-UK, which recognizes conditions like cancer recovery, fertility treatment, and surgery readiness as legitimate reasons for prioritized access to GLP-1 drugs.
“Obesity is a complex, chronic disease that demands equitable access to treatment for all who need it—not just those who can afford it,” said Professor Barbara McGowan, Professor of Endocrinology and Diabetes at King’s College London. “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.”
Beyond drug eligibility, the authors emphasize that equity depends on the quality of wrap-around care. Behavioral support programs, nutritional counseling, and psychological services must be culturally tailored and sensitive to social needs such as food insecurity. Without those adjustments, even well-intentioned national programs risk reproducing the very inequities they seek to solve.
If a patient has not been formally diagnosed with hypertension or type 2 diabetes, they do not qualify for the medication, even if they meet all other clinical indicators. “We should not accept a future where the postcode or the bank balance determines who gets lifesaving treatment,” they write.
Full study available at British Journal of General Practice: 10.3399/BJGP.2025.0610
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