What's the criteria for weight loss injections in the UK?

What the published evidence and licences say about who qualifies

NICE and the medicines' regulators have been clear about the population these treatments are designed for. Tirzepatide's UK licence covers adults managing their weight alongside a reduced-calorie diet and increased physical activity, where BMI is 30 or above, or 27 or above alongside at least one weight-related condition such as hypertension, dyslipidaemia, obstructive sleep apnoea, type 2 diabetes or cardiovascular disease. NICE's appraisal of tirzepatide, TA1026, added a slightly higher BMI bar for NHS use (35 or above, with at least one comorbidity) while confirming that the 2.5 kg/m² ethnic-background adjustment applies throughout. Semaglutide (Wegovy) carries comparable licensed criteria and has its own NICE appraisal (TA875).

The trial populations matter here too. SURMOUNT-1, the landmark tirzepatide study, enrolled adults with obesity or overweight plus at least one weight-related condition, precisely the group these criteria are designed to identify. Across roughly 2,500 participants, average weight loss at the highest dose reached around 20–21% over 72 weeks. That evidence base is part of why regulators drew the eligibility lines where they did. Understanding the full eligibility criteria for weight loss injections helps set realistic expectations before you book a consultation.

NHS versus private: why the thresholds feel so different

This is a question our prescribers hear most weeks, and the confusion is understandable. The NHS and a private prescription do not use identical criteria, even for the same medicine.

On the NHS, access to tirzepatide is being rolled out in phases. From June 2025, the first cohort required a BMI of 40 or above plus four or more of five specified conditions. A second cohort, with a BMI of 35–39.9 and four or more conditions, was activated in June 2026. Further cohorts will open from around March 2027. Even when you meet those criteria, your GP practice must be participating in the relevant commissioning arrangement, and wrap-around lifestyle support is a condition of treatment. Wegovy on the NHS is routed through specialist weight management services, with waiting lists that can stretch for months or years in some areas.

Private prescribing follows the medicine's licensed criteria more directly: BMI 30 or above, or 27 with a qualifying condition. That wider net is why many people who are clinically eligible for these medicines cannot yet access them on the NHS. Exploring your treatment options privately does not mean bypassing clinical safeguards, it means the same prescriber-led assessment, applied to the licensed population the medicine was tested in.

What a prescriber actually looks at beyond your BMI

A BMI above the threshold gets your foot in the door. It does not open it automatically. Prescribers review contraindications and cautions alongside the numbers: a personal or family history of medullary thyroid cancer or a condition called MEN2, a history of pancreatitis, and certain gastrointestinal conditions all require careful discussion or rule treatment out. Current medicines matter too, some interact with GLP-1 medicines in ways that need managing, and for women using the oral contraceptive pill, additional contraception is advised during the early weeks of tirzepatide treatment because absorption of the pill may be reduced, as NHS England's guidance on weight management injections sets out.

Pregnancy, breastfeeding and planning a pregnancy are not compatible with these treatments; under-18s are outside the licensed population for both medicines. A prescriber also looks at whether you have previously tried a GLP-1 medicine, what dose you reached, and whether your health records support continuing or increasing treatment. None of that is bureaucracy for its own sake. It is the clinical structure that makes safety a genuine feature of supervised treatment, not just a label on a box. You can read about our clinical team's approach on the clinical team page.

If you meet the criteria, what happens next

Knowing you likely qualify is useful; confirming it with a prescriber is the step that counts. At nume, the process starts with a free consultation, questions about your health, your weight history and your goals, reviewed the same day by a GPhC-registered prescriber, not a piece of software. Identity is verified, and weight is confirmed on video so there is no ambiguity. If the prescriber decides treatment is clinically appropriate, your medicine is dispatched and arrives free the next working day in plain packaging.

If you are weighing up which injection might suit you better, the comparison between licensed options is worth reading before your consultation. Cost is a real consideration too, and you can find a plain-language breakdown on what weight loss injections cost in the UK. The new injections that have entered the market recently are covered in this guide to the latest licensed options.

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