The NHS criteria for weight loss injections, explained clearly

You've checked the BMI number, but there's a checklist too

Imagine you've just run your BMI through the NHS calculator and it sits at 41. You've read somewhere that NHS weight loss injections are now available and you're wondering whether to bring it up at your next GP appointment. That's a reasonable starting point, but BMI alone isn't the full picture.

For tirzepatide (branded Mounjaro, the dual GIP and GLP-1 receptor agonist that NICE recommended in December 2024) NHS eligibility currently requires a BMI of 40 or above and four or more of five specific health conditions: high blood pressure, dyslipidaemia (raised cholesterol or triglycerides), obstructive sleep apnoea, cardiovascular disease, and type 2 diabetes. That's a tight combination. Many people with a BMI over 40 will have one or two of those conditions, but not four. Understanding the BMI rules for NHS weight loss injections can help you work out where you stand before speaking to your GP.

The ethnic-background adjustment matters here too. For South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds, UK guidance sets the BMI thresholds 2.5 kg/m² lower throughout, so 37.5 instead of 40 for Cohort 1, and 32.5 instead of 35 for Cohort 2. NICE confirmed this in its appraisal of tirzepatide (TA1026), and it applies to NHS access.

Worth checking: criteria set the floor, not a guarantee. Your GP practice also needs to be actively participating in the commissioning arrangement, and places in the wrap-around lifestyle programme are finite.

The phased rollout, which cohort are you in?

NHS England is adding eligible groups in stages, rather than opening access to everyone at once. The approach was set out following the NICE recommendation for tirzepatide, and it reflects both clinical prioritisation and the supply realities of rolling out a new treatment at scale.

Cohort 1 opened in June 2025: adults with a BMI of 40 or above and four or more of the five qualifying conditions. Cohort 2 followed on 23 June 2026: the same four-condition requirement, but the BMI floor drops to 35–39.9. A further cohort, covering BMI 40 or above with three or more conditions, is expected around March 2027. The full NHS weight loss injections rollout timeline has more detail on what's coming and when.

For Wegovy (semaglutide, a GLP-1 injection), NHS access follows a different path. NICE recommended it in 2023 under TA875, but only through specialist weight management services, for a maximum of two years, and with a BMI of 35 or above alongside at least one weight-related condition. Waiting lists for specialist services tend to be long in most areas.

Scotland, Wales and Northern Ireland each have their own thresholds and access routes. If you're in Scotland, the NHS Scotland criteria for weight loss injections differ in important ways and are worth reading separately.

What happens once you meet the criteria

Meeting the criteria on paper is step one. From 1 April 2026, GP practices in England can prescribe tirzepatide directly under a new GP contract arrangement, but participation is optional, and not every practice has signed up. Some areas are further ahead than others. If your practice isn't yet involved, you may be referred to a specialist service instead, or you may need to wait.

Every NHS patient on a weight loss injection must also engage with wrap-around support, structured diet and activity guidance, alongside the medicine. This isn't bureaucratic box-ticking; the clinical trials that underpinned NICE's recommendation were all conducted in the context of lifestyle changes, and NHS England's guidance on weight management injections makes this a condition of treatment. You'll typically have regular check-ins, and if you haven't lost at least 5% of body weight after six months at the highest tolerated dose, continuing treatment is reviewed.

If cost is a consideration alongside access, a straightforward guide to what weight loss injections cost in the UK sets out the private market context clearly.

If you don't meet the NHS criteria right now

This is where a lot of people find themselves. Perhaps your BMI is 36 and you have two qualifying conditions rather than four. Perhaps your GP practice isn't yet participating. Perhaps you're in a part of the country where specialist waiting lists stretch into next year and you'd rather not wait.

Private prescribing through a regulated online pharmacy is the alternative. The licensed eligibility for Mounjaro and Wegovy in the private setting follows the medicine's SmPC rather than NHS commissioning rules: broadly, a BMI of 30 or above, or 27 or above with at least one weight-related condition. That's a meaningfully wider group than the current NHS cohorts. If you're considering this route, a practical guide to buying weight loss injections privately covers what to look for and how the process works. A real prescriber reviews your consultation before any treatment is issued, a plain overview of how weight loss injections work in the UK covers both routes if you want to compare them.

It's sensible to verify any online pharmacy you consider: check the GPhC register at pharmacyregulation.org before placing any order. These are prescription-only medicines, and the clinical assessment step exists for good reason, wherever you access treatment.

If you'd like a prescriber to review your individual situation, you're welcome to start a free consultation with the team at nume. There's no obligation, and eligibility is assessed by a GPhC-registered prescriber reading your answers personally.