What Does Your BMI Need to Be for Mounjaro?

What BMI do you need to get Mounjaro on a private prescription?

The licensed eligibility criteria for Mounjaro set out in the UK Summary of Product Characteristics are clear on the numbers: a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² alongside at least one weight-related comorbidity. Those qualifying conditions include type 2 diabetes, high blood pressure (hypertension), dyslipidaemia, obstructive sleep apnoea and cardiovascular disease, among others. If you're unsure whether a condition you have counts, that question is exactly what the consultation is for.

Ethnic background matters here too. UK clinical guidance recognises that health risks tied to excess weight appear at lower BMI values in some populations. For people of South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds, the relevant thresholds are each 2.5 kg/m² lower — so 27.5 or above for the main threshold, 24.5–27.4 with a qualifying condition. A prescriber applies these adjustments as standard. You can read more about how the numbers interact with the full eligibility picture on our Mounjaro BMI guide.

One practical note: BMI is calculated from your height and weight, so the measurement needs to be accurate. At nume, weight is verified on a live video call (not self-reported) which is part of how the process keeps standards high rather than just fast.

Does the NHS use the same BMI threshold, or is it stricter?

The NHS criteria are considerably more restrictive than the licensed thresholds above. NICE's appraisal of tirzepatide (TA1026), published in December 2024, recommends Mounjaro on the NHS only for adults with a BMI of 35 or above plus at least one weight-related comorbidity, and only through a phased rollout based on how many conditions are present.

As of June 2025, NHS access requires a BMI of 40 or above with four or more qualifying conditions from a set list. From around June 2026, that opened to BMI 35–39.9 with four or more conditions. Further cohorts are expected from March 2027. These phases reflect commissioning capacity, not the science, the medicine is the same. Ethnic-background BMI adjustments of 2.5 kg/m² lower apply throughout the NHS pathway too.

For many people, the NHS criteria won't be met for years, if at all. A private prescription through a pharmacy registered on the GPhC register (like nume) uses the licensed eligibility thresholds instead, with no referral required. The treatment overview page explains how the private route works alongside NHS options.

If your BMI qualifies, is that enough to get a prescription?

Meeting the BMI threshold is a necessary condition, not a sufficient one. A prescriber looks at the full picture: your medical history, any medicines you already take, conditions that might make Mounjaro unsuitable, and your goals. There are circumstances where Mounjaro is not appropriate regardless of BMI, a history of medullary thyroid carcinoma or MEN2 syndrome, for instance, or current pregnancy. Women using oral contraceptives also need to know that for the first four weeks of Mounjaro treatment, and for four weeks after each dose increase, additional contraception such as condoms is recommended, because the pill's absorption can be affected. It's the kind of detail a thorough consultation surfaces.

The consultation at nume is reviewed personally by a GPhC-registered Independent Prescriber, a real clinician reads your answers the same day, not software. If you have questions about a specific condition, our guide on Mounjaro and high blood pressure covers one common example in detail. For a broader look at the medicine itself, the Mounjaro information page sets out how it works and what to expect.

Treatment doesn't guarantee any particular outcome. In the SURMOUNT-1 clinical trial, adults using the highest dose of tirzepatide lost around 20–21% of their body weight on average over 72 weeks, alongside a reduced-calorie diet and increased activity, but individual results vary, and no service can promise yours. What a good service can promise is that the prescription decision is made honestly and safely.

What should you do if your BMI is just below the threshold?

A BMI of 26 or 27 without any qualifying conditions falls outside the licensed criteria, and a responsible prescriber won't issue a prescription in that situation. If you're curious about what your BMI should be for Mounjaro and how different health conditions affect that calculation, it's worth reading through before you book a consultation. If your BMI sits just below 27 and you do have a relevant health condition, it's worth raising that in the consultation, the qualifying conditions list is broader than people often realise, and your GP records may document something relevant that you haven't connected to weight.

If you're genuinely below the threshold, Mounjaro isn't the right route right now, and any pharmacy suggesting otherwise should be treated with caution. Pricing questions are worth reading about too, our guide on Mounjaro pricing in the UK gives context on what legitimate private treatment costs and why large discounts on a prescription medicine are a warning sign, not a deal. For a full view of what weight management options are available at different BMI ranges, the treatments page is the right starting point. Worth checking your number carefully before booking, our page on what BMI you need to get Mounjaro walks through the specific figures alongside the NHS BMI tool, which takes about a minute and gives you a reliable figure to work from.

Keep the pen in the fridge door and the dosing diary on your phone, treatment, once started and clinically appropriate, becomes straightforward routine. Getting the eligibility assessment right first is what makes that possible. Speak to our prescribers if you want a same-day clinical review of your situation.