What weight do you have to be to get Mounjaro?

Step 1: find your BMI and see which threshold applies to you

BMI (body mass index) is the starting point for Mounjaro eligibility, both in the licensed criteria and in clinical practice. The figures come from Mounjaro's UK licence: adults with a BMI of 30 or above qualify on BMI alone. Adults with a BMI between 27 and 29.9 qualify only if they also have at least one condition that is worsened by excess weight. The conditions that count in this context include type 2 diabetes, high blood pressure, raised cholesterol, obstructive sleep apnoea and cardiovascular disease, though prescribers look at the clinical picture in the round rather than ticking a single box.

The NHS BMI calculator is a quick way to check your own figure, it asks for your height and weight and gives you a reading in under a minute. One important nuance: for people of South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds, UK guidance reduces the BMI threshold by 2.5 kg/m², because excess weight tends to carry greater health risks at lower BMIs in these groups. So if your heritage puts you in one of those categories, a BMI of 27.5 rather than 30 may be the starting point for eligibility without a comorbidity.

If you're unsure where you stand, the weight requirements for Mounjaro explained in full go into more detail on the numbers by condition.

Step 2: understand the difference between NHS and private eligibility

The BMI numbers above describe Mounjaro's licence, what it's approved to treat. NHS access is considerably narrower. NICE's appraisal of tirzepatide (TA1026) recommends it on the NHS only for adults with a BMI of 35 or above and at least one weight-related comorbidity, and only through NHS specialist weight management services as the rollout phases in. The NHS rollout is happening in stages: from June 2025, priority went to people with a BMI of 40 or above and four or more of five qualifying conditions; from around June 2026, that widened to include a BMI of 35–39.9. Waiting lists are real, and not everyone who meets the criteria gets prompt access. See how NHS and private eligibility compare if you'd like the two routes side by side.

Private treatment through a GPhC-registered pharmacy follows the licensed criteria instead, the broader BMI 30/27-with-condition thresholds. That's why many people who don't meet the NHS threshold, or who don't want to wait, choose a regulated private route. For context on what private treatment costs, Mounjaro pricing in the UK sets out what to expect and what a legitimate price should include.

Step 3: know what else a prescriber looks at beyond the number on the scales

BMI opens the door; it doesn't guarantee a prescription. A GPhC-registered Independent Prescriber reviews your consultation in full, your medical history, any current medicines, and conditions that could affect whether Mounjaro is safe for you specifically. Mounjaro is not licensed for use during pregnancy, when trying to conceive, or while breastfeeding. It isn't suitable for people under 18. A personal or family history of medullary thyroid carcinoma or MEN2 syndrome, or a history of pancreatitis, means the prescriber needs to assess risk carefully before prescribing.

Medicines you're already taking matter too. Women using oral contraceptives, for instance, are advised to add a non-oral method of contraception for the first four weeks of Mounjaro treatment and for four weeks after each dose increase, because the pill's absorption can be affected. That's the kind of thing a prescriber flags in consultation, it's one reason a proper clinical review is part of the process, not an optional extra. Our clinical team at nume reviews every consultation personally.

Age is its own consideration. The age requirements for Mounjaro explain why it isn't currently licensed below 18 and what that means for consultation.

A note on timing your consultation

A question our prescribers hear fairly often: does it matter when in the month you start? Not clinically, no. Practically, some people time their first order around payday or the start of a new week, there's nothing wrong with that, and ordering by 12pm Monday to Friday means a same-day dispatch once approved. Just check the pharmacy is on the GPhC register before you share any health information with them; you can verify any registered pharmacy at the GPhC register. For a fuller picture of how tirzepatide works and what the clinical trial evidence shows, the tirzepatide overview is a good next read, and NICE's full appraisal of tirzepatide (TA1026) sets out the evidence the NHS used to recommend it. If you have questions about eligibility that aren't covered here, our FAQs cover the most common ones.

When you're ready to see whether you're likely to be eligible, check your eligibility with a free consultation, a prescriber reviews every submission personally, the same day.