What weight do you need to be for Mounjaro in the UK?

Why the answer is BMI, not a number on the scales

The most common misconception here is that there is a specific weight in kilograms or stones that 'qualifies' you for Mounjaro. There isn't. The licensed criterion is body mass index, which accounts for height alongside weight. Two people at identical weights can sit on opposite sides of the eligibility line simply because of how tall they are. If you want a fuller picture before anything else, our guide to what weight you need to be for Mounjaro explains how BMI and height interact in practice. Once you know that, the rest of the criteria become straightforward to follow.

For private prescribing in the UK, the medicine's licence sets the floor: BMI 30 or higher, or BMI between 27 and 29.9 where at least one relevant health condition is present. That condition list covers things most people don't realise count, prediabetes, hypertension, raised cholesterol, obstructive sleep apnoea and osteoarthritis are all included alongside type 2 diabetes. If you're unsure whether something on your medical history qualifies, the prescriber is the right person to ask. Our detailed breakdown of the weight and BMI thresholds steps through each criterion if you want more context before a consultation.

You can check your current BMI against these criteria using the NHS BMI calculator, it takes about 30 seconds and gives you a starting point, though the prescriber's assessment is what counts.

NHS criteria versus private licensed eligibility, not the same thing

There is a meaningful gap between what NHS England will fund and what the Mounjaro licence permits for private prescribing, and it trips people up regularly.

NICE's technology appraisal TA1026, published in December 2024, recommends tirzepatide within the NHS for adults with BMI ≥35 alongside at least one of a defined list of weight-related conditions. The rollout is phased: from June 2025, NHS prescribing began for those with BMI ≥40 and four or more qualifying conditions; Cohort 2 (BMI 35–39.9 with four or more conditions) was activated in June 2026. Further NHS cohorts are planned into 2027. That is a deliberately narrow starting point to manage NHS capacity.

Private prescribing follows the medicine's full UK licence. That means BMI ≥30 without requiring any comorbidity, or BMI ≥27 with one qualifying condition. No waiting list, no phased rollout. The prescriber still needs to be satisfied about your health picture (contraindications, current medicines and medical history all factor in) but the BMI threshold is considerably lower. Our page on the minimum BMI for Mounjaro goes further on where exactly that lower boundary sits and what conditions count.

Scotland, Wales and Northern Ireland operate their own access frameworks, so NHS eligibility there differs from NHS England's phased approach.

What the prescriber is actually weighing up beyond BMI

Reaching the BMI threshold is the entry point, not the finish line. A prescriber reviewing a consultation looks at several other factors before approving treatment.

Contraindications matter. A history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2 rules Mounjaro out. Active pancreatitis or a history of significant pancreatic disease requires careful discussion. Certain kidney or gastrointestinal conditions, and combinations of medicines, also affect suitability. Women planning to conceive should be aware that tirzepatide is not recommended during pregnancy or when trying for a baby; reliable contraception is important during treatment, and those using oral contraceptives should add a barrier method for the first four weeks of treatment and for four weeks after each dose increase, because the pill's absorption can be affected.

Mounjaro is also not licensed for under-18s. Age, alongside the clinical picture, is part of what the prescriber assesses. You can read how our prescribers approach that review on our Mounjaro treatment page.

On the cost side, private Mounjaro pricing in the UK has shifted since Eli Lilly raised list prices in September 2025. Our Mounjaro cost guide sets out what the market looks like now and what a legitimate price includes, useful context before you commit anywhere.

What happens if you're close to the threshold

A BMI sitting just below 30 is where people most often ask whether there is any flexibility. There isn't much on the absolute figure, but the 27–29.9 route with a qualifying condition is wider than it looks. Prediabetes is more prevalent than many people know. High blood pressure diagnosed at a GP check-up qualifies. If you have been told your cholesterol is elevated, that also counts. It is worth reviewing your GP records before assuming you don't meet the criteria.

If you are genuinely below BMI 27, Mounjaro is not the right route; our weight-loss treatment overview covers what other options are licensed in the UK and how they compare. And if you are wondering how tirzepatide stacks up against semaglutide on both criteria and outcomes, our tirzepatide comparison page addresses that directly.

If you meet the criteria and want a clinical assessment, a consultation with our prescribers is free and reviewed the same day a real clinician reads your answers, not software. Start your free consultation and we'll take it from there.