At What BMI Do Prescribers Stop Mounjaro Treatment?

What the official guidance says about starting, and stopping

NICE's appraisal of tirzepatide, published in December 2024 and updated in September 2025, is the clearest official reference on this. It recommends tirzepatide for adults with a BMI of 35 or above plus at least one weight-related comorbidity, for NHS use. If you want to understand what BMI you need for Mounjaro before going further, those figures are worth reading first. The licensed eligibility used in private prescribing is slightly broader: BMI 30 or above, or 27 or above with a qualifying condition such as high blood pressure, type 2 diabetes, high cholesterol, obstructive sleep apnoea or cardiovascular disease.

Neither the licence nor the NICE appraisal sets a maximum BMI above which prescribing must stop. A BMI of 60, 70 or beyond does not by itself disqualify someone. What the guidance does contain is a stopping rule based on clinical response: if a patient has not lost at least 5% of their body weight after six months at the highest dose they can tolerate, the case for continuing the medicine should be reviewed. That review involves the prescriber weighing up the whole picture, not simply reading a number off a set of scales.

The recommendations chapter of TA1026 also notes that thresholds are reduced by 2.5 kg/m² for people of South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds, reflecting evidence that weight-related health risks occur at lower BMI levels in those groups.

When a prescriber genuinely might not start or continue treatment

The conditions that lead a prescriber to pause or stop Mounjaro are clinical, not arithmetic. Contraindications listed in the tirzepatide SmPC on the eMC include a personal or family history of medullary thyroid carcinoma, Multiple Endocrine Neoplasia syndrome type 2, and a history of pancreatitis. Severe gastrointestinal disease, certain gallbladder conditions, and pregnancy are further reasons a prescriber would not initiate or would stop the medicine.

At repeat prescription stage, the clinical review is where continuation is genuinely assessed. At nume, a named prescriber reads every repeat request before anything is dispensed, there is no auto-renewal and no algorithm waving it through. If someone's circumstances have changed, their weight trajectory suggests the medicine is not working for them, or a new health concern has surfaced, the prescriber decides accordingly. For anyone wondering about the cost implications of long-term treatment, our Mounjaro cost page sets out what private prescribing involves.

BMI is one data point. It has always been a blunt instrument: two people with an identical BMI can have very different metabolic risk profiles. A prescriber looking at whether to continue treatment will weigh response, tolerability, the presence of comorbidities, and the patient's own goals.

What happens when a BMI drops below the starting threshold during treatment

This is the question our prescribers hear fairly often, and it catches people by surprise. The NHS England guidance on weight management injections does not direct prescribers to stop Mounjaro the moment someone's BMI falls below 30. The licensed indication does not contain a rule like that. What it does mean is that the clinical rationale for continuing shifts: if someone's BMI is now 27 and they have no remaining weight-related comorbidities, the prescriber needs to think carefully about whether the risk-benefit balance still favours treatment.

In practice, people who lose significant weight on tirzepatide typically still have metabolic health reasons to continue, at least for a period. Weight loss of 20% or more (as seen in the SURMOUNT-1 trial, which ran for 72 weeks in thousands of adults with obesity) does not happen overnight, and the period of weight maintenance after active loss is clinically meaningful. If your BMI has dropped into the healthy range, that conversation with your prescriber is worth having honestly rather than assuming either that treatment must stop or that it can carry on indefinitely.

If you want to understand what BMI you need to get Mounjaro before you reach that conversation, those figures are worth reading first, alongside what your BMI needs to be for Mounjaro as eligibility is assessed more broadly. The NHS BMI calculator is a practical starting point for checking your own figure: the NHS BMI tool gives you an instant reading you can bring to a consultation.

Starting a conversation rather than waiting for a ceiling that doesn't exist

There is no magic BMI number printed in the guidance that triggers an automatic stop. Treatment decisions at every stage (start, continue, reduce, stop) belong to a prescriber who knows your history. The stopping rule in the evidence is about response: five percent weight loss in six months is the line the NICE committee drew, not a BMI ceiling.

If you're unsure whether your current BMI or your clinical situation means Mounjaro is still appropriate, it can help to review what BMI to have for Mounjaro so you can go into that conversation with the right context, and our page on what BMI you have to be for Mounjaro covers how that eligibility is assessed in more detail. You can also read more about how treatment assessment works at nume, or browse the broader weight-loss treatment options we offer. Our FAQs cover many of the practical questions that come up between consultations. For anything specific, our support team is available seven days a week. When you're ready, you can speak to our prescribers through a free consultation, and if you order before noon on a weekday, a clinician reviews your case the same day.