Why You Might Not Be Eligible for Mounjaro Right Now

Does your BMI actually meet the licensed threshold?

The UK licence for tirzepatide sets the starting point at a BMI of 30 or above for weight management, or a BMI of 27 or above if you also live with at least one weight-related condition, for example, prediabetes, hypertension, high cholesterol, or obstructive sleep apnoea. If your BMI sits below these figures, the medicine isn't licensed for your situation, and a responsible prescriber won't issue a prescription. It's not a judgement call; it's what the clinical authorisation allows.

It's worth checking your number properly. The NHS BMI calculator gives you a reliable figure, and it matters more than an approximation. For adults from South Asian, Chinese, Middle Eastern, Black African or African-Caribbean backgrounds, UK guidance sets the thresholds 2.5 kg/m² lower, so the 30 threshold becomes 27.5, and the 27 threshold becomes 24.5. If you haven't factored that in, your position may be different from what you assumed. Our BMI guide for Mounjaro walks through exactly how those numbers apply.

BMI is one part of the picture. A prescriber also reviews the rest of your health history, any existing conditions, and what you're already taking. Hitting the BMI number is necessary but not on its own sufficient.

Which medical conditions can rule Mounjaro out?

Some medical histories make tirzepatide unsuitable regardless of BMI. A personal or family history of medullary thyroid carcinoma (a specific type of thyroid cancer) or Multiple Endocrine Neoplasia type 2 (MEN2) is a contraindication, as is a history of pancreatitis in certain circumstances. Severe gastrointestinal conditions that affect how medicines are absorbed may also be a reason your prescriber flags a concern.

Mounjaro is not licensed for use during pregnancy or breastfeeding, and is not recommended for people who are actively trying to conceive. It is not licensed for anyone under 18. These aren't arbitrary rules, tirzepatide's effects in those situations haven't been established as safe, and the licence reflects that. If any of these apply, a prescriber will explain the reasoning and may suggest reviewing things once your circumstances change.

There are also medicines that interact in ways worth discussing. The most practical example is oral contraceptives: MHRA guidance and clinical evidence indicate that tirzepatide can reduce their absorption, so women taking the pill are advised to add a non-oral method of contraception during the first four weeks of treatment and for four weeks after each dose increase. That interaction doesn't stop you starting treatment; it's something a prescriber discusses with you. More detail on eligibility factors is covered on our Mounjaro eligibility criteria page.

NHS criteria versus private: why they're very different things

A lot of people discover they're not eligible for Mounjaro on the NHS and assume that closes the door entirely. It doesn't. NICE's recommendation for tirzepatide (TA1026) sets NHS thresholds at BMI 35 or above alongside at least one qualifying comorbidity, within a phased rollout. The current NHS cohort covers people with a BMI of 40 or above plus four or more of five specific conditions; further cohorts are opening gradually through 2026 and into 2027. If you don't meet those particular criteria today, you are in the majority, the NHS programme covers a very narrow group at this stage.

Private eligibility, by contrast, follows the licensed thresholds in the SmPC: a BMI of 30 or above, or 27 or above with a weight-related condition. That's a much broader group. If you want to understand exactly what the private criteria cover, our Mounjaro weight loss eligibility page sets out the full requirements clearly. There's no waiting list for a private assessment, and a same-day review by a named prescriber means you'll have a clear answer the same day you apply, usually well before the school run.

If you want to understand where you stand without committing to anything, our Mounjaro eligibility overview explains both NHS and private routes side by side. For a full look at the treatment options available, the weight-loss treatments page covers what's currently dispensed and the process from start to finish.

Can anything change your eligibility status?

Sometimes, yes. The most straightforward situation is someone whose BMI is just below the threshold: if your weight changes (in either direction) your eligibility changes with it. Similarly, if a new health condition is diagnosed (or one is confirmed that wasn't previously documented), the eligibility picture shifts. Hypertension that's formally recorded, for instance, could move someone from below the BMI-27-without-conditions threshold to above the BMI-27-with-one-condition threshold.

Medical decisions are also time-dependent. A previous history of pancreatitis, for example, is assessed carefully, and a prescriber may take a different view depending on how long ago it occurred and how it resolved. If you're weighing up your own situation and wondering whether you are suitable for Mounjaro, that page works through the personal and medical factors a prescriber considers. Our eligibility assessment guide explains what information a prescriber needs to make that call.

The honest answer is that this is a conversation worth having with a clinician rather than a checklist you run through alone. If you'd like a proper assessment of where you stand, our weight-loss service offers a free consultation reviewed by a GPhC-registered Independent Prescriber, no obligation, and a clear outcome either way. You can also read more about our clinical team and the standards they work to. If you have questions before starting, our FAQs cover the most common ones.