What BMI do I need for Mounjaro privately?

Private prescribing follows the same licensed range as the NHS: a BMI of 30 or above, or 27 to 29.9 with at least one weight-related condition. A private assessment will confirm your actual eligibility, including your medical history, not BMI alone.

Why don't I qualify for Mounjaro on the NHS if I meet the licence?

The licence sets the widest possible range a prescriber can use. NHS funding is being introduced in phases, prioritising the highest combined BMI and comorbidity burden first, so many people who meet the licence do not yet meet the current NHS funding criteria.

Can I check my BMI before contacting the pharmacy?

Yes. Our free BMI calculator runs in your browser and gives you an instant result against the thresholds above. It is a sensible first step, though a full clinical assessment is always needed before any prescribing decision.

7 min read

What BMI Do You Need for Mounjaro in the UK? Private vs NHS Thresholds

Q: What BMI do you need for Mounjaro in the UK?

The UK licence covers a BMI of 30 or above, or 27 to 29.9 with a weight-related condition such as high blood pressure or type 2 diabetes. NHS funding is much tighter and is currently limited to a BMI of 40 or above with 4 or more weight-related conditions, widening in phases through 2026 and 2027.

Q: Is the Mounjaro BMI threshold lower for certain ethnic groups?

Yes. NICE guidance lowers the BMI threshold by 2.5 points for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background, because BMI underestimates health risk in these groups at the same number.

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A pharmacist beside clinical scales and a height measure explaining BMI to a patient in a UK pharmacy consultation room

Quick answer

Mounjaro (tirzepatide) is licensed in the UK for adults with a BMI of 30 or above, or 27 to 29.9 with a weight-related health condition such as high blood pressure or type 2 diabetes. That is the threshold a private prescriber works to. NHS-funded Mounjaro is far tighter: as of 2026 it is generally restricted to a BMI of 40 or above with four weight-related conditions, widening in stages through to 2027. If you fall between those two lines, you meet the licence but not yet the NHS funding criteria, which is the gap most people asking about BMI and Mounjaro are actually running into.

What BMI does Mounjaro's UK licence require?

Mounjaro's UK marketing authorisation, the licence set by the medicines regulator and confirmed in NICE's technology appraisal TA1026, covers adults with an initial BMI of 30 or more (classed as obesity), or a BMI of 27 up to 29.9 if you also have at least one weight-related condition, such as high blood pressure, high cholesterol, obstructive sleep apnoea, cardiovascular disease or type 2 diabetes. That is the widest a prescriber can legally go, whether the prescription is NHS or private.

If you are of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background, the threshold is usually lowered by 2.5 points, because BMI is known to underestimate health risk in these groups at the same number. So a BMI of 27.5, for example, may already meet the obesity threshold rather than the overweight-plus-comorbidity one.

This licence is what a private weight management assessment goes by. It is not the same as what the NHS will currently fund, which is a much narrower slice of that population.

What BMI does the NHS actually require for free Mounjaro?

This is where most of the confusion comes in, and it is worth being blunt about it: the NHS is not yet funding Mounjaro for everyone who meets the licence. NHS England's interim commissioning guidance sets out a phased rollout, prioritising the people with the highest combined BMI and comorbidity burden first:

Now: a BMI of 40 or more, with 4 or more of the listed weight-related conditions (high blood pressure, dyslipidaemia, obstructive sleep apnoea, cardiovascular disease, type 2 diabetes).
From around June 2026: a BMI of 35 to 39.9, still with 4 or more of those conditions.
From around March 2027: a BMI of 40 or more, but now only 3 of those conditions needed rather than 4.

The same 2.5-point ethnicity adjustment applies here too. Full eligibility for the licensed population is expected to take up to 12 years to reach everyone, so a BMI of 30 with one comorbidity, which meets the licence, is unlikely to get NHS-funded Mounjaro any time soon through this route. That gap between "licensed for" and "NHS-funded for" is exactly what drives most patients into asking about private access instead.

What I tell patients at the counter

A lady in her 40s came in last month having read online that Mounjaro needs a BMI of 27. She was 28.4, no other health conditions, and had already worked out privately that she qualified. What she had not accounted for is that the 27 threshold only applies if you also have a weight-related condition. Without one, the licence needs a BMI of 30. She was disappointed, but it meant she avoided paying for a private consultation she would not have passed, and we talked through what else might help her in the meantime, including our free NHS Health Check to look at her blood pressure and cholesterol properly rather than guessing.

The most useful first step before booking anything is working out your own BMI properly, weight and height alone, calculated correctly. We built a free calculator for exactly this.

Check your BMI before you enquire

Our BMI calculator runs entirely in your browser: nothing is sent anywhere, and you get an instant result plus where that puts you against the thresholds above. It will not tell you whether you will be prescribed Mounjaro, that always needs a proper clinical assessment covering your full medical history, not just a number, but it is a sensible first check before you contact us.

Our weight management booking is temporarily closed while we review capacity. If you have checked your BMI and want to know more about Mounjaro specifically, including how it works and what to expect, our Mounjaro information page has the detail, or you can contact us directly and we will get back to you as soon as appointments reopen.

Mounjaro is not suitable for everyone

BMI is only one part of the picture. Mounjaro is not recommended if you are pregnant, trying to become pregnant, or breastfeeding, and it is not a medicine to take for cosmetic weight loss if you do not meet the licensed BMI range. If you take the contraceptive pill, tirzepatide can reduce how well your body absorbs it, so an additional method such as condoms is recommended, particularly around dose increases. Any proper assessment will cover this before a prescription is considered. If you have concerns about side effects after starting any GLP-1 medicine, or you feel unwell in a way that worries you, contact your GP, call 111, or in an emergency call 999.