How Much Do You Need to Weigh to Get Mounjaro? (October 2026)

01 · The criteria

There is no minimum weight: BMI decides

Mounjaro has no minimum weight. It is licensed by BMI, because the same weight means something different for a shorter or taller person. A 100 kg adult can sit in a different BMI band from another adult at the same weight, so a single weight cut-off would not make clinical sense.

For weight management, Mounjaro is licensed for adults with a BMI of 30 or above. It is also licensed for a BMI between 27 and 30 with at least one weight-related condition, such as high blood pressure, high cholesterol, obstructive sleep apnoea, cardiovascular disease, prediabetes or type 2 diabetes.¹¹¹ It must be used alongside a reduced-calorie diet and increased physical activity.¹

This is why "how much do I need to weigh" has no single answer. A prescriber assesses your BMI, medical history and current medicines before deciding whether Mounjaro is suitable.¹ For a wider checklist, see what you need to get Mounjaro.

02 · Private treatment

Getting Mounjaro privately if you meet the criteria

If your BMI is within the licensed range, you can start with a free online consultation. It is a short health questionnaire, with no charge and no obligation. A GPhC-registered prescriber reviews it, and a prescriber's judgement decides the outcome, not a scoring script. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.

The Mounjaro pen starts at £169.99 for the 2.5mg starting dose. A new customer saves £40 on their first order at any dose with code FIRST40, so your first 2.5mg pen is £129.99. After that, an automatic £25 reorder discount applies to every future order (code DOSE25). All six doses are in stock. For the full cost picture, see how much Mounjaro costs in the UK.

Across the UK pharmacies we track, a 2.5mg starting pen ranges from £143.96 to £179.99 (checked 11 October 2026). Compare like for like, and confirm that any seller is a registered pharmacy.

03 · How it works

How ordering works

Ordering follows three steps, and you can start your free consultation whenever you are ready.

• Free online consultation: a short health questionnaire, with no charge and no obligation.
• Prescriber review: a GPhC-registered prescriber reviews your answers. Declined consultations are refunded automatically in full.
• Dispensing and delivery: our registered pharmacy dispenses your order. Orders placed by 3pm are dispatched the same day, with free next-day tracked delivery in temperature-controlled packaging.

Monthly reviews, dose-titration and side-effect support are part of ongoing care. Repeat orders re-check suitability, and nothing ships automatically. You can browse Buy Mounjaro for the wider picture.

04 · BMI and the licence

Why BMI, not weight, is used

BMI is the measure the Mounjaro licence is written around. The licence sets two routes for weight management: a BMI of 30 or above, or a BMI between 27 and 30 with at least one weight-related condition.¹

If you are in the 27 to 30 band, the condition matters as much as the number. Tell the prescriber about any diagnosis you have, even if you do not think it is related to your weight.

Someone with a very high weight and someone with a lower weight can both qualify, because the licence is not set by weight. Equally, being a few kilograms below a BMI threshold changes the answer, so the threshold is applied to your measurements as a whole. The licence is the same for everyone. The prescriber's job is to decide whether the medicine is suitable for you.¹

05 · NHS eligibility

How to qualify for Mounjaro on the NHS

Mounjaro is available on the NHS, but access is being phased in over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition.⁴ The NHS primary-care rollout began in June 2025 with the highest-need groups first, initially people with a BMI of 40 or above and four or more qualifying conditions.⁶

That means NHS criteria are tighter than the licence. The licence allows treatment from a BMI of 30, or from 27 with a condition. NHS access follows the phased order, so someone who meets the licensed criteria may still not yet be in an eligible NHS group. Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.

If you want to explore the NHS route, ask your GP which group you fall into now and how the local rollout is progressing. The NHS medicine guide is a good starting point for general information.⁵

06 · Why people are refused

Why you might be refused Mounjaro

The most common reason is simple: your BMI and conditions fall outside the licensed criteria. A BMI under 30 without a weight-related condition, or under 27, does not meet the licence for weight management.¹

The second reason is safety. A prescriber assesses your medical history and current medicines before deciding whether Mounjaro is suitable.¹ Some medicines need attention. Mounjaro can reduce absorption of oral contraceptives, because stomach emptying slows, so your prescriber will discuss this with you.⁷ The SmPC advises switching to a non-oral method, or adding a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.¹ If you take insulin or a sulfonylurea, doses may need adjusting because of the risk of low blood sugar.¹¹

For who should not take it, see the patient information leaflet.¹³ You should not take Mounjaro if you are allergic to tirzepatide or any of its ingredients, and it should not be used during pregnancy or while trying to conceive. Your prescriber will take extra care, or may recommend against treatment, if you have a history of pancreatitis, severe gut or digestive disease, diabetic retinopathy, or gallbladder problems. Mounjaro must not be used during pregnancy, and it should be stopped at least one month before trying to conceive. Ask your prescriber about any specific concern.

If a consultation is declined, you are refunded automatically in full. Giving inaccurate measurements to get around the criteria puts your safety at risk, and we explain why in our guide on whether you can lie to get Mounjaro.

07 · What results to expect

What trial results look like

In the SURMOUNT-1 trial of 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks. The comparison group, using lifestyle changes alone, lost 3.1%.² These are trial averages, and individual results vary.

At 72 weeks, 85% of participants on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5% of their body weight. Half of participants on 10mg and 57% on 15mg lost at least 20%.²

As a worked example only, for someone starting at 100 kg, 20.9% is about 21 kg. Treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.²

Your prescriber reviews progress with you at monthly check-ins. Protein and nutrition matter during treatment, and our guide on how much protein you need on Mounjaro covers it.

08 · How the medicine works

What Mounjaro is and how it works

Mounjaro is the brand name for tirzepatide, a once-weekly injectable prescription medicine made by Eli Lilly. In the UK it is licensed for weight management in adults and for type 2 diabetes. It comes as a pre-filled multi-dose pen (KwikPen) in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.¹

Tirzepatide activates two natural gut-hormone receptors at once, GIP and GLP-1. Together these help regulate appetite, slow how quickly the stomach empties, and improve the way the body responds to insulin. Most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.¹

This dual action distinguishes Mounjaro from single-action GLP-1 medicines such as semaglutide (Wegovy and Ozempic). Tirzepatide has a half-life of about five days, so after a final dose it takes roughly 4 to 5 weeks to clear the system.¹

09 · If you do not qualify

What to do if you fall outside the criteria

If your BMI is under the licensed thresholds, Mounjaro is not the right route for weight management. That includes people who are only slightly overweight or who have a small amount of weight to lose. The licence is for adults who meet the BMI criteria, so a prescriber would not be able to supply it outside them.¹

Ozempic is semaglutide licensed for type 2 diabetes — it is not a UK weight-loss medicine, and prescribing it privately for weight loss is off-label. A regulated UK pharmacy will not supply Ozempic for weight loss. Ask your GP or prescriber what applies to that product.

Your options are practical ones. Speak to your GP about a structured weight-management plan, and recheck your BMI if your circumstances change, for example if a new diagnosis such as high blood pressure appears. You can also look at our weight loss treatments overview to see what else is available, and ask the prescribing team which, if any, fits your situation.