How Many Kilos Can You Lose on Mounjaro? (October 2026)

01 · The core answer

How many kilos can you lose on Mounjaro?

The honest answer is a percentage of your starting weight, which you then translate into kilos yourself. 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, compared with 3.1% with lifestyle changes alone.²

To estimate your own figure, take your starting weight in kilos and apply the percentage for the dose you might reach. Someone with a higher starting weight will lose more kilos from the same percentage than someone with a lower one. That is why a single universal kilo figure would mislead you.

These are trial averages. Individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.² Some people lose less than the average and some lose more. Our guide to how much you can lose overall covers the same figures from the percentage angle.

02 · Your decision

Is this realistic for you, and what next?

If you are deciding whether to start, the useful question is not "how many kilos will I lose" but "what percentage is a realistic and healthy aim for me, and can I sustain the habits that go with it?" A prescriber can talk this through against your health history.

If you meet the licensed criteria and want to go ahead, you can start with a free online consultation reviewed by a GPhC-registered prescriber on our Mounjaro pen page. Your first 2.5mg pen costs £129.99 with code FIRST40 (standard price £169.99). Our weight loss clinic page explains the wider service.

03 · Trial results explained

What the SURMOUNT-1 trial actually showed

SURMOUNT-1 is the main trial behind the headline figures you see quoted. 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, compared with 3.1% with lifestyle changes alone.²

These figures are averages across a large group. Some participants lost much more, some much less. Trial averages do not predict your own result, so treat them as a guide to the general shape of progress rather than a target you must hit.

The trial also reported how many people reached meaningful thresholds. 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% of their body weight.²

Notice what this tells you. Most people on any of these doses lost at least 5% of their body weight, and half of participants on 10mg and 57% on 15mg lost at least 20%. Planning around the average is more realistic than planning around the top end. For a version of this question framed in kilograms, see how many kg you can lose.

04 · Turning percentages into kilos

How to turn a percentage into your own kilos

Multiply your starting weight in kilos by the percentage loss, then divide by 100. For example, for someone starting at 100 kg, 20.9% is about 21 kg. That simple arithmetic is all there is, and it is why two people on the same dose can see very different kilo figures from the same percentage result.

Treat the output as a rough planning range, not a forecast. The trial percentages are averages for groups on a given dose at 72 weeks. They are not a promise for any individual, and they assume time on treatment and the lifestyle changes the trial paired with the medicine.²

A few cautions help you avoid disappointment:

• Use the percentage for the dose you realistically expect to reach, not automatically the highest.
• Remember that many people do not stay at the top dose. Your prescriber chooses the maintenance dose with you.
• Do not expect the final figure early. The averages come from the end of a long trial, not the first weeks.
• Judge progress by trend over weeks, not one weigh-in.

Some people prefer stones and pounds. Our page on how many stone you can lose approaches the same numbers in those units.

05 · Pace: month by month

How fast do the kilos come off?

Weight loss on Mounjaro is gradual by design. The first weeks on 2.5mg are an adjustment phase and losses are usually modest; most measurable progress builds from 5mg onward, month by month.¹ Trials measured results at 72 weeks, so think in months, not days, and judge progress by trend, not individual weigh-ins.

The dose ladder explains the pattern. You start on the lowest strength and step up after at least 4 weeks on each dose, depending on how you respond and tolerate it, through 5mg, 7.5mg, 10mg and 12.5mg up to a maximum of 15mg. Because each step takes time, the largest effects arrive later in treatment.¹

Three months in, most people are still on the lower rungs of the dose ladder, so trial-average losses at this stage are modest compared with the headline figures: in SURMOUNT-1, average weight loss built month by month, with the full 15–21% averages measured at 72 weeks, not 12. A sensible 3-month expectation on a standard titration is mid single digits as a percentage of body weight, with wide individual variation.²

Slower early progress does not predict failure, because the dose you respond to may still be ahead of you. If you want a weekly view of this, see how many kilos a week people lose and the related page on kg per week.

06 · The early weeks

What is normal in the first weeks

The 2.5mg starting weeks are about adjustment, and experiences differ widely: some people notice appetite change and early loss in week one, others feel little until a higher dose. Both are normal.¹

Early loss includes water weight, so the trend over weeks matters more than any single weigh-in. Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle.¹³

A small early change, or even none, is not a sign the medicine is not working.

Practical habits for the early phase:

• Weigh at a consistent time, and look at the direction over several weeks.
• Eat smaller, regular meals if you feel full quickly.
• Keep fluids up and report anything that worries you to your prescriber.
• Use the early weeks to build food and activity habits you can keep.

07 · Plateaus and slow progress

Plateaus: when the scales stop moving

Weight loss on Mounjaro is not linear. Plateaus of a few weeks are normal and expected as the body adapts to a lower weight.

Within the licence, the responses are practical rather than dramatic:

• Review food intake honestly, because portions drift back up.
• Protect protein and activity.
• Check the basics, including sleep and alcohol.
• Discuss with your prescriber whether a dose step-up is appropriate if you are not yet at maximum.

A plateau is not a reason to double doses or add unlicensed products.

Your response is also reviewed formally. Treatment response is reviewed by your prescriber: if you have lost less than 5% of your starting weight after 6 months on the highest dose you can tolerate, your prescriber will discuss whether continuing or stopping is right for you.¹

If you are worried about stalled progress, our page on what you can realistically expect sets out a sensible mindset.

08 · Staying on 2.5mg

Can you stay on 2.5mg and still lose weight?

Some people do lose weight on 2.5mg, but it is designed as a starting dose rather than the strength where most progress is made. The first weeks on 2.5mg are an adjustment phase and losses are usually modest; most measurable progress builds from 5mg onward.¹

Experiences differ widely, and your prescriber decides with you whether to step up, based on how you respond and tolerate treatment. Staying longer on a lower dose can be sensible if side effects are troublesome. It should be a decision made with your prescriber, not a way to stretch supplies.

If you are not yet at the maximum dose and progress has stalled, a step-up may be appropriate. That conversation belongs in your regular review, which is part of the aftercare included with our service.

09 · Health changes beyond kilos

Beyond the scales

Kilos are not the only outcome that matters. In trials, weight loss on tirzepatide came with average improvements in waist size, blood pressure, cholesterol and blood-sugar measures, and most participants with prediabetes returned to normal blood-sugar levels.²

These are trial-average secondary outcomes, not promises. They are why prescribers talk about weight management as health management rather than appearance. If your scale is moving slowly but your clothes fit differently or your readings are improving, that is still meaningful progress.

10 · Stopping and access

After you stop, and getting access

Tirzepatide has a half-life of about five days, so after a final dose it takes roughly four to five weeks to clear the system. There is no way to speed this up, and nothing needs doing while it clears.¹ Plan your lifestyle habits so they carry on after treatment. In SURMOUNT-4, people who stopped tirzepatide after 36 weeks regained on average 14% of body weight over the following year, while those who continued lost a further 5.5% on average. Stopping should always be planned with your prescriber.¹⁴

On access, 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, and the NHS primary-care rollout began in June 2025 with the highest-need groups first.⁴ Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.⁶

Mounjaro is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. It is used alongside a reduced-calorie diet and increased physical activity. Individual results vary. This page is information, not a substitute for medical advice. We are GPhC-registered (9012878), and our Mounjaro comes through official LillyDirect supply.