How Much Should I Lose Per Week on Mounjaro? (October 2026)

01 · The core answer

What is a realistic weekly loss on Mounjaro?

A realistic weekly loss is a small, uneven one that adds up over months, and there is no number per week that you are supposed to reach. 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 — think in months, not days, and judge progress by trend, not individual weigh-ins.² A week with a big drop, a week with nothing and a week where the scale creeps up can all sit inside a perfectly healthy downward trend.

If you want the same question answered in kilograms, our guide to how many kg per week covers it.

02 · The decision you are facing

Is my loss too fast or too slow?

Your loss is probably within the normal range if it is uneven but trending down over weeks. Slower early progress does not predict failure: the dose you respond to may still be ahead of you.¹ Equally, a sharp early drop is not a sign you are doing better than everyone else, because early loss includes water weight.¹³

Where loss feels unusually rapid, or you are struggling to eat enough or are persistently unwell, speak to your prescriber rather than pushing on; if nausea or vomiting is persistent or you cannot keep fluids down, contact your clinical team — dehydration needs prompt attention. Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle.¹³ Anything that does not fit that picture is worth raising, and you can report suspected side effects through the Yellow Card scheme.¹⁹

If loss feels slow, the structured check is the review point. 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 That is the clinical yardstick, rather than a weekly number.

03 · Next step

What should I do next?

If you are already on treatment, keep a simple record of your weight trend, appetite and any side effects, and bring it to your monthly review. If you are still deciding, our weight loss clinic explains how treatment works alongside diet and activity, and the Mounjaro pen page shows current doses and prices. All six doses are in stock, and a free consultation is reviewed by a GPhC-registered prescriber before anything is supplied.

Mounjaro (tirzepatide) is a prescription-only medicine. It is used alongside a reduced-calorie diet and increased physical activity. Individual results vary, and this page is information, not a substitute for medical advice.

04 · Why there is no weekly target

Why there is no weekly weight loss target on Mounjaro

There is no weekly target because tirzepatide changes appetite and eating behaviour, and the result depends on how you respond, what you eat and how you adjust over time. 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.¹

Tirzepatide is the first treatment of its kind to activate 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. In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.¹

Notice what that mechanism implies. The medicine makes a reduced-calorie diet easier to follow; it does not remove fat by itself. How much you eat, how consistently you move, how well you sleep and how your body adapts all feed into the number on the scale. Two people on the same dose can therefore see quite different weekly changes, and both can be on a normal course.

The dose also changes across treatment. You start low and step up as your prescriber judges appropriate, so the medicine's effect on appetite is not constant in the early months. A weekly figure quoted from someone on a high dose tells you almost nothing about what you should expect on the starting dose.

The honest position is that the clinical evidence is expressed as an average over a long period, and that average hides a wide spread of individual experiences.

A more useful habit is to ask three questions each month. Is the trend heading down over several weeks? Is my appetite meaningfully quieter than before I started? Am I tolerating the dose without troubling side effects? If the answers are yes, you are on track whatever last Tuesday's weigh-in said. If not, that is a conversation for your prescriber, and our weekly weight loss guide gives more context on what the pattern can look like.

05 · The first weeks

What to expect in the first weeks on 2.5mg

The first weeks on 2.5mg are about adjustment rather than results, and experiences differ widely. Some people notice appetite change and early loss in the first week, others feel little until a higher dose — both are normal.¹³

The starting dose exists to let your body get used to the medicine, not to deliver the largest effect. That is why the licence builds up through the strengths 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg, with steps taken after at least four weeks at the pace your prescriber considers suitable.¹ Reading a modest first month as a verdict on the whole course is a mistake.

Early loss includes water weight, so the trend over weeks matters more than any single weigh-in. Water shifts with food volume, salt, hormones and how recently you ate or drank, so the scale can move noticeably without any change in body fat. Equally, a week when your weight goes up slightly does not mean the medicine has stopped working.

Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects and usually settle.¹³ Many people find that eating smaller portions and stopping when full makes the early days easier. If nausea or vomiting is persistent or you cannot keep fluids down, contact your clinical team — dehydration needs prompt attention.

Practical things worth doing in this phase:

• Take your starting measurements and weight under the same conditions each time, so later comparisons mean something.
• Note your appetite and how full you feel after a normal meal, because appetite change is often the first sign the medicine is working.
• Keep protein and fluids up, and avoid judging the course by the first few readings.
• Write down questions for your first review rather than relying on memory.

Our fuller week-by-week guide walks through the stages in more detail.

06 · Reading the trial averages

What the SURMOUNT-1 averages mean for your week

The SURMOUNT-1 averages are measured over many months of treatment, so they describe where people ended up, not how fast they got there each week. 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

These are trial averages — individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.² An average combines people who lost a great deal with people who lost far less, and it also combines people on different doses. Nobody is the average.

The spread matters just as much as the middle. 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 So a large majority reached a clinically meaningful loss, while a smaller group went much further. Where you land depends on your own response.

Why not divide these figures into weeks? Because the loss was not delivered in even steps. Participants started on a low dose, stepped up, and the curve built over many months, so any per-week figure you calculate would misrepresent both the early phase and the later one.

It also helps to remember that percentages describe body weight, so the same percentage means a different amount on the scales for different people. Your prescriber can talk you through what a meaningful change looks like for your own starting point.

07 · Three months and the review point

What is a sensible expectation by three months?

By three months most people are still on the lower rungs of the dose ladder, so losses 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 12.²

A sensible 3-month expectation on a standard titration is mid single digits as a percentage of body weight, with wide individual variation.² That is the realistic figure to hold in your head when someone tells you what they lost in a fortnight.

Slower early progress does not predict failure — the dose you respond to may still be ahead of you.¹ If you have been on the same dose for some time with little change, your prescriber can discuss whether a step is appropriate.

The formal review sits further along. 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

Ongoing monthly reviews are part of our aftercare, so you are not left to interpret your own numbers alone. Your prescribing team looks at your dose, your side effects and your trend together, and repeat orders re-check suitability rather than shipping automatically.

08 · Plateaus and stalls

What to do when the scale stops moving

A stall is normal, and the right response is a calm review of the basics rather than a dose change on your own. Weight loss on Mounjaro is not linear — plateaus of a few weeks are normal and expected as the body adapts to a lower weight.¹¹

Within the licence, the responses are: review food intake honestly (portions drift back up), protect protein and activity, check the basics (sleep, alcohol), and discuss with your prescriber whether a dose step-up is appropriate if you are not yet at maximum.¹¹ It is worth taking each of those seriously in turn.

Portions are the most common culprit. As appetite quietens, people often settle into a routine, then drift to slightly larger servings or more snacking without noticing. A few days of honest tracking usually reveals it.

Sleep and alcohol are quieter influences. Neither is dramatic on its own, but together they can flatten a trend.

The step-up question is for your prescriber. If you are not yet at the maximum dose and are tolerating treatment well, a step may be reasonable. If you are already at your highest tolerated dose, the conversation shifts toward whether the current plan is working for you.

A plateau is not a reason to double doses or add unlicensed products.¹¹ Our healthy weight loss guide explains what a sustainable pace looks like more generally.

Finally, a plateau can be an opportunity to look at non-scale changes. Clothes fit, energy, appetite and blood pressure readings often move even when the scale pauses.

09 · Beyond the scales

Signs of progress that are not on the scale

Measurable health changes often show up before or alongside the number on the scale. 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 — but they are why prescribers talk about weight management as health management rather than appearance.² If you have a check-up with blood pressure or blood tests, those results can tell you more about progress than a stubborn week of weigh-ins.

People often ask whether a few pounds is noticeable, or where weight comes off first. Whether a change is visible depends on your starting size, your build and where you tend to carry weight. Clothes, belts and waist measurements usually register change before photos or mirrors do, and people who see you daily often notice later than someone who has not seen you for a while.

Useful non-scale markers include:

• How your clothes fit around the waist.
• How full you feel after an ordinary meal, and how quickly hunger returns.
• Your energy and how easily you manage everyday activity.
• Blood pressure, cholesterol and blood-sugar results, if your clinician checks them.

When you do weigh yourself, pick a consistent time and set-up, such as the same time of day, similar clothing and before eating. Your weight is naturally a little different at different times of day, so consistency matters more than whether you choose morning or night.

The GLPTrackr companion app, free for iOS and Android, lets you log weight and other details across your GLP-1 journey, which makes your trend easier to see and to share at a review. A line across several weeks is far more informative than any single reading.

10 · Safe pace, NHS and private

A safe pace, and how to get supported treatment

A safe pace is one where you feel well, eat adequately and are supported by regular clinical review, rather than one defined by a weekly number. 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.¹

Be wary of anyone promising a specific rate of loss, or offering to supply without a consultation or prescription. Counterfeit and unregulated products are a real risk, and the MHRA publishes alerts and runs the Yellow Card scheme for reporting suspected side effects or problem products.⁷ You can check any pharmacy on the GPhC register, and ours is GPhC 9012878.

On the NHS side, 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 (initially BMI 40+ with four or more qualifying conditions). Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.⁴⁶ Your GP can tell you where you sit in that process.

If you choose private treatment, our service works like this: a free online consultation, a review by a GPhC-registered prescriber, dispensing by our registered pharmacy, and free next-day tracked delivery in temperature-controlled packaging, with same-day dispatch when ordered by 3pm. Payment is taken when you place the order, and if the prescriber decides the treatment is not suitable, the order is refunded automatically in full. Genuine KwikPens come through official LillyDirect supply, and needles, a sharps bin and injection guidance come with every order.

On cost, the standard pen price depends on the dose, so you can plan around your own likely maintenance dose. A first year costs £2,711.88 if you stay on 5mg after your 2.5mg starting pen, up to £3,599.88 if you step up through every dose to 15mg, at standard prices. A new customer's first order is £40 less and every later order £25 less. You can see current prices on the Mounjaro pen page, or compare the cost side of things in our guide to what Mounjaro costs per week.

Whichever route you take, tell your prescriber about any new symptoms, and remember that pace is something you and your prescriber review together, not a race against a number.

11 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹