Not Losing Weight on 10mg Mounjaro? Reasons and Next Steps (October 2026)

01 · Start here

Is a stall on 10mg a real problem?

Often it is a slower patch rather than a true stall, and the first job is to work out which one you are in. Weight loss on Mounjaro is gradual by design, and results are best judged over weeks and months rather than day to day.¹

Ask yourself a few plain questions. Has the scale trend been flat over several weeks, or just a few days? Has your appetite changed from how it felt earlier on? Have you missed or delayed injections? Have your eating habits drifted without you noticing? Your answers point towards the cause far better than any generic list.

Day-to-day weight moves for many reasons unrelated to fat. Early loss on treatment includes water weight, so the trend over weeks matters more than any single weigh-in.¹ The same logic applies later: a flat week or two does not tell you much on its own.

02 · What to expect

What the trial results say about 10mg

In the SURMOUNT-1 trial, people on 10mg lost a substantial amount on average, but the spread between individuals was wide. 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 Averages also hide people who lost less than the headline figure, which is why a slower result than you hoped for is not unusual.

At 72 weeks, 85% of participants on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5% of their body weight.² Half of participants on 10mg and 57% on 15mg lost at least 20% of their body weight.² Note the timescale: the trial ran for 72 weeks, so a plateau a few months in sits well inside the period over which results were measured.

03 · Your next step

What to do next if you are stuck on 10mg

The sensible next step is a structured check of the basics, followed by a conversation with your prescriber rather than a self-directed dose change.

If you are a customer and want a review of your plan, our prescribing team offers ongoing monthly reviews. Everything starts with a free consultation on the Mounjaro pen page, where current strengths and prices are listed; the 10mg pen is £290.99 per month at the standard price, and it is in stock. For wider support, see our weight loss clinic.

Related guide: Why Am I Not Losing Weight On Mounjaro UK: Guide.

04 · Reasons progress slows

Common reasons progress slows on 10mg

Progress usually slows for a mix of ordinary reasons rather than a single dramatic one. The ones worth checking first are practical and within your control, which is good news because you can test them yourself.

First, the medicine supports a reduced-calorie diet; it does not replace one. Mounjaro helps most people feel fuller sooner and less hungry between meals, which makes eating less easier.¹ Feeling less hungry is not the same as eating less, though. Portions can grow, snacks can return, and drinks can add up without registering as food.

Second, the pace of loss changes over a course of treatment. Early weeks can show quick movement that includes water, and later progress is typically steadier. Seeing the scale move more slowly than in the first months can feel like failure when it is simply a different phase.

Third, timing. If you stepped up to 10mg recently, you may not have given it enough weeks to judge. The licensed ladder moves in steps at minimum intervals, and the dose you are on reflects how you responded and tolerated each step.¹

Fourth, consistency of the plan around the medicine: sleep, stress, activity and regular meals all shape how easy it is to stay in a reduced-calorie pattern. None of these are failings, but they are worth being honest about when you review your progress.

Finally, individual variation is real. Trial averages are averages, and people sit on both sides of them.² Some respond slowly and still make good progress over a longer period.

05 · Is 10mg enough?

Do you need a higher dose than 10mg?

Not necessarily, and the decision belongs with your prescriber. The licensed ladder runs up to 15mg, but many people settle at a maintenance dose of 5mg, 10mg or 15mg, and higher is not automatically better.¹ The right pace is guided by how you respond and how well you tolerate each step.

The licensed titration works like this: Everyone starts Mounjaro on 2.5mg once a week. After at least 4 weeks the dose increases to 5mg, and can then step up by 2.5mg at a minimum of 4-week intervals (7.5mg, 10mg, 12.5mg) up to a maximum of 15mg weekly, depending on how you respond and tolerate it.¹ A step up is possible within the licence, but it is a clinical decision that depends on your tolerance and your goals, not simply on a stalled scale.

Moving up rapidly because of impatience could leave you with more side effects and no better outcome. If you are comparing what happens at other strengths, our pages on stalling on 7.5mg and stalling on 12.5mg show how the same questions play out at neighbouring doses.

06 · Official response review

The 6-month response review

There is a formal checkpoint for exactly this situation. 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

Notice the wording: the highest tolerated dose. For some people that is 10mg, because higher steps cause side effects they would rather avoid. For others it is a higher strength. Either way, the review looks at your overall response, not a single number on a bad week.

This is a discussion, not a verdict. Outcomes of that conversation can include staying the course, adjusting the plan, or stopping if the treatment is not right for you. Come prepared with your weight trend, your injection dates, a short food diary and any side effects, since these let the prescriber give you tailored advice.

Earlier on, the picture is different. Judging progress by trend rather than by individual weigh-ins is the sound approach, because trials measured results at 72 weeks and the pace is meant to be measured in months, not days.¹

07 · Injection habits to check

Injection habits worth checking

Small slips in how you use the pen are an easy thing to rule out. Mounjaro is injected under the skin once a week, on the same day each week, at any time of day, with or without food.¹ There is no best time of day, so consistency of day matters more than the hour.

Licensed injection sites are the stomach area (at least 5cm from the belly button), the front of the thigh, or the back of the upper arm if someone else gives the injection, and you should rotate the site with each dose.¹³

If you miss a dose, take it as soon as you can within 4 days (96 hours) of the scheduled time, then carry on with your usual day. If more than 4 days have passed, skip the missed dose entirely and take the next one on your normal day, and never take two doses within 3 days of each other.¹ You can change your injection day if needed, as long as there are at least 3 days between two doses.¹

Storage matters too. Keep pens in a fridge at 2–8°C and never freeze them. Once in use, a pen can be kept out of the fridge at a temperature not above 30°C for up to 30 days after first use, and must then be thrown away.¹ Do not use a pen that has been above 30°C or has been frozen; ask the pharmacy for advice.

08 · Diet and activity audit

A practical diet and activity audit

A short, honest audit often explains more than any theory. Mounjaro is used alongside a reduced-calorie diet and increased physical activity, so the audit looks at both.² Do it for a couple of weeks without changing anything first; you want to see your real pattern, not your ideal one.

Write down everything you eat and drink, including drinks with calories, sauces, snacks eaten standing up and portions eaten because they were there. Many people find that smaller meals have gradually grown back towards their old size as appetite settled. That is a human pattern, not a character flaw.

Look at when you eat. If appetite is quiet in the day and returns strongly in the evening, that tells you where the calories are going. A planned, satisfying meal structure often works better than relying on low appetite to do all the work.

Then look at movement. You do not need extreme exercise. A routine you can keep up, built around walking, strength work or whatever you enjoy, is the realistic aim. Activity supports the plan whatever the scale shows.

Bring the diary to your review. It gives your prescriber something concrete to work with and often points to a simple adjustment. If nausea or low appetite is making it hard to eat properly at all, that is a different problem; our page on not eating but not losing weight covers it.

09 · How Mounjaro works

How tirzepatide works for weight loss

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.¹ In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.

That description matters for a stall. The medicine changes how hungry you feel and how quickly you feel full; it does not remove the link between what you eat and what you weigh. If you are under-eating, over-eating, or somewhere in between, the outcome follows.

This dual action distinguishes Mounjaro from single-action GLP-1 medicines such as semaglutide.¹ If you are weighing up a different medicine after a long plateau, our page on switching from semaglutide to tirzepatide explains the direction of that decision, and the wider guides on GLP-1 weight loss plateaus and stalls with GLP-1 treatment cover the class as a whole.

10 · Weight gain and stopping

Gaining weight, stopping and keeping weight off

If the scale is going up rather than just flat, speak to your prescriber rather than waiting. Short-term rises can reflect fluid or timing, but a sustained upward trend deserves a proper review of diet, activity, injection routine and anything else that has changed in your life or health.

When to stop is a decision to make with your prescriber, not alone. Reasons to talk about stopping include side effects you cannot tolerate or a poor response at your review. If you do stop, 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

Keeping weight off afterwards depends on the habits you build while on treatment. Stopping should always be planned with your prescriber, with diet and activity habits ready to carry the load. 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 treatment lost a further 5.5% on average.

Honest expectations help here. Treatment is a support for lifestyle change rather than a replacement for it, so the most useful preparation is learning what a sustainable reduced-calorie diet and regular activity look like for you.

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

12 · NHS and private routes

Where NHS and private care fit

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).⁴⁶ Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.

Whichever route you use, a stall is best handled with the clinician who prescribes your medicine, since they hold your history. With us, that means the prescribing team that reviews your progress, and customers can reach support Monday to Friday, 9am to 5pm.

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, and individual results vary. This page is information, not a substitute for medical advice. Report any side effect you suspect via the Yellow Card scheme.¹⁹