UK Guide · Updated August 2026 · Reviewed by our superintendent pharmacist
The scales have stopped moving and you're still paying for treatment. Here's what's actually going on — and the checks a pharmacist runs before touching your dose.
The short answer
A plateau is normal physiology, not treatment failure. As you get lighter your body burns fewer calories, so the deficit that worked at your starting weight quietly closes. Most stalls of two to three weeks resolve on their own. If nothing has moved for four to six weeks, the usual culprits are missed or late doses, a pen that's been stored badly, portion creep, too little protein, lost muscle, poor sleep or alcohol — not the medicine giving up. Check your waist as well as the scales, because fat loss often continues while the number sits still. Only after those checks is a dose increase — Mounjaro rises in 2.5 mg steps to 15 mg, Wegovy to 2.4 mg or the new 7.2 mg high dose — the right conversation. In trials, weight didn't truly level off until around 60 to 72 weeks, so a stall at month three is almost never your ceiling.
This is the conversation we have most often at the pharmacy counter. Someone comes in for their monthly review, has lost 11 kg since January, and is genuinely upset — because the last three weeks have shown nothing. The first thing worth saying is that a plateau is not a sign the medicine has stopped working, and it is not a sign you've done something wrong.
A lighter body is a cheaper body to run. There is less tissue to keep warm, less mass to carry up the stairs, and the maths of your daily energy needs changes underneath you while your habits stay the same. Research on energy expenditure has found that total daily energy expenditure falls by roughly 15% after a 10% weight loss — and only about 60% of that drop is explained by the smaller body itself. The remainder is adaptive thermogenesis: your metabolism becoming quietly more efficient, alongside a rise in hunger signalling and a fall in leptin.
In other words, the deficit that produced 1 kg a week in month one may be close to zero by month six, without you changing a thing. That is not a flaw in Mounjaro or Wegovy. It is the reason chronic weight management needs ongoing treatment and review rather than a fixed course.
This matters because most people who think they've plateaued have simply hit a pause far earlier than the medicine's real ceiling. Here is what the pivotal studies recorded:
| Trial | Average weight loss | When it flattened |
|---|---|---|
| STEP 1 — semaglutide 2.4 mg | 14.9% at 68 weeks | Lowest point around week 60 |
| SURMOUNT-1 — tirzepatide 5 mg | 16.0% at 72 weeks | Plateau reached by week 72 |
| SURMOUNT-1 — tirzepatide 10 mg | 21.4% at 72 weeks | Near-plateau, still declining |
| SURMOUNT-1 — tirzepatide 15 mg | 22.5% at 72 weeks | Near-plateau, still declining |
| SURMOUNT-5 — head-to-head | 20.2% tirzepatide vs 13.7% semaglutide | Measured at 72 weeks |
Read that column on the right again. Weight kept falling for well over a year in these studies, and in the higher tirzepatide groups it had not fully levelled off even at 72 weeks. Trial averages are not promises — individual results vary widely and these were carefully supported participants — but they make the point clearly: a three-week stall at month four is not your ceiling.
| Signal | Temporary stall | Genuine plateau |
|---|---|---|
| How long | 2–3 weeks | 6+ weeks of no change |
| Waist measurement | Often still shrinking | Stable too |
| Time on treatment | Any point, often after a dose step | Usually 12+ months in |
| Appetite | Still noticeably suppressed | Hunger has clearly returned |
| Usual cause | Fluid, constipation, cycle, new muscle | Energy needs have met your intake |
| What to do | Hold steady, keep measuring | Book a pharmacist review |
Body weight is a noisy number. A salty takeaway, a few days of constipation — common on GLP-1 treatment — a menstrual cycle or a new gym habit can each hide two or three weeks of genuine fat loss. This is why we weigh patients on the same scales at the same pharmacy each month and take a tape measure to the waist. If your waist is still going down, nothing is broken.
In our experience, most stalls trace back to something on this list rather than to the medicine losing its effect. Work through it honestly before you consider paying for a higher dose.
Muscle is metabolically expensive tissue, so losing it lowers the calories you burn at rest and brings your plateau forward. Analyses of GLP-1 trials suggest lean tissue can make up anywhere from around a quarter to more than 40% of total weight lost when nothing is done to protect it — and case reports of patients who trained with resistance work several days a week and ate 0.7–1.7 g of protein per kg daily show lean tissue being largely held, or even gained, during substantial fat loss.
The practical version: aim for protein at every meal — a common target during active weight loss is 1.2 to 1.6 g per kg of body weight a day — and add resistance training two or three times a week, even if that means bands at home or bodyweight squats off a chair. Our guide to eating on Mounjaro or Wegovy covers how to hit those numbers on a genuinely small appetite, and our health advice pages cover fibre, fluid and activity.
Sometimes — but it is the last question, not the first. Mounjaro starts at 2.5 mg and can be increased in 2.5 mg steps after a minimum of four weeks on the current dose, with licensed maintenance doses of 5, 10 and 15 mg. Wegovy escalates over roughly 16 weeks to 2.4 mg weekly, and a 7.2 mg high dose is now available for people who need a higher ceiling. The Wegovy pill steps up to 25 mg daily.
A higher dose usually means more side effects and a higher price, so it should buy you something real. If side effects are what's holding you at a lower dose, our week-by-week side-effect guide is the better place to start — and some people do better staying longer at a smaller step, which we cover on our microdosing page.
Dose increases cost money, and you deserve to see that clearly before deciding. At WeightGone UK, Mounjaro runs from £160/month at 2.5 mg to £190 at 5 mg, £250 at 7.5 mg and £300 at 15 mg. Wegovy runs from £100/month at 0.25 mg to £225 at 2.4 mg, with the 7.2 mg high dose at £250. Every price includes a face-to-face review with a pharmacist each month. Full pricing is on our treatments page, and if you are weighing up a change of medicine entirely, our which treatment guide and switching guide set out how that works.
Paying £60 more a month to break a stall that was actually caused by late doses is money wasted. Fix the free things first.
There is a version of this where the plateau is good news. If you have reached a weight that is healthier and sustainable for you, staying there is the treatment working. Weight regain after stopping is well documented: in SURMOUNT-4, participants reached about 20.9% weight loss over 36 weeks, and those who continued tirzepatide lost a further 5.5% over the next year while those switched to placebo regained 14% — ending at 25.3% versus 9.9% below their starting weight. Semaglutide's STEP 4 trial found the same pattern: continuing gave a further 7.9% loss, stopping gave a 6.9% regain.
UK prescribing guidance for semaglutide asks for a decision point if someone has not lost at least 5% of their starting body weight after six months of treatment. That is a review, not an automatic stop — and it is a different situation entirely from someone who has lost 18% and is holding steady. If you are weighing up stopping altogether, our full guide on coming off treatment without regaining covers the evidence and how to taper safely.
WeightGone UK is a GPhC-registered pharmacy (reg. 1118728) at 250 Stockport Road, Timperley, Altrincham, serving Sale, Hale, Brooklands, Stretford, Wythenshawe and the wider Greater Manchester area. A plateau is exactly the problem that online-only providers handle badly: an app cannot weigh you on the same scales, measure your waist, look at your injection sites or notice that you have started a new medicine that causes weight gain. Every patient here is reviewed face-to-face at least once a month by the same pharmacist, which is how stalls get spotted early and solved cheaply. Not sure whether treatment is right for you at all? Start with our suitability checker or the weight-loss calculator.
Sources
Published 17 August 2026. Written and clinically reviewed by the WeightGone UK pharmacy team. This article is information, not a prescription — suitability, dose changes and any decision to stop treatment are always confirmed face-to-face with a GPhC-registered pharmacist. Trial results are averages and individual results vary.
Usually because your body needs fewer calories now than it did at your starting weight, so the deficit that used to work has quietly closed. A smaller body burns less energy at rest and in movement, and research shows total energy expenditure falls by roughly 15% after a 10% weight loss — more than body size alone explains. Add a partial return of appetite, a few extra portions, or a dose that hasn't kept pace, and the scales settle. It is physiology, not failure, and it is almost always fixable.
A genuine stall of two to three weeks is normal and often resolves on its own, especially around a dose step or a change in routine. If the scales haven't moved for four to six weeks despite consistent dosing, food and activity, that's the point to review it properly with your pharmacist rather than wait it out. A true end-point plateau — where your body has settled at a new stable weight — tends to appear much later, typically after a year or more of treatment.
In the trials, weight settled far later than most people expect. Semaglutide 2.4 mg reached its lowest point around week 60 of a 68-week study, and tirzepatide participants reached or approached a plateau at 72 weeks — with the 5 mg group flattening first and the 10 mg and 15 mg groups still edging down. So a stall at month three or four is very unlikely to be your real ceiling.
Sometimes, but it should never be the automatic first move. Mounjaro can be increased in 2.5 mg steps after a minimum of four weeks, up to 15 mg, and Wegovy escalates to 2.4 mg with a 7.2 mg high dose now available. A dose increase is sensible if you are tolerating your current dose well, your appetite suppression has clearly faded, and the basics are already in place. It is the wrong answer if you are skipping doses, under-eating protein, or the pen has been stored badly.
It contributes. Muscle is metabolically active tissue, so losing it lowers the calories you burn at rest and makes the next kilogram harder. Studies of GLP-1 treatment suggest lean tissue can account for roughly a quarter to more than 40% of total weight lost when nothing is done to protect it. Prioritising protein — commonly 1.2 to 1.6 g per kg of body weight a day — and resistance training two or three times a week is the practical defence.
Rarely. Body weight is a noisy measurement — fluid shifts, a higher-salt weekend, constipation, hormonal cycles and new muscle can all mask genuine fat loss for weeks. Before concluding anything, check waist measurement, how clothes fit, blood pressure and blood results. If your waist is still shrinking while the scales sit still, the treatment is working; the number is just lagging.
Book a review. At our Timperley pharmacy we go through the last month honestly — every missed or late dose, how the pen has been stored, what a typical day of eating looks like, alcohol, sleep, activity and any new medicines that cause weight gain. Most stalls trace back to one or two fixable things. If everything checks out and appetite suppression has genuinely faded, a dose increase or a change of medicine is discussed then.
For most people, yes — maintenance is the point of the treatment, not a consolation prize. In the SURMOUNT-4 trial, people who reached about 20.9% weight loss and then continued tirzepatide lost a further 5.5% over the next year, while those switched to placebo regained 14%. Stopping is a decision to plan with a pharmacist, not something to drift into because the scales have paused.
Medically reviewed by Muhammad Adnan, GPhC-registered Superintendent Pharmacist · Last updated June 2026.
This article is general information and isn't a substitute for personal medical advice. Your pharmacist will assess what's right for you at a face-to-face consultation. More health advice · Book a consultation.
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