If your Mounjaro weight loss stalled around the six-month mark, the data says that is the expected scenario rather than the exception: the median plateau falls between 24 and 36 weeks (Horn et al., Clinical Obesity, 2025). The real-world average at six months is 10.1% of starting body weight — roughly 18 to 24 lb (8 to 11 kg) depending on where you started — not the 14% figure that comes from the clinical trials (Rodriguez et al., JAMA Internal Medicine, 2024, in 18,386 matched patients). One note before we go further: Mounjaro and Zepbound are the same molecule, tirzepatide, sold under two brand names for two different approved uses. Everything below applies to both. This article gives you an honest benchmark, explains why the curve slows exactly now, and ends with three questions to bring to your doctor.
Why has your Mounjaro weight loss stalled at 6 months?
Because six months sits close to the statistical middle of the plateau window. Horn et al. place the median plateau — the point at which weight loss durably flattens — between 24 and 36 weeks depending on starting BMI, which is 5.5 to 8 months. At six months you are not before the plateau; you are inside it.
That reframing matters more than any single number in this article. Watching the scale slow at exactly this point is not evidence of a personal failure or of Mounjaro wearing off. It is the ordinary course of treatment as the research describes it. To see where your own starting BMI puts you in that 24-to-36-week window, you can check your BMI and weight-loss projection first.
What the average Mounjaro result actually is at six months
The honest benchmark is 10.1% of starting body weight at six months, about 20 lb (9 kg) for someone starting at 198 lb (90 kg). This comes from a real-world study — an analysis of the records of patients treated in ordinary clinical practice — rather than from a trial. It is lower than the trial figure, and the gap is largely explained by the Mounjaro dose reached.
One methodological point that changes how you should read it: these figures are on-treatment. They measure patients who were still taking Mounjaro at the time of measurement and do not include those who stopped along the way. That is what makes them interpretable, and also why they do not describe everyone’s path.
| Time point | Average weight loss on Mounjaro (real-world, on-treatment) |
|---|---|
| 3 months | −5.9% |
| 6 months | −10.1% |
| 12 months | −15.3% |
Source: Rodriguez et al., JAMA Internal Medicine, 2024, n = 18,386 matched patients. Percentages stay abstract, so here is the same figure applied to different starting weights.
| Starting weight | Average loss at 6 months |
|---|---|
| 176 lb (80 kg) | about 18 lb (8 kg) |
| 198 lb (90 kg) | about 20 lb (9 kg) |
| 220 lb (100 kg) | about 22 lb (10 kg) |
| 243 lb (110 kg) | about 24 lb (11 kg) |
How many people reach 10% or 15%?
A study published in the Journal of Endocrinological Investigation in 2025, in patients without diabetes treated with Zepbound, found an average loss of 11.15% at six months. In that population, 59% reached at least 10% weight loss and 31.2% reached at least 15%.
The other side of those numbers is what you probably need to hear: roughly 4 in 10 patients do not reach 10% at six months, and 7 in 10 do not reach 15%. That is not an anomaly. It is the normal spread of a treatment for which usually only the average gets published.
Why your number is lower than the trial figure
In SURMOUNT-1, published in the New England Journal of Medicine, weight loss reaches about 14% at 24 weeks, with the nearest published data point being −12.5% at week 20 (the European Medicines Agency EPAR for Mounjaro and FDA documentation). Against 10.1% in the real world at the same horizon: a gap of roughly 4 percentage points. That gap is not biological. It is about dose.
| Clinical trial (SURMOUNT-1) | Real world (Rodriguez et al.) | |
|---|---|---|
| Time point | 24 weeks | 6 months |
| Average loss | about −14% | −10.1% |
| Mounjaro dose | titrated per protocol toward 10 or 15 mg | 42.4% of patients at 10 mg or above |
| Population | selected, closely monitored | patients in ordinary clinical practice |
Why the Mounjaro curve slows down
Weight loss on Mounjaro is not linear; it is front-loaded. The monthly rate is highest in the first three months and then falls steadily. In the second half of the year it runs at just 44% of the initial rate. The slowdown is the shape of the curve, not a sign that something has broken.
| Period | Percentage points gained | Average monthly rate |
|---|---|---|
| Months 0 to 3 | 5.9 points | about 1.97 points per month |
| Months 3 to 6 | 4.2 points | about 1.40 points per month |
| Months 6 to 12 | 5.2 points | about 0.87 points per month |
These rates are derived from the Rodriguez et al. trajectory above. At six months you are at 10.1% of the 15.3% the full year produces, which means 66% of the twelve-month result is already banked. That is what the scale does not tell you. Tracking your weekly rate — which genuinely has halved — measures the speed of your curve instead of its total, and the total is ahead of any linear projection you made in month one.
Honesty has to cut both ways. If two thirds are done, that leaves about 5 points across the next six months, not 10. Anyone projecting linearly gets it wrong twice: first by feeling behind at six months, then by overestimating what the second half will deliver.
Telling a plateau apart from a genuine stop
Several things help you describe the situation to your doctor, though none of them settles it alone: how long the stall has actually lasted, the Mounjaro dose you have reached, how well you tolerate the drug, and how measures other than the scale are moving — waist circumference, how clothes fit, day-to-day energy. The exit from this section is an appointment, not a decision made alone in front of an article.
The Mounjaro dose question: the first suspect
Before concluding that the molecule does not work for you, the first question to ask is about dose. In real-world use, only 42.4% of patients had reached 10 mg or more by six months. Close to six in ten are therefore still below the dose that produced the published figures.
If you compare yourself to an average generated at 10 or 15 mg while you are at 5 mg, you are not comparing like with like. Titration — the gradual dose increase over successive weeks — is part of the treatment, and where yours stopped is first-order information for interpreting your curve. This is something to raise at your next appointment; it is in no way a reason to change a dose on your own.
Why titration stalls outside of trials
Several factors are involved, and they cannot be ranked because their weight varies a great deal by country: gastrointestinal tolerability, which keeps people at a given dose for longer; supply shortages, which sometimes force a step back; cost, when the treatment is not covered — you can compare Mounjaro prices and coverage dose by dose; and the interval between follow-up appointments, which determines when the dose can be reassessed.
Three questions to bring to your appointment.
- What Mounjaro dose am I on today, and for how long have I been on it?
- Is it expected to increase, and on what schedule?
- Does what I am seeing on the scale match what is expected at this stage?
Type 2 diabetes: a different trajectory
If you live with type 2 diabetes, the figures above do not describe your situation. Weight loss on Mounjaro depends heavily on baseline HbA1c — glycated haemoglobin, the marker that reflects blood sugar control over the previous three months. Available data show −17.7% when baseline HbA1c is below 7% and −9.0% when it is 9% or higher. Close to a twofold difference.
Someone with poorly controlled diabetes who compares themselves to the published weight-loss figures is comparing themselves to a population that is not their own. This recalibration is rarely written down, and it prevents a disappointment that has no reason to exist.
Key takeaways
- The real-world Mounjaro benchmark at six months is −10.1%, about 18 to 24 lb (8 to 11 kg) depending on starting weight (Rodriguez et al., JAMA Intern Med 2024, n = 18,386 matched, on-treatment analysis).
- The median plateau falls between 24 and 36 weeks depending on starting BMI (Horn et al., Clinical Obesity 2025). At six months you are inside that window, not ahead of it.
- The monthly rate drops from about 1.97 points in the first quarter to about 0.87 in the second half of the year, or 44% of the initial rate. Weight loss on Mounjaro is front-loaded.
- At six months, 66% of the twelve-month result is already banked — and about 5 points remain for the next six months, not 10.
- On Zepbound without diabetes, 59% exceed 10% weight loss at six months and 31.2% exceed 15%, meaning roughly 4 in 10 do not reach 10% and that is not an anomaly (Journal of Endocrinological Investigation, 2025).
- Only 42.4% of patients had reached 10 mg or more at six months in real-world use, against protocol titration toward 10 or 15 mg in trials. That is the leading explanation for the roughly 4-point gap with SURMOUNT-1.
Frequently asked questions
Why has my Mounjaro weight loss stalled at 6 months?
Because six months sits inside the window where a plateau is statistically expected: the median falls between 24 and 36 weeks depending on starting BMI (Horn et al., Clinical Obesity, 2025). The average monthly rate also drops from about 1.97 percentage points in the first three months to about 0.87 in the second half of the year. A stall at this point is the common course, not a sign the drug has stopped working.
What is the average weight loss on Zepbound at 6 months?
11.15% in patients without diabetes, with 59% reaching at least 10% and 31.2% reaching at least 15% (Journal of Endocrinological Investigation, 2025). Across a broader real-world population on Mounjaro or Zepbound, the average at six months is 10.1% (Rodriguez et al., JAMA Internal Medicine, 2024). Both are population averages, not individual guarantees.
Why did I lose less than the numbers I read about?
The Mounjaro dose is the first thing to look at. In real-world use only 42.4% of patients had reached 10 mg or more by six months, while trials titrate per protocol toward 10 or 15 mg. The gap between SURMOUNT-1 (about −14% at 24 weeks) and real-world data (−10.1%) is roughly 4 percentage points, and dose explains much of it. This is a question for your doctor, not a reason to adjust anything yourself.
Should I stop treatment when the scale stops moving?
That decision belongs with your doctor. What the data show is that a stall at six months arrives while roughly 5 percentage points of loss still lie ahead over the following six months, and often before the trial dose has been reached. Stopping at that exact point therefore often means ending a treatment that has not yet delivered its full effect.
Medical disclaimer. This article is strictly informational and does not replace medical advice. The figures cited are population averages drawn from published studies and do not predict your individual result. Nothing in this article constitutes a dose recommendation, a titration schedule or a course of action: any decision to start, change, continue or stop a treatment should be made with a healthcare professional. Information current as of 1 August 2026.
To track the effect on your own curve, logged data beats vague recollections on the day of your appointment: the MounjaGO app brings together weight, doses, side effects and meals, and turns them into a PDF report for your doctor — $12 for lifetime access, no subscription.