Weight and plateaus
Mounjaro Weight Loss by Month in the Trials, in Kg and Stone
Mounjaro weight loss by month in SURMOUNT-1: 62.1% had lost 5% or more by week 8, and the 15 mg group averaged 20.9% at week 72.
Medically reviewed by Farnia Bahari, PharmD
Published 9 min read
Mounjaro weight loss by month is printed in the trials at weeks 8, 20, 36 and 72, not for every month. By week 8, after 4 weeks on the 2.5 mg starting dose and 4 weeks on 5 mg (SmPC, section 4.2), 62.1% of the 1,775 people on tirzepatide in SURMOUNT-1 had lost at least 5% (early-response analysis). By week 72, average losses were 15.0% on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg, against 3.1% on placebo (SURMOUNT-1).
Key facts
- Month 1 is 2.5 mg; further 2.5 mg steps need at least 4 weeks per dose, and adult maintenance doses are 5 mg, 10 mg and 15 mg (SmPC, section 4.2).
- By week 8, about 1.8 calendar months in, 62.1% had lost at least 5%, after 4 weeks each on 2.5 mg and 5 mg (early-response analysis).
- People below 5% at week 8 still averaged 14.6% at week 72 using the efficacy estimand, and 87.5% of them reached 5% by week 72 (early-response analysis).
- Week-72 averages were 15.0% on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg, against 3.1% on placebo (SURMOUNT-1).
- The SURMOUNT-4 lead-in average was 20.9% at week 36 among the 670 people still on treatment (SURMOUNT-4).
- NICE calls for a continuation decision if less than 5% has been lost after 6 months on your highest tolerated dose (TA1026 recommendations).
How much weight can you lose on Mounjaro in a month?
SURMOUNT-1 and its early-response analysis print an average at weeks 8, 20 and 72, and SURMOUNT-4 adds week 36. Every other month appears only on the SURMOUNT-1 graph (SURMOUNT-1).
A dose month means 4 weeks here, giving 13 dose months per year under the UK escalation schedule. Those blocks do not line up exactly with calendar months.
The table pairs the UK dose ladder with SURMOUNT-1, its early-response analysis and SURMOUNT-4. Doses show when steps first become possible; results belong to the named trial groups.
| 4-week month and earliest UK dose | Reported weight result | Where it is printed |
|---|---|---|
| Month 1 (weeks 1 to 4), 2.5 mg | No printed average | Graph only (Figure 1) |
| Month 2 (weeks 5 to 8), 5 mg | 62.1% had lost 5% or more; average 7.9% for early responders or 3.1% for the rest | Text |
| Month 3 (weeks 9 to 12), 7.5 mg | No printed average | Graph only (Figure 1) |
| Month 4 (weeks 13 to 16), 10 mg | No printed average | Graph only (Figure 1) |
| Month 5 (weeks 17 to 20), 12.5 mg | Groups assigned to 10 mg and 15 mg, pooled, lost 12.8 kg, about 2 st, against 2.7 kg on placebo | Table 3 |
| Month 6 (weeks 21 to 24), 15 mg | No printed average | Graph only (Figure 1) |
| Ninth dose month, week 36, 10 or 15 mg (SURMOUNT-4) | 20.9% in the 670 still on treatment, open label | Text |
| 18th dose month, week 72, 5, 10 or 15 mg (SURMOUNT-1) | 15.0%, 19.5% or 20.9% by dose, against 3.1% on placebo | Abstract and Table 2 |
The week-20 kilogram result uses the treatment-regimen estimand, counting participants whether or not they continued treatment (SURMOUNT-1).
What dose of Mounjaro are you on each month?
Mounjaro starts at 2.5 mg weekly, increases to 5 mg after 4 weeks, and allows further increases only after at least 4 weeks on the current dose (SmPC, section 4.2).
Further increases are in 2.5 mg steps if needed; the adult maintenance doses are 5 mg, 10 mg and 15 mg (SmPC, section 4.2). Staying at a maintenance dose is therefore part of the labelled schedule.
SURMOUNT-1’s 15 mg group reached 15 mg by week 20, so month 6, weeks 21 to 24, is the earliest month spent fully on that dose (trial methods). The 5 mg and 10 mg groups stopped stepping up when they reached their assigned dose, so the trial’s 10 mg and 15 mg results include the weeks spent on lower doses.
Use the titration planner to put the earliest step dates against your injection dates. A step date shows when an increase becomes possible under the schedule.
If you are moving to Mounjaro after a stall on semaglutide, read switching from Ozempic to Mounjaro after a plateau.
How much weight do you lose in the first month on Mounjaro?
SURMOUNT-1 prints no average for the first 4 weeks on Mounjaro; its graph shows that point (SURMOUNT-1). The first printed number comes at week 8, when 62.1% had lost at least 5% (early-response analysis).
Your first month on Mounjaro is on the 2.5 mg starting dose, with an increase to 5 mg after 4 weeks under the UK label (SmPC, section 4.2).
Every SURMOUNT-1 group started on 2.5 mg, so the trial has one first-month curve, not one per dose (SURMOUNT-1 methods). The trial’s 15 mg endpoint includes that same starting period.
Check when Mounjaro starts working on appetite if you are comparing hunger changes with your first-month weigh-ins.
Why is there no weight loss in my first month on Mounjaro?
The SURMOUNT-1 early-response analysis grouped people by whether they had lost at least 5% by week 8, and 37.9% had not (early-response analysis).
Those who had, the early responders, averaged 7.9% at week 8, against 3.1% for the rest (early-response analysis). Everyone had taken 2.5 mg for 4 weeks and then 5 mg for 4 weeks.
By week 72, the early responders averaged 23.3% loss and the slower group averaged 14.6% (early-response analysis). These results use the efficacy estimand, which uses weights recorded while people were still on treatment.
Among people who had not reached 5% loss by week 8, 87.5% reached that threshold by week 72 (early-response analysis). From a 105 kg start, the slower group’s 14.6% is 15.3 kg, or 2 st 6 lb.
Compare your own weigh-ins at the same time on treatment, with the dose you were on. If hunger returns after your increase, check food noise on Mounjaro 5 mg.
What are typical Mounjaro results after 3 months?
SURMOUNT-1 prints no 3-month Mounjaro average; week 12 appears only on its graph (SURMOUNT-1). Three calendar months is about 13 weeks, and the printed points either side are week 8 and week 20 (early-response analysis).
At week 8, 62.1% had lost at least 5%; average losses were 7.9% for early responders and 3.1% for the rest (early-response analysis).
The nearest printed kilogram result is 12.8 kg, about 2 st, at week 20, about 4.6 calendar months, in the pooled 10 mg and 15 mg groups (SURMOUNT-1).
On the earliest UK schedule, weeks 9 to 12 are on 7.5 mg and weeks 13 to 16 on 10 mg (SmPC, section 4.2).
Among slower starters below 5% at week 8, 87.5% had reached that threshold by week 72 (early-response analysis).
How much weight can you lose on Mounjaro in 6 months?
SURMOUNT-1 prints no 6-month Mounjaro average; week 24 appears only on its graph (SURMOUNT-1). Six calendar months is about 26 weeks.
The week-20 average was 12.8 kg in the pooled 10 mg and 15 mg groups, against 2.7 kg on placebo (SURMOUNT-1).
SURMOUNT-4 reported average loss of 20.9% at week 36, about 8.3 calendar months, among 670 people still on treatment (SURMOUNT-4). Their highest tolerated doses were 10 mg or 15 mg, with 92.7% on 15 mg and 7.3% on 10 mg.
The lead-in was open label, meaning participants knew they were receiving tirzepatide, and 113 people stopped during it (SURMOUNT-4). Its completer average describes a selected group later in treatment. The week-20 and week-36 results come from different trials and groups, so they cannot be averaged into a 6-month figure.
If you lose less than 5% after 6 months on your highest tolerated dose, decide with your prescriber whether to continue, weighing benefits and risks (NICE TA1026). This is not automatic stopping.
The SmPC uses the same checkpoint; from 105 kg, that 5% threshold is 5.3 kg, or 12 lb (SmPC, section 4.2).
How much weight can you lose on Mounjaro in a year?
SURMOUNT-1 prints no 12-month Mounjaro average; its endpoint is week 72, about 16.6 calendar months (SURMOUNT-1).
Average losses were 15.0% on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg, compared with 3.1% on placebo (SURMOUNT-1). These are treatment-regimen estimates, counting participants whether or not they kept taking treatment.
By week 72, 85% on 5 mg, 89% on 10 mg and 91% on 15 mg had lost at least 5% (SURMOUNT-1).
At the endpoint, 50% on 10 mg and 57% on 15 mg had lost at least 20%, compared with 3% on placebo (SURMOUNT-1).
For a 12-month estimate, use the weight loss projector, which fits a curve to the week-72 endpoint; this article shows the observed trial points.
When comparing your result with an endpoint, match the time on treatment before comparing the percentage. SURMOUNT-1’s 72 weeks include the step-up weeks on lower doses (SURMOUNT-1).
For semaglutide’s trial results by week and dose, see the Wegovy results timeline.
What does Mounjaro weight loss look like in kg and stone?
From a 105 kg start, the 20.9% average on 15 mg at week 72 in SURMOUNT-1 equals 21.9 kg, or 3 st 6 lb.
That example starts at 16 st 7 lb, close to the trial’s average starting weight of 104.8 kg (SURMOUNT-1).
The week-72 responder rows use the efficacy estimand; the week-72 dose rows use treatment-regimen estimates (early-response analysis, SURMOUNT-1). The week-36 population is the 670 SURMOUNT-4 lead-in completers (SURMOUNT-4).
The table converts percentages from SURMOUNT-1, its early-response analysis and SURMOUNT-4 into losses from 105 kg. The week-20 row is the trial’s own average in kg, not a calculation from 105 kg.
| Trial point and percentage lost | Loss (kg) | Loss (st and lb) |
|---|---|---|
| Week 8 slower group, 3.1% | 3.3 | 7 lb |
| Week 8 early responders, 7.9% | 8.3 | 1 st 4 lb |
| Week 20, 10 mg and 15 mg groups pooled (trial average in kg, not from 105 kg) | 12.8 | About 2 st |
| Week 36 SURMOUNT-4 completers, 20.9% | 21.9 | 3 st 6 lb |
| Week 72 slower group, 14.6% | 15.3 | 2 st 6 lb |
| Week 72 on 5 mg, 15.0% | 15.8 | 2 st 7 lb |
| Week 72 on 10 mg, 19.5% | 20.5 | 3 st 3 lb |
| Week 72 on 15 mg, 20.9% | 21.9 | 3 st 6 lb |
| Week 72 early responders, 23.3% | 24.5 | 3 st 12 lb |
You can see your own weight line alongside the dose you logged in Pensday. Its free weight report colours each weigh-in by the dose logged that week, so a slow 2.5 mg month sits next to the 5 mg month. Dose logging and dose reminders are free too. With your weights and doses logged, you can read your own week 8 or week 20 against the tables above.
To set a target of your own rather than borrow a trial average, use the goal weight calculator.
For where the weight comes off, see what body scans show on Ozempic and Mounjaro.
Why do online monthly figures for Mounjaro differ?
Apart from the week-8 split in the 2026 early-response analysis, SURMOUNT-1 prints no average percentage for any week before 72, so other monthly percentages credited to it have been read off its graph or estimated (SURMOUNT-1). Figures also differ because they describe different groups and analyses.
The 20.9% figure appears at week 72 for the highest assigned dose in SURMOUNT-1 and at week 36 among SURMOUNT-4 completers (SURMOUNT-1, SURMOUNT-4). The former counts everyone randomised; the latter describes the 670 people still on treatment.
The analysis method also changes the number. On 15 mg, SURMOUNT-1 reported 20.9% using the treatment-regimen estimate and 22.5% using the efficacy estimate (SURMOUNT-1).
Before using a monthly figure as a target, check its week, dose and population. Then check whether it is printed as a number or read off a graph.
Questions
Frequently asked questions
How much weight can you lose on Mounjaro in 2 weeks?
SURMOUNT-1 and its early-response analysis print no average for 2 weeks on Mounjaro (early-response analysis). Their first number is at week 8, when 62.1% had lost at least 5%.
Will I be taken off Mounjaro if I lose less than 5%?
Stopping Mounjaro is not automatic. If you lose less than 5% after 6 months on your highest tolerated dose, decide with your prescriber whether to continue, weighing benefits and risks (NICE TA1026). From 105 kg, that 5% threshold is 5.3 kg, or 12 lb.
Why do Mumsnet and Reddit monthly results look bigger?
A Mounjaro forum post is one person’s result that they chose to share, with no placebo group beside it. In SURMOUNT-1, 57% on 15 mg lost at least 20% by week 72, while 9% did not reach 5% (SURMOUNT-1).
Is weight loss on Mounjaro the same as on Zepbound?
Yes, the medicine is the same. Mounjaro and Zepbound both contain tirzepatide, and SURMOUNT-1 supports both the UK and US labels (Zepbound label). On 15 mg, the week-72 average was 20.9% (SURMOUNT-1).
Sources
- Mounjaro KwikPen: summary of product characteristics. Electronic Medicines Compendium, 2026.
- Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). New England Journal of Medicine, 2022.
- Tirzepatide efficacy and tolerability according to early weight response: a post hoc analysis of the SURMOUNT-1 and SURMOUNT-2 trials. Diabetes, Obesity and Metabolism, 2026.
- Continued treatment with tirzepatide for maintenance of weight reduction in adults with obesity: the SURMOUNT-4 randomized clinical trial. JAMA, 2024.
- Tirzepatide for managing overweight and obesity (TA1026). National Institute for Health and Care Excellence, 2024.
- Zepbound (tirzepatide) prescribing information. DailyMed, 2026.
