Weight Loss Timeline
See how weight loss typically progresses on Mounjaro and Wegovy, from early appetite changes to longer-term results.
Whether you are tracking your own progress or planning ahead before starting, this is a calendar-style weight-loss timeline for Mounjaro and Wegovy — a quick-reference page covering what to expect at each milestone, with the underlying clinical-trial figures alongside. For the narrative explainer, see our when do you see results guide; this page is for the at-a-glance view. LetsLoseWeight is an independent comparison site; we do not prescribe medication. Individual timelines vary.
At-a-glance: average trial timeline
The figures below come from the SURMOUNT-1 trial for tirzepatide and the STEP 1 trial for semaglutide 2.4mg. Cumulative average weight loss as a percentage of starting weight:
| Time point | Mounjaro 15mg | Mounjaro 10mg | Mounjaro 5mg | Wegovy 2.4mg |
|---|---|---|---|---|
| Week 4 | ~1–2% | ~1–2% | ~1–2% | ~1–2% |
| Week 12 | ~6–8% | ~6–8% | ~5–6% | ~5–6% |
| Week 24 (6 months) | ~13–15% | ~12–14% | ~10–11% | ~10–12% |
| Week 36 (9 months) | ~17–19% | ~15–17% | ~12–13% | ~13–14% |
| Week 52 (12 months) | ~19–21% | ~18–19% | ~13–15% | ~14–15% |
| Week 72 (~17 months) | ~20.9% | ~19.5% | ~15.0% | (trial ended week 68) |
| Week 68 (~16 months) | — | — | — | ~14.9% |
These are averages from clinical trials — your individual results will vary based on adherence, lifestyle, dose, and individual response.
Translating percentages to weight
For a starting weight of 100kg, the percentages above translate to roughly:
| Time point | Mounjaro 15mg | Wegovy 2.4mg |
|---|---|---|
| Week 4 | ~1–2 kg | ~1–2 kg |
| Week 12 | ~6–8 kg | ~5–6 kg |
| Week 24 | ~13–15 kg | ~10–12 kg |
| Week 52 | ~19–21 kg | ~14–15 kg |
| End of trial | ~21 kg | ~15 kg |
For other starting weights, multiply your weight by the percentage (e.g. 90kg starting weight × 20% = 18kg average loss).
Milestone-by-milestone
Day 1: First injection
The starter dose (2.5mg Mounjaro / 0.25mg Wegovy) is below the threshold for full clinical effect — it is there to let the body adjust. Some people notice mild side effects (nausea, slight stomach upset) within 24–48 hours.
Week 1: Appetite changes
Most patients notice reduced appetite within 5–10 days. "Food noise" quietens, smaller portions feel satisfying, and there is less interest in fatty or sugary foods specifically.
Week 2: Side effects settle
If side effects appeared in week 1, they often settle by week 2 as the body adjusts. Weight may begin to drop, but not always at this dose.
Week 4: First dose increase due
End of the starter month. Average weight loss by this point is around 1–2% of starting weight. The dose typically steps up to 5mg Mounjaro or 0.5mg Wegovy at the start of week 5.
Week 8: First clinically meaningful loss
Average weight loss by week 8 is around 3–5% of starting weight. The 5% threshold often marks where weight-related health markers begin to improve.
Week 12 (3 months): Settling into pattern
Average weight loss around 5–8%. Most patients are at 7.5mg Mounjaro or 1mg Wegovy. Non-scale changes — clothes fitting, easier movement, better sleep — often become noticeable.
Week 16 (4 months): Wegovy maintenance dose reached
Wegovy patients reach the full 2.4mg maintenance dose around week 17 (after the 16-week titration). Mounjaro patients are still mid-titration, often at 10mg.
Week 24 (6 months): Steady loss phase
Average weight loss for Wegovy: ~10–12%. For Mounjaro at 10mg: ~12–14%. Most Mounjaro patients are at maintenance dose (5mg, 10mg, or 15mg) by this point.
Week 36 (9 months): Most weight already lost
By 9 months, most patients have achieved the majority of their eventual weight loss. The remaining 3–6 months tend to be slower, smaller losses.
Week 52 (12 months): Approaching plateau
Weight loss begins to slow. Most patients are within a few percentage points of their final trial-reported plateau.
Week 68–72 (16–18 months): Trial endpoint
End of the published trials. Average weight loss reaches its measured maximum:
- Mounjaro 15mg: ~20.9%
- Mounjaro 10mg: ~19.5%
- Mounjaro 5mg: ~15.0%
- Wegovy 2.4mg: ~14.9%
Beyond 18 months: Maintenance
Most patients have reached their personal plateau. The medicine's role shifts from weight reduction to weight maintenance against the body's natural tendency to regain.
Stopping: Regain phase
If the medicine is stopped, weight regain is common. The STEP 1 extension trial showed average regain of around two-thirds of lost weight within 12 months of stopping (Wilding et al., 2022). Lifestyle changes maintained alongside the medicine help reduce this.
Personal timeline tracker
To track your own progress against the trial averages:
- Note your starting weight on day 1
- Calculate the trial-average target for each milestone using the percentage tables above
- Weigh in at the same time of day, 1–2 times per week
- Compare your trajectory to the averages, but don't expect to track them exactly
A simple way to set personal expectations: at 12 weeks, look for around 5–8% loss; at 6 months, around 10–14%; at 12 months, somewhere around 15–20% if on Mounjaro at higher doses, or 12–15% on Wegovy.
If you are significantly below these by 6 months, talk to your prescriber about whether dose adjustment or switching medicine is appropriate.
What slows the timeline
Common reasons your trajectory might be slower than trial averages:
- Below maintenance dose — titrating slowly extends the timeline.
- Inconsistent dosing — missed weeks reset some of the medicine's effect.
- Calorie creep — appetite reduction does not force a deficit if higher-calorie food is on the menu.
- Sleep deprivation — disrupts appetite hormones independently of the medicine.
- Other medications — antidepressants, antipsychotics, steroids and some contraceptives can blunt weight effects.
- Slow metabolism baseline — individual variation is real and not necessarily fixable.
For more, see our what affects results guide.
What accelerates the timeline
Some patterns tend to produce faster-than-average weight loss:
- Larger starting weight — heavier patients lose more in absolute terms in the first months.
- Combined dietary intervention — a structured calorie-reduced diet on top of the medicine.
- Resistance training — preserves muscle and supports metabolic health.
- Low alcohol intake — alcohol is calorie-dense and can blunt fullness signalling.
- Adequate sleep — supports the hormonal effects of the medicine.
These do not change the eventual plateau much for most patients, but they shift when the plateau is reached.
Frequently asked questions
Should I expect to lose 1kg per week?
Trial averages work out to around 0.5–1% of starting weight per week during the active loss phase — for a 100kg starting weight, that is 0.5–1kg per week. Faster than 1% per week is uncommon and not necessarily desirable; rapid loss tends to drive worse side effects and more muscle loss.
What if I haven't lost anything by week 4?
Some patients lose very little at the starter dose. The first dose increase at week 5 usually accelerates loss. If you are still seeing no change by week 8 at the higher dose, talk to your prescriber.
Why does the weight come off slower in month 6 than in month 2?
Several reasons: smaller body weight produces a smaller calorie deficit at the same intake; metabolic adaptation slows the rate of loss; appetite tends to recover slightly with longer treatment. The slowing is normal and expected.
Is the timeline different for type 2 diabetes?
Yes — patients with type 2 diabetes generally lose less weight on average than patients without diabetes, on the same medicine and dose. Diabetes affects insulin sensitivity and metabolic responsiveness in ways that reduce the rate of weight loss.
Next steps
- Narrative explainer: When do you see results
- Total expectations: How much weight can you lose
- Per-medicine results: Mounjaro results · Wegovy results
- Hit a plateau? Plateau and not losing weight
Sources
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). New England Journal of Medicine. 2022;387(3):205–216. https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
- Wilding JPH, Batterham RL, Calanna S, et al.; STEP 1 Study Group. Once-weekly semaglutide in adults with overweight or obesity. New England Journal of Medicine. 2021;384(11):989–1002. https://www.nejm.org/doi/full/10.1056/NEJMoa2032183
- Wilding JPH, Batterham RL, Davies M, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide. Diabetes, Obesity and Metabolism. 2022;24:1553–1564. https://dom-pubs.onlinelibrary.wiley.com/doi/10.1111/dom.14725
This guide is for general information only and is not a substitute for professional medical advice. Trial averages do not predict individual results.
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