Switching Between Mounjaro and Wegovy: Clinical Guidance for Dose Selection
Switching between tirzepatide (Mounjaro) and semaglutide (Wegovy) is a common part of long-term medical weight-management. Patients may change treatment due to availability, tolerability, side-effect profile, or differences in appetite control. While the two medicines act on overlapping incretin pathways, they are pharmacologically distinct and are not directly interchangeable on a milligram-for-milligram basis. For this reason, careful dose selection and gradual titration remain essential when transitioning from one to the other.
In clinical practice, the starting dose of the new medicine is typically informed by the last tolerated dose of the previous agent, alongside the individual’s gastrointestinal tolerance, weight-loss response, and overall clinical picture. A short washout period of around seven days is generally used to reduce overlapping gastrointestinal effects before the new treatment is started.
Switching from Mounjaro to Wegovy
When switching from Mounjaro to Wegovy, semaglutide is introduced at a dose that reflects the patient’s prior exposure to tirzepatide and their demonstrated tolerability. Although both agents slow gastric emptying and suppress appetite, patients often notice that appetite suppression with Wegovy builds more gradually, particularly at lower doses. For this reason, dose selection aims to balance continuity of effect with minimising nausea, reflux, and early satiety.
Recommended starting doses when switching from Mounjaro to Wegovy
| Last tolerated Mounjaro dose | Wegovy starting dose |
|---|---|
| 2.5 mg | 0.25 mg |
| 5 mg | 0.5 mg |
| 7.5 mg | 0.5 mg |
| 10 mg | 1 mg |
| 12.5 mg | 1 mg |
| 15 mg | 1.7 mg |
After initiation, Wegovy can be titrated through the usual dose ladder, progressing to the maintenance dose of 2.4 mg as tolerated. If gastrointestinal symptoms occur, remaining at the current dose for longer than four weeks is often sufficient to restore tolerability.
Switching from Wegovy to Mounjaro
Switching from Wegovy to Mounjaro follows the same principles. Tirzepatide has dual GIP and GLP-1 receptor activity, and some patients experience stronger appetite suppression or more pronounced gastrointestinal effects when first introduced. Selecting an appropriate starting dose based on the last tolerated semaglutide dose helps reduce treatment interruption and avoids unnecessary re-titration from the lowest strength.
Recommended starting doses when switching from Wegovy to Mounjaro
| Last tolerated Wegovy dose | Mounjaro starting dose |
|---|---|
| 0.25 mg | 2.5 mg |
| 0.5 mg | 5 mg |
| 1 mg | 7.5 mg |
| 1.7 mg | 10 mg |
| 2.4 mg | 12.5 mg |
| 7.2 mg | 15 mg |
Once treatment has begun, Mounjaro can be titrated in line with the standard weekly escalation schedule, provided the patient remains comfortable at each step.
What to expect after switching
During the first few weeks after switching, appetite suppression and satiety may feel different compared with the previous medicine. Some patients report milder effects initially, while others notice stronger fullness or earlier satiety. Transient nausea, indigestion, or reflux are common and usually settle with time. Eating smaller meals, slowing eating speed, and maintaining hydration can significantly reduce symptoms.
If side effects persist, extending the time spent at a given dose is often more effective than reducing the dose altogether. Ongoing monitoring ensures the balance between tolerability and weight-loss efficacy is maintained.
Key considerations
Switching between Mounjaro and Wegovy should always be individualised. Dose equivalence tables provide a useful framework, but clinical judgement remains central to safe and effective prescribing. With appropriate dose selection, most patients transition smoothly and continue to achieve meaningful appetite control and weight-loss benefits.
