Switching from Mounjaro to Wegovy: What to Know

Mounjaro contains tirzepatide, a dual GIP and GLP-1 receptor agonist, while Wegovy contains semaglutide, which acts on GLP-1 receptors only. Because these two medicines work through overlapping but not identical pathways, switching between them is not simply a like-for-like swap — your prescriber will determine whether a switch is appropriate, which dose to start on, and how the transition should be managed for your individual circumstances.

Side effects you may notice after switching

Many of the commonly reported side effects are similar across both medicines — nausea, changes in bowel habits, fatigue, and indigestion are frequently described with both tirzepatide and semaglutide. However, because Wegovy uses a different active substance, some people notice that side effects they had settled into on Mounjaro feel more prominent again after switching, particularly in the first few weeks. This is not unusual when any GLP-1 medicine dose or type changes, but it is worth logging carefully so you can discuss it with your prescriber.

A note on dose equivalence

A common question is whether you can go straight from one dose of Mounjaro to a comparable dose of Wegovy — for example, whether someone on 2.5 mg tirzepatide can move directly to a mid-range semaglutide dose. There is no straightforward conversion between the two medicines' dose scales, and any starting dose on Wegovy should be decided by your prescriber based on your history. For more detail on how dosing works after a switch, see how dosing is managed when moving between these medicines.

Is switching common?

People switch for a variety of reasons — availability, tolerability, prescriber preference, or a change in clinical circumstances. Whether it is appropriate for you is something only your prescriber can assess with full knowledge of your health history. For a broader look at the practical and clinical considerations, the pages on switching between these GLP-1 medicines and whether switching is suitable for you cover this in more detail. Both medicines are prescription-only, and suitability is always an individual decision.

A medicine switch is exactly the kind of moment where having a clear record of how you feel day to day becomes genuinely useful. GLP Trackr's side-effect tracker lets you log symptoms — nausea, fatigue, digestive changes, injection-site reactions — and view them over time, so you can see whether things are settling or getting worse. That pattern data is something concrete to bring to your next prescriber appointment rather than relying on memory.

Alongside side-effect logging, the dose logging feature means every injection is recorded with its date, dose strength, and site — so if your prescriber adjusts your Wegovy starting dose in the first weeks, you have an accurate timeline of exactly what you took and when. This kind of record is particularly helpful during a transition period when your routine is changing.

You can find general information about commonly reported experiences across both medicines in the Mounjaro side effects guide, which gives useful context for what you may have experienced before your switch.

Important: if you notice side effects that are severe, persistent, or feel different from anything you experienced on Mounjaro — particularly anything affecting your abdomen, heart rate, or mood — contact your healthcare professional promptly. GLP Trackr helps you record what you are experiencing so you can have an informed conversation with your prescriber; it is not a substitute for their clinical judgement. Any concerns about whether the switch is right for you should always go back to the person who prescribed the medicine.

Ready to keep a clear record of your transition? Download GLP Trackr on the App Store or Google Play and start a free 7-day trial — log your side effects, doses, and how you feel each day, all in one place.