Mounjaro vs Wegovy: What's the Difference?

The most meaningful clinical difference lies in how each medicine works at a receptor level.

Active substance and mechanism

• Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist. It acts on two appetite-regulating pathways simultaneously — the glucose-dependent insulinotropic polypeptide (GIP) pathway and the glucagon-like peptide-1 (GLP-1) pathway.
• Wegovy (semaglutide) is a GLP-1 receptor agonist, acting on the GLP-1 pathway alone.

Both medicines are commonly described as reducing appetite and increasing feelings of fullness, partly through slowing gastric emptying — an effect that often reduces over time. These are shared features of GLP-1 receptor agonism; the additional GIP activity in tirzepatide is what distinguishes it mechanically, though what that difference means for any individual person is something to discuss with your prescriber.

Dose strengths

• Mounjaro is typically started at a low dose (commonly 2.5 mg) and adjusted upward over time by the prescriber, with available strengths including 2.5, 5, 7.5, 10, 12.5, and 15 mg.
• Wegovy follows a similar titration approach, with commonly referenced strengths of 0.25, 0.5, 1, 1.7, and 2.4 mg.

In both cases, dose progression is decided by your prescriber — not by the patient alone. Both medicines are supplied as pre-filled injection pens and administered once weekly, typically into the abdomen, thigh, or upper arm.

Monitoring status

Both medicines carry additional monitoring status (indicated by a black triangle ▼ in the UK). Any suspected side effects should be reported to your healthcare professional and to your national reporting scheme — such as the UK's Yellow Card scheme — or its equivalent in your country. For a fuller side-by-side look at how side effects compare, see how the side-effect profiles of Mounjaro and Wegovy compare.

For a broader overview of the two medicines together, the Wegovy vs Mounjaro comparison hub covers the topic in more depth. You may also find it useful to read about how Ozempic and Wegovy differ, since semaglutide appears in both under different licensed indications.

GLP Trackr is built to support people on both Mounjaro and Wegovy — the app doesn't favour one medicine over the other, because that decision belongs entirely with your prescriber.

The feature that tends to matter most when you're getting started is dose and injection logging. Because both medicines follow a titration schedule — starting low and adjusting over time — keeping a clear record of each dose, its strength, the date, and the injection site helps you stay on top of where you are in your programme. GLP Trackr logs all of this automatically and tracks injection-site rotation, suggesting your next site so you don't have to remember manually.

If you're noticing side effects — nausea, fatigue, digestive changes, or anything else — the side-effect tracker lets you log symptoms as they happen and see patterns over time. That log can be genuinely useful to bring to your next prescriber appointment, especially if you're navigating a dose increase on either medicine.

Whether you're on tirzepatide or semaglutide, the fundamentals of tracking your journey are the same: doses, food, weight, and how you feel. GLP Trackr brings all of that together in one place.

A note on the comparison itself: if you're wondering which of these medicines is right for you, or whether switching might make sense, that conversation belongs with your prescriber or doctor — they know your full medical history and are best placed to guide you. GLP Trackr is a tracking companion, not a clinical adviser.

Ready to keep a clear record of your journey? GLP Trackr is free to try for 7 days — available on the App Store and Google Play. Log your doses, track how you feel, and bring better information to your prescriber appointments. Also see the full Mounjaro vs Wegovy comparison for more detail on both medicines.