Mounjaro v Wegovy: What Are the Differences?

The most important distinction between Mounjaro and Wegovy lies in their active substances and how they act on the body.

Active substances and mechanism

• Wegovy contains semaglutide, a GLP-1 receptor agonist. It mimics the GLP-1 hormone, which plays a role in regulating appetite and feelings of fullness, and slows gastric emptying — an effect that often reduces over time.
• Mounjaro contains tirzepatide, a dual GIP and GLP-1 receptor agonist. It acts on both the GIP and GLP-1 pathways. Both hormones are involved in appetite regulation and metabolic responses.

Dose strengths

Wegovy is commonly prescribed at dose strengths of 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, and 2.4 mg. Mounjaro is commonly available at 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg. Both are typically started at a lower dose and adjusted over time — always under the direction of a prescriber. For a closer look at how these two medicines compare side by side, see our detailed Mounjaro vs Wegovy comparison.

Delivery and monitoring

Both medicines are supplied as pre-filled injectable pens administered once a week. Both carry a Black Triangle (▼) designation in the UK, meaning they are subject to additional monitoring. Any suspected side effects should be reported to your healthcare professional and, if you are in the UK, through the Yellow Card scheme — or through your own country's equivalent national reporting scheme.

What they share

Despite these differences, Mounjaro and Wegovy share a great deal in common: both are prescription-only, both are unsuitable for everyone (your prescriber determines suitability), and neither is a standalone solution — diet, physical activity, and clinical supervision all remain part of the picture. You can read more about Wegovy (semaglutide) or explore the full Mounjaro guide for deeper background on each medicine. If you are wondering how doses across the two medicines relate to one another, understanding Mounjaro and Wegovy equivalent doses may also be useful context.

A note on cost

The cost of these medicines varies by country, healthcare system, and how a prescription is obtained. No figures are given here because they differ widely and change over time — your prescriber, pharmacist, or healthcare provider is the right source for current cost information relevant to your situation.

GLP Trackr is built for people already prescribed either Mounjaro or Wegovy — the app supports both medicines fully, so whichever pen you are injecting, your tracking experience is the same.

The most relevant feature when navigating two medicines that share a weekly injection schedule is dose and injection logging. Every shot is recorded with the dose strength, date, time, and injection site, giving you a clear, timestamped history you can bring to prescriber appointments. If you are mid-titration or your prescriber has recently adjusted your dose, having that log means nothing falls through the gaps.

Beyond dose tracking, the side-effect logger lets you record how you feel after each injection — useful when comparing your own experience across dose changes — and the insights tools surface patterns in your data over time, including correlations between how you feel, what you eat, and how your weight is moving.

Any decision about which medicine is right for you, or any change to your dose or prescription, belongs with your prescriber or doctor — GLP Trackr supports the journey you are already on, it does not guide clinical choices.

Whether you are on Mounjaro or Wegovy, keeping your tracking consistent is one of the most practical things you can do to stay on top of your journey. GLP Trackr is free to try for 7 days — download it on the App Store or Google Play and start logging from your very next dose.