Wegovy Compared to Mounjaro: What You Need to Know

The most fundamental difference between the two medicines lies in how they act on the body's appetite-regulating pathways.

Active substances and mechanisms

• Wegovy contains semaglutide, a GLP-1 receptor agonist. It mimics a naturally occurring hormone that acts on appetite-regulating centres in the brain, promotes a sense of fullness, and slows the rate at which the stomach empties.
• Mounjaro contains tirzepatide, a dual GIP and GLP-1 receptor agonist. It acts on both of these appetite-regulating pathways simultaneously — a distinction that is factual and structural, not a claim about which medicine is superior.

How they are taken

Both medicines are injected once a week using a pre-filled pen device, typically into the abdomen, thigh, or upper arm. Both are generally started at a lower dose and adjusted over time — always under the guidance of the prescriber. For a closer look at how the dose schedules compare, see how Wegovy doses compare to Mounjaro doses.

Commonly referenced dose strengths

• Wegovy (semaglutide): 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, and 2.4 mg
• Mounjaro (tirzepatide): 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg

Note that the dose numbering systems are not directly comparable between the two medicines — they are different molecules measured differently. For example, if you are curious about how the 1 mg Wegovy dose relates to Mounjaro, that page explores the topic in more detail.

Side-effect profiles

Both medicines share a broadly similar range of commonly reported side effects, largely reflecting their shared GLP-1 activity. These include nausea, vomiting, diarrhoea, constipation, indigestion, and injection-site reactions. Fatigue, headache, and dizziness are also commonly reported. As with any medicine, individual experiences vary — not everyone will experience the same effects, and severity differs from person to person.

Both Wegovy and Mounjaro carry a black triangle (▼) designation in the UK, meaning they are subject to additional monitoring. Side effects should be reported to a healthcare professional and to your national reporting scheme (such as the UK's Yellow Card scheme or the equivalent in your country). You can find further factual information in the electronic Medicines Compendium (eMC), which hosts the official prescribing and patient information for both medicines.

For a broader overview of how these medicines compare across multiple dimensions, visit the Wegovy vs Mounjaro comparison hub.

GLP Trackr is built to support people already taking either Wegovy or Mounjaro — the app makes no distinction between the two, and works equally well for both.

The most relevant feature here is dose and injection logging. Whether you are on a 0.5 mg Wegovy pen or a 5 mg Mounjaro pen, you can log each weekly injection — recording the dose strength, the date, and the injection site — so your full history is always clear and in one place. The app tracks your site rotation and suggests where to inject next, which is useful regardless of which medicine you are using.

If you want to monitor how you feel across your journey — useful when switching between medicines or titrating up — the side-effect and daily check-in tracking lets you log symptoms, energy, mood, and sleep over time. That kind of record can be genuinely helpful to bring to your prescriber appointments, whatever stage you are at.

Any decision about which medicine to take, or whether to switch from one to the other, should always be made with your prescriber or doctor — they are the right person to weigh up your individual history and circumstances. GLP Trackr helps you record your journey; it is not a substitute for clinical advice.

Ready to keep track of every dose and how you feel along the way? GLP Trackr is free to try for 7 days — available now on the App Store and Google Play.