Mounjaro: What Is It and What Is It Used For?

Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist — meaning it acts on two appetite-related hormone pathways rather than one. GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) are both naturally occurring hormones involved in regulating hunger and fullness signals. By acting on both receptors, tirzepatide influences how the body responds to food.

In practical terms, many people prescribed Mounjaro report an increased sense of fullness after eating, a reduction in appetite, and a decrease in what is sometimes called "food noise" — the persistent mental preoccupation with food. These are commonly reported effects; individual experience varies, and results depend on many factors including diet, activity, and the dose your prescriber has determined is right for you.

Mounjaro is supplied as a pre-filled pen device and is injected once weekly. Common injection sites include the abdomen, the front of the thigh, and the upper arm. The medicine is typically started at a lower dose and adjusted over time — always under the direction of your prescriber. For a broader look at the mechanism behind this medicine, see our guide to how Mounjaro works.

Mounjaro carries the black triangle symbol (▼) in some countries, indicating it is subject to additional monitoring. Any side effects should be reported to your healthcare professional and, where applicable, to your national reporting scheme (such as the UK's Yellow Card scheme).

Mounjaro is not insulin. It is not a cosmetic procedure. It is a prescription medicine whose suitability is determined solely by a qualified prescriber based on your individual health history. If you are curious how it compares with semaglutide-based options, you may find it useful to read about what Wegovy is, or explore a broader overview of what GLP-1 medicines are. For more detail specifically on this medicine's profile, our page on what Mounjaro is goes further.

GLP Trackr is a companion app built specifically for people already prescribed Mounjaro and Wegovy. The feature most relevant when you are getting to grips with a new medicine is dose and injection logging — every injection you take can be recorded with its dose strength, date, time, and site. The app tracks your injection-site rotation history and suggests your next site, so you never have to remember where you last injected.

Beyond logging shots, GLP Trackr's insights and analytics help you see patterns in your own data over time — how your weight, energy, mood, and side effects relate to each other and to your weekly dose schedule. This kind of joined-up picture can be genuinely useful to bring to your prescriber appointments, and the app's doctor report feature makes it easy to share a clear summary of your journey.

Everything the app records is for your own understanding and to support conversations with your healthcare team — it is not a substitute for their guidance. Any questions about your dose, your suitability for this medicine, or how it is working for you should always go to your prescriber or doctor, who knows your full medical history.

Ready to start tracking? Download GLP Trackr on the App Store or Google Play — your first seven days are completely free, with no commitment required.