UK Slimming Injections: Understanding Injection Sites and Rotation

Both Mounjaro and Wegovy are administered as subcutaneous injections — meaning the medicine is delivered into the layer of fatty tissue just beneath the skin. The three commonly used sites are the abdomen (avoiding the area around the navel), the front of the thigh, and the outer upper arm. Your prescriber or doctor will have guided you on the sites suitable for you, and the patient information leaflet that comes with your pen is the definitive reference for technique.

Why rotation matters

Using the same spot repeatedly can cause changes to the tissue under the skin — a condition sometimes called lipohypertrophy — which may affect how the medicine is absorbed. Moving to a different site each week, and varying the exact spot within each area, helps avoid this. Many people find it straightforward in the beginning but lose track over time, especially across several months of weekly injections.

Common questions about sites

• Which site is most comfortable? This varies from person to person. The abdomen is the most commonly used site, but comfort and ease of access depend on individual factors — discuss preferences with your prescriber or doctor.
• Can I inject into the same general area for a few weeks? If you do use the same area (for example, the abdomen), aim to vary the exact spot within that area each time, moving at least a few centimetres from the last injection point. Check your patient information leaflet for the specific guidance for your medicine.
• What if I notice a lump or skin change at an injection site? Mention any persistent lumps, redness, or skin changes to your healthcare professional promptly.

For a broader overview of how these medicines work and what the injection journey looks like, the weight-loss injections guide covers the wider picture. You may also find it useful to read about slimming injections generally or explore how slimming injections are accessed through healthcare services.

Remembering which site you used last week — and exactly where within that area — is the kind of detail that slips easily. GLP Trackr's injection-site tracking feature is built specifically for this: log each injection with the site and date, and the app uses your history to suggest where to inject next, so rotation becomes automatic rather than something you have to remember.

Alongside site tracking, you can log the dose strength and time of each injection, building a clear record of your full treatment history. If you ever need to discuss your injection schedule with your prescriber or doctor, you have everything in one place — including a doctor report summary you can bring to your appointment.

Dose reminders mean a weekly injection is less likely to be forgotten, which matters for staying consistent on a once-weekly schedule.

If you are just getting started with tracking your weekly routine, practical tips for managing your slimming injection schedule is worth reading alongside this page.

Always follow the guidance of your prescriber or doctor regarding injection technique, site selection, and your personal treatment plan — they know your full history, and the app is a companion to that care, not a substitute for it. If you experience any injection-site reaction that is severe, spreading, or does not settle, contact your healthcare professional promptly. Any side effects worth reporting should be raised with your prescriber and, where required, reported to your national pharmacovigilance scheme (such as the UK's Yellow Card scheme).

Ready to take the guesswork out of injection-site rotation? Download GLP Trackr on the App Store or Google Play and start a free 7-day trial — your injection history, rotation suggestions, and dose reminders all in one place.