Where Do You Inject Mounjaro? Injection Sites Explained

Each of the three approved subcutaneous injection areas has practical characteristics worth understanding. Always refer to the patient information leaflet (PIL) that came with your pen and follow the guidance of your prescriber or doctor — what follows is general information, not a replacement for that advice.

Abdomen

The abdomen is the most commonly used site. The usable area is generally the soft tissue around the navel, avoiding a radius of a few centimetres from the navel itself and steering clear of the waistband area. Many people find this site easy to reach and comfortable to self-inject.

Front of the thigh

The front and outer portion of the thigh is another widely used option, particularly if you prefer not to inject into the abdomen. Keeping to the middle portion of the thigh — not close to the knee or inner thigh — is the general guidance described in most patient information materials.

Upper arm

The outer area of the upper arm can also be used, though self-injection here may be less straightforward than the other two sites. Some people ask a household member to help with this location.

Why rotation matters

Using the same spot repeatedly can cause lipohypertrophy — a build-up of fatty tissue under the skin that may affect how the medicine is absorbed. Rotating systematically across sites and within each site (not always injecting in exactly the same point) helps keep skin tissue healthy over time. For a practical overview of injection technique and site guidance, the electronic Medicines Compendium (eMC) hosts the full Mounjaro patient information leaflet.

If you are also curious about injection sites for the other major GLP-1 medicine, the same general principles apply — see where to inject Wegovy for a comparison. For a broader look at the weekly injection process itself, how to do a Mounjaro injection covers what to expect step by step. And if you are thinking about the best time of week to schedule your dose, choosing the best day to inject Mounjaro has more context.

Keeping a mental note of which site you used last week — and exactly where within that site — is easy to forget, especially once the routine becomes second nature. GLP Trackr's injection-site tracking is built specifically for this: log the site after each injection and the app keeps a running rotation history, so you always know where you injected last and where to go next.

Alongside site tracking, dose logging means every injection is recorded with its date, time, and strength — useful if you ever need to check when your last pen was started, or want to bring a clear picture of your schedule to a prescriber appointment. Dose reminders can also be set so a weekly injection is never accidentally missed.

All of this lives in one place alongside any other aspects of your journey you want to follow — weight, side effects, food, and more. Visit our weight loss injections guide for a broader look at managing life on a GLP-1 medicine.

If you notice any skin reactions at injection sites — redness, swelling, or changes in the skin — mention these to your prescriber or doctor. GLP Trackr is a tracking tool, not a medical service, and any concerns about your injection sites or how you are getting on with the medicine should always be discussed with your healthcare professional.

Ready to make rotation effortless? GLP Trackr is free to download on the App Store and Google Play, with a 7-day free trial — log your first injection site today and let the app handle the rotation tracking from there.