Daily Injection for Weight Loss: What You Need to Know

Mounjaro and Wegovy are both prescription-only, once-weekly injectable medicines used in weight management. Mounjaro contains tirzepatide, a dual GIP and GLP-1 receptor agonist, while Wegovy contains semaglutide, a GLP-1 receptor agonist. Both act on appetite-regulating pathways, and many people experience a reduced sense of hunger and greater fullness after eating — though individual responses vary.

Injection sites and rotation

Both medicines are injected under the skin (subcutaneously). The three commonly used sites are the abdomen, the front of the thigh, and the upper arm. Rotating between sites with each injection is important: using the same spot repeatedly can cause tissue changes that affect how well the medicine is absorbed. A simple rotation pattern — for example, moving around the abdomen in a clockwise sequence, or alternating between sites each week — can help.

Your prescriber or the patient information leaflet that came with your pen will give you specific guidance on technique. For general information on weight-loss injection basics, or more detail on injecting Mounjaro specifically, those pages cover the key points. If you are also managing diabetes and have been prescribed an injectable for that purpose, the considerations around diabetes injections and weight management may also be relevant to your situation.

Keeping your schedule on track

Because the injection is only once a week, it can be easy to lose track of which day you last injected, which site you used, and what dose strength you are currently on — especially as your prescriber adjusts your dose over time. Keeping a clear record matters both for your own consistency and for conversations with your prescriber at review appointments.

The most useful feature for anyone on a weekly injectable is injection-site tracking and rotation. GLP Trackr lets you log the site you used for each injection — abdomen, thigh, or upper arm — and keeps a history so you can see at a glance where you injected last time and which site is due next. Taking the guesswork out of rotation means one less thing to think about each week.

Alongside site tracking, dose logging records the date, time, and dose strength of every injection in one place. Combined with the app's dose reminders, this means you are far less likely to miss a scheduled injection or lose track of where you are in your titration schedule — something that matters particularly when your prescriber has recently adjusted your dose.

If you want a broader view of everything involved in managing a weekly injectable, the weight-loss injections hub brings together guidance on sites, schedules, side effects, and more.

GLP Trackr is available free on the App Store and Google Play. Start a 7-day free trial and see how straightforward it becomes to stay consistent with your weekly injection routine — every site, every dose, logged in one place.

Any questions about your injection technique, dose, or schedule should be directed to your prescriber or doctor — they know your full medical history and are best placed to advise you. If you experience any unexpected reactions at an injection site or elsewhere, contact your healthcare professional promptly. Adverse effects can also be reported to your national reporting scheme (such as the UK Yellow Card scheme) as well as to your healthcare professional.