Monthly Weight Loss Injections: What You Need to Know

Prescription injectable medicines used for weight management — including Mounjaro and Wegovy — are both given as once-weekly subcutaneous injections, not once monthly. They are prescription-only medicines that your prescriber determines the schedule and dose for, based on your individual circumstances.

Weekly injections, monthly milestones

Although the injection itself is weekly, many people find it helpful to think in monthly blocks: a new prescription cycle, a scheduled check-in with their prescriber, or simply reviewing how the past four weeks have felt. Tracking each week carefully means you arrive at those monthly moments with a clear picture of your progress, any side effects you have noticed, and how your body has responded.

Injection sites and rotation

Both Mounjaro and Wegovy are injected into fatty tissue — commonly the abdomen, front of the thigh, or upper arm. Rotating the injection site each week is widely recommended to help avoid skin irritation or changes at the injection site. Your prescriber or the patient information leaflet that came with your pen will give you guidance specific to your medicine. For a broader look at injection practices, the weight loss injections overview covers the key principles in more detail.

Keeping track across a monthly cycle

With a weekly injection, it is easy to lose count — especially during busy weeks or when your routine changes. Logging each dose as you go means you always know exactly where you are in your schedule, which sites you have used recently, and what is coming up. You can read more about how individual weight loss injections work and what to expect from your injection routine. If you are researching your options more broadly, our page on monthly weight loss injection programmes may also be useful context.

The most relevant feature for anyone managing a weekly injection schedule is GLP Trackr's injection-site tracking and rotation tool. Each time you inject, you log the site — abdomen, thigh, or arm — and the app keeps a history of where you have been, then suggests where to inject next. Over a monthly cycle, that means rotation happens automatically rather than relying on memory.

Alongside site tracking, the dose logging feature lets you record each injection with its date, time, and dose strength, so your full monthly picture is always in one place. And if life gets in the way, the built-in dose reminders mean your weekly schedule stays front of mind without you having to think about it.

When you have a review appointment with your prescriber — whether that is monthly or at another interval — you can bring a clear, organised record of every injection, any side effects you noticed, and how your progress looked week by week. That kind of detail can make those conversations more useful for both of you.

Any questions about your dose, your schedule, or whether your injection routine is right for you should always go to your prescriber or doctor — they have the full picture of your health history. GLP Trackr is there to help you record and reflect, not to replace their guidance. If you are also curious about accessing or sourcing injectable medicines, the page on obtaining weight loss injections explains what GLP Trackr is and is not able to help with.

Ready to take the guesswork out of your weekly injection routine? GLP Trackr's site-rotation tracker and dose log keep your monthly record clear and complete — available free on the App Store and Google Play, with a 7-day trial to get started.