How to Use the Mounjaro KwikPen: A Practical Guide for People Already Prescribed It

Mounjaro is injected subcutaneously — into the fatty tissue just beneath the skin. The three sites most commonly used are the abdomen (avoiding the area directly around the navel), the front of the thigh, and the upper arm. Each of these areas provides enough accessible tissue for a comfortable injection for most people.

Why rotation matters

Rotating between sites — and within each site — helps avoid lipohypertrophy, a build-up of fatty or hardened tissue that can develop if the same small spot is used repeatedly. Injecting into hardened tissue can affect how the medicine is absorbed, so consistent rotation is worth building into your weekly habit.

A few general points to be aware of

• Avoid skin that is bruised, tender, scarred, or has an active skin condition.
• Each pen is for single use only and should never be shared.
• Allow the pen to reach room temperature before injecting — check the leaflet that came with your pen for the recommended time, as this can vary.
• The pen does not need to be primed before use.
• After the injection, check the viewing window to confirm the dose was delivered — your leaflet explains exactly what to look for.
• Used pens should be disposed of in an approved sharps container; ask your prescriber or pharmacist how to obtain one locally.

Where to find the full technique guidance

Step-by-step injection technique — including how to position the pen, the angle of insertion, and how to confirm the full dose was given — is covered in the patient information leaflet supplied with your medication and on the electronic Medicines Compendium (eMC) entry for Mounjaro. Your prescriber or a pharmacist can also walk you through the process. For a broader look at using Mounjaro as part of your weekly routine, including what to do before and after your injection day, that guide covers the wider picture. You may also find it useful to read about general pen handling tips for Mounjaro alongside this page.

Remembering which site you used last week — and exactly where within that site — is easy to forget, especially once the weekly injection becomes routine. GLP Trackr's injection-site tracking feature is built specifically for this: log your site after each injection and the app keeps a rotation history, then suggests your next site so you never have to guess.

Alongside site tracking, the app logs the dose strength, date, and time of each injection, giving you a clear record you can refer back to or share with your prescriber at appointments. Dose reminders mean your weekly schedule stays consistent even when life gets busy — a useful safety net for a once-weekly medicine where timing matters.

For a deeper look at everything the app tracks around your injection routine, the KwikPen tracking guide in GLP Trackr goes into more detail. You can also explore all the tools available to people on injectable weight-loss medicines through the weight-loss injections hub.

GLP Trackr is free to try for 7 days — available on the App Store and Google Play. If you want your injection history, site rotation, and dose log all in one place from your very first pen, it takes less than a minute to set up.

If you experience any pain, swelling, or skin reaction at an injection site that concerns you, or if you are unsure about any aspect of your injection technique, contact your prescriber or a healthcare professional promptly. GLP Trackr is a tracking tool and is not a substitute for guidance from your own clinician.