Mounjaro
How to inject Mounjaro correctly, choose injection sites, and rotate safely
What is Mounjaro?
Mounjaro (tirzepatide) is a once-weekly injectable medication for chronic weight management and type 2 diabetes. It is a dual GIP/GLP-1 receptor agonist — the first in its class — working on two gut hormones simultaneously to reduce appetite and improve blood sugar regulation.
🔬 Mounjaro vs Wegovy — key difference
Both are weekly injectables for weight management, but Mounjaro acts on two receptors (GIP and GLP-1), while Wegovy (semaglutide) acts on one (GLP-1 only). Clinical trials show Mounjaro may produce greater average weight loss. Your doctor will recommend the most appropriate medication for your individual situation.
Dose Escalation Schedule
Mounjaro is started at a low dose and increased gradually (typically every 4 weeks) to reduce gastrointestinal side effects:
| Weeks | Dose | Purpose |
|---|---|---|
| Weeks 1–4 | 2.5 mg | Starting dose — minimise side effects |
| Weeks 5–8 | 5 mg | First escalation |
| Weeks 9–12 | 7.5 mg | Second escalation (if tolerated) |
| Weeks 13–16 | 10 mg | Third escalation (if needed) |
| Weeks 17–20 | 12.5 mg | Fourth escalation (if needed) |
| Week 21+ | 15 mg | Maximum maintenance dose |
Your doctor may slow the escalation schedule if you experience significant nausea or other side effects.
What to Have Ready Before Each Injection
Gather the following before you begin. Tick each one off as you confirm it is ready.
✅ Mounjaro injection checklist — tick as you gather each item
🗑️ Sharps disposal
When your sharps container is full, seal the lid securely. Do not put it in household rubbish. Return to your pharmacy or check your local council website for the nearest free drop-off point.
Approved Injection Sites
Abdomen
The same general area of the abdomen (stomach). Avoid the 5 cm zone around the navel.
Front of Thigh
The upper or middle area of the front of the thigh — left or right.
Upper Arm
The outer, back surface of the upper arm. May require assistance for self-injection.
How to Inject – Step by Step
Prepare
Wash hands. Allow pen to reach room temperature (30 min from fridge). Do not shake.
Check
Inspect the pen — check expiry date and that the liquid is clear and colourless. Do not use if discoloured.
Select & clean site
Choose your injection site and wipe with an alcohol swab. Allow skin to dry.
Remove cap & inject
Remove the cap. Pinch skin gently. Place pen flat against skin and press the button. You will hear a click.
Hold 10 seconds
Keep pen pressed against the skin for 10 seconds after the click to ensure the full dose is delivered.
Rotate & dispose
Rotate to a new spot. Dispose of the pen safely in a sharps container — never reuse.
💡 Tip — changing injection day
If you need to change your injection day, it is acceptable to inject up to 3 days before or after your usual day (as long as it has been at least 4 days since your last dose). Contact your doctor or pharmacist if unsure.
Storage
Store unused pens in the refrigerator at 2–8°C. Do not freeze.
A pen in use may be kept at room temperature (up to 30°C) for up to 21 days.
Keep pens in the outer carton to protect from light.
Keep out of reach of children and pets.
Reference Graphic
Mounjaro injection sites: abdomen, thigh, and upper arm — see panel 8 of the Arami resource guide
Questions about Mounjaro or your weight management journey?
Book a review appointment to track your progress and ensure your treatment is working effectively.
Medical Disclaimer
This information is general in nature and does not replace the manufacturer's instructions or your prescriber's advice. Always refer to the Consumer Medicines Information (CMI) leaflet provided with your medication and follow the instructions of your healthcare provider.