Mounjaro Injection Sites UK — How to Inject Correctly

Mounjaro (tirzepatide) is administered as a weekly subcutaneous (under-skin) injection. The technique is simple — the autoinjector pen makes the injection largely self-administering — but understanding the approved sites, rotation protocol, and technique tips reduces injection site reactions and ensures consistent medication delivery.

Quick answer: Mounjaro can be injected into three approved sites: the abdomen (stomach area, excluding the 5cm around the navel), the thigh (outer, upper area), and the upper arm (outer area, back of the arm). The abdomen is typically the easiest and most commonly used site. Rotate between sites and within each site — do not inject the same spot more than once per month. Allow the pen to reach room temperature before injecting.

Note: Food supplements should not replace a balanced diet. Always consult your GP or pharmacist before taking supplements if you are on prescribed medication, pregnant, or have a medical condition. Nothing in this post constitutes medical advice.

Approved injection sites

Site	Location	Notes
Abdomen	Lower or upper belly — stay at least 5cm from the navel	Most commonly used; easiest to self-inject; best access to subcutaneous tissue
Thigh	Outer, front of thigh — middle third	Good second site; easy to see and access
Upper arm	Back/outer area of upper arm	More difficult to self-administer without practice; easier with a short device

Step-by-step injection technique

Prepare: remove the pen from the fridge at least 30 minutes before injection. Cold medication can cause more discomfort and may reduce absorption.
Check the pen: verify the dose window shows the correct dose. Check the expiry date. Do not use if the medication appears cloudy or discoloured.
Choose and clean the site: select your rotation site. Clean with an alcohol wipe and allow to dry completely (wet skin increases sting).
Prepare the skin: pinch a fold of skin between thumb and forefinger if you have less subcutaneous tissue. On the abdomen, this is often not necessary.
Inject: press the autoinjector firmly against the skin. Press the button. Hold for the full count (usually 5–10 seconds, as indicated on the device). You should hear/feel a click at the start and end.
Remove and dispose: lift the pen straight up. Place directly into a sharps container. Do not recap.

Injection site rotation protocol

Injecting the same site repeatedly causes lipohypertrophy — a hardened, fatty lump that absorbs medication poorly and inconsistently. The standard rotation:

Divide the abdomen into four quadrants (top left, top right, bottom left, bottom right)
Rotate around the quadrants week by week
Within each quadrant, space injections at least 2–3cm apart
Track where you injected — most people find a simple tick chart on their calendar works

Reducing injection site reactions

Always let the pen reach room temperature (30+ minutes) before injecting
Ensure the alcohol from the wipe is fully dry before injecting
Inject slowly — do not rush the device
Rotate sites consistently
Apply gentle pressure after injecting (no rubbing) for 5–10 seconds

Frequently Asked Questions

Where do you inject Mounjaro?

Approved injection sites are the abdomen (at least 5cm from the navel), the outer thigh, and the outer upper arm. The abdomen is the most commonly used and typically the most comfortable site. Rotate between and within sites to prevent lipohypertrophy.

Does the Mounjaro injection hurt?

Most people describe it as minimal discomfort — a brief pinch at most. The autoinjector pen is designed to make the injection as comfortable as possible. Cold medication and wet alcohol wipes are the most common causes of increased discomfort — let the pen warm up and allow the wipe to dry completely.

Can I inject Mounjaro in my stomach?

Yes — the abdomen is the most commonly used and recommended site. Inject at least 5cm away from the navel and not through the navel itself. Avoid existing scars, skin conditions, or areas of lipohypertrophy (hardened lumps from repeated injection).

How do I store Mounjaro?

Store in the refrigerator (2–8°C) before first use. Do not freeze. After first use, can be stored at room temperature (below 30°C) for up to 21 days. Keep away from heat and direct sunlight.