Quick Summary

Mounjaro is injected once weekly into fatty tissue (subcutaneous). Common sites include the abdomen, thigh, or upper arm. Rotate injection sites each week. The pen is single-use only. Our pharmacist provides training during your consultation.

How to Inject Mounjaro: Step-by-Step Guide

Medical Review: Reviewed by registered pharmacist. Last Updated: December 2025. Location: Glasgow, Scotland.

Step-by-Step Injection Instructions

1. Preparation

Remove the pen from the refrigerator 30 minutes before injection (let it reach room temperature)
Wash your hands thoroughly with soap and water
Choose your injection site (abdomen, thigh, or upper arm)
Clean the injection site with an alcohol swab and let it dry
Check the pen to ensure it contains the correct dose

2. Injection Sites

You can inject Mounjaro into any of these areas:

Abdomen: At least 2 inches away from your navel, in the fatty area
Thigh: Front of the thigh, in the fatty area
Upper Arm: Back of the upper arm, in the fatty area (may require assistance)

Important: Rotate injection sites each week. Do not inject into the same spot twice in a row, and avoid areas with scars, moles, or skin irritation.

3. Injection Process

Remove the pen cap
Hold the pen like a pencil, with the needle pointing down
Pinch a fold of skin at the injection site
Insert the needle at a 90-degree angle (straight in) into the pinched skin
Press the injection button and hold for 10 seconds
Release the button and remove the needle
Release the pinched skin
Dispose of the pen safely in a sharps container

4. After Injection

If you see a small amount of blood, apply gentle pressure with a clean tissue
Do not rub the injection site
Dispose of the pen in a sharps container (do not throw in regular trash)
Note the date and injection site in your treatment log

Safety Tips

Never share your injection pen with anyone
Always use a new pen for each injection
Store unused pens in the refrigerator (2-8°C)
Do not freeze the medication
Keep pens out of reach of children
If you're unsure about anything, contact your pharmacist

When to Seek Help

Contact your pharmacist or seek medical attention if you experience:

Significant pain or swelling at the injection site
Signs of infection (redness, warmth, pus)
Accidental injection into muscle or vein
Any concerns about your injection technique

Frequently Asked Questions

Where should I inject Mounjaro?

Mounjaro should be injected into the fatty tissue under the skin (subcutaneous). Common injection sites include the abdomen (at least 2 inches from the navel), thigh, or upper arm. Rotate injection sites each week.

How often do I inject Mounjaro?

Mounjaro is injected once weekly, on the same day each week. You can inject at any time of day, with or without food.

What should I do if I see blood after injecting?

A small amount of bleeding is normal. Apply gentle pressure with a clean tissue or cotton ball for a few seconds. If bleeding continues or is excessive, contact your pharmacist.

Can I reuse the injection pen?

No, Mounjaro pens are single-use only. Each pen contains one dose and should be discarded after use, even if some medication remains.

What if the injection hurts?

Mild discomfort at the injection site is normal. To minimise pain, let the pen reach room temperature before injecting, rotate injection sites, and ensure you're injecting into fatty tissue, not muscle.