How to inject Mounjaro®: Step-by-step guide

Before you inject Mounjaro®: Get everything you need ready

1. Get everything laid out and ready, including: 

• Mounjaro® pen

• New sterile needle

• Alcohol swab

• Gauze

• Sharps container
  

2. Check the pen: 

• Make sure the pen label matches your prescription

• Check that the medicine inside the pen is clear and not cloudy - If your pen appears cloudy, damaged, or frozen - do not use it

• Check the pen isn’t damaged
  

3. Wash your hands: Use soap and water and dry thoroughly afterwards.
   

4. Choose your injection site - choose from your: 

• Stomach (at least 5cm away from your belly button)

• Front of thigh

• Back of upper arm 

Make sure you rotate your injection site each week

You don’t have to inject in the same place every time. Many people choose to rotate their injection site each week - for example, using the stomach one week, then the thigh the next. Over time, you’ll get a feel for which areas work best for you, making your injections more comfortable and easier to manage.

5. Clean the site: Wipe the area with an alcohol swab and allow it to dry.

Mounjaro® injection instructions: 10 quick and easy steps

1. Remove the pen cap

2. Attach a new needle securely to the pen

3. Remove the outer needle cap, keeping the needle inner cap on until ready to use

4. Prime the pen before your first use (remove the inner needle cap): 

• Hold it upright, turn the dose knob so you hear 2 clicks (this is the prime position/setting)

• Gently tap the clear section of the pen - this help remove any unwanted air bubbles 

• Still holding it upright, press the button all the way and hold for 5 seconds, ensuring you see a small amount of medicine released from the needle - your pen is now ready to use!

• If you do not see any medicine released, repeat the process until you do

5. Turn the dose knob all the way so the number 1 is clearly shown in the dosage window

6. Insert the needle straight (90°) into your cleaned injection site

7. Press the injection button down fully - hold it for 5 seconds to ensure the full dose is delivered

8. Check that the dose window reads ‘0’ - this confirms that your dose has been fully delivered. 

• If it’s not at 0, you can re-insert the needle and repeat the process, holding the button down firmly until 0 is clearly shown in the dosage window

9. Remove the needle at the same angle. Carefully replacing the outer cap, unscrewing it, and disposing of it in your sharps container

10. Replace the pen cap and store the pen safely according to manufacturer’s guidance.

Weekly routine and tips for taking Mounjaro® injections

• Inject once per week, ideally on the same day and time

• If you need to change your injection day, make sure there are at least 72 hours between doses

• Rotate injection sites to prevent irritation

• Store unused pens in the fridge (2–8°C). Do not freeze

• Keep already-open pens at room temperature and away from direct sunlight.

What to watch out for

Here are a few things to look out for when using Mounjaro - read our guide on common Mounjaro® side effects for more details.

• Mild redness or tenderness is normal

• Seek medical advice if you experience severe pain, swelling, or signs of infection at the injection site

• If your pen appears cloudy, damaged or frozen - do not use it

• If you accidentally take more than your prescribed dose, contact your doctor immediately

Pharmacist tips for easier injections

“As a pharmacist, I often reassure patients that feeling a bit nervous at first is completely normal. A few simple habits and routines can make your Mounjaro® injections much more comfortable, less nerve-racking and easier to manage over time:

• Rotate your injection site each week to help prevent skin irritation

• Try to inject at the same time each week to keep a steady routine

• Store your pen in the fridge, but never freeze it

• If it’s been refrigerated, let the pen sit at room temperature for around 30 minutes before injecting, as this can help reduce discomfort

Taking your time and sticking to a routine can make injections feel like a smaller, more manageable part of your week.”
– Peter Thnoia, PillTime SuperIntendent

FAQs about injecting Mounjaro®

• Can I use the same injection spot every week?

  No. You can use the same general area but change the exact spot each week to help your skin recover and ensure the medicine absorbs properly.

• What if I miss a dose?

  You can inject it within 4 days (96 hours) of your usual time. If more than 4 days have passed, skip that dose and inject again on your next scheduled day.

• Does the injection hurt?

  Some people feel mild discomfort or stinging. This usually passes quickly. Using the techniques shown previously and rotating sites helps reduce this.

• Can I inject into my arm by myself?

  Can I inject into my arm by myself?

  It’s possible, but can be tricky. Most people find the stomach or thigh easier for self-injection. Ask for help if using the upper arm as an injection site.

• How to inject Mounjaro® in thigh area

  It’s important to choose the front or outer area of the upper thigh to inject Mounjaro® and NOT the inner thigh. You can rotate injections sites between thighs if you wish, so inject into your left thigh one week and your right thigh the next, for example. Once you have chosen your site to inject in the thigh, follow our Mounjaro® injection instructions. 

• How should I store my pen?

  Keep unused pens in the fridge (2–8°C). Once in use, store according to instructions and away from direct sunlight. Never freeze your pen.

• What’s the best place to inject Mounjaro® for weight loss?

  Mounjaro® is designed to be injected just under the skin. The recommended injection areas included in the Mounjaro® instructions are:

  • Stomach (abdomen)
    A common choice for many people, as it’s easy to access. Avoid the belly button area and inject at least 2 inches away.

  • Thighs
    The front or outer part of the upper thigh works well and can feel more comfortable for some people.

  • Back of the upper arms
    This area can also be used, though some people prefer help from someone else to inject here.

  What to keep in mind

  • There’s no single “best” injection site for weight loss results - all approved areas work in the same way

  • Rotating injection sites each week can help reduce redness, soreness, itching or swelling

  • If you notice irritation in one area, switching to another approved site can give your skin time to recover. If not, contact your Pharmacist.

  Over time, you’ll find the injection sites that feel most comfortable for you and fit easily into your weekly routine.

• Where should I avoid injecting Mounjaro®?

  There are a few areas you should avoid when injecting Mounjaro®. Try not to inject:

  • In or too close to your belly button - keep at least 2 inches away

  • Into skin that is scarred, bruised, sore or irritated

  • Into muscle - Mounjaro® is designed to be injected just under the skin, not into muscle

  Choosing the right spot helps make injections more comfortable and supports safe, effective use.

We’re here to help

If you’d like help or guidance on any aspect of Mounjaro® or other medications, speak to a PillTime pharmacist for friendly, professional advice - from a qualified and experienced pharmacist. We’re here to make your weight loss journey simple, safe, and fully supported.

Note

This guide was produced by PillTime Pharmacy, a GPhC-regulated UK online pharmacy. Always use prescription medicines exactly as directed by your clinician.