Weight management

Getting to grips with your Mounjaro pen: troubleshooting & top tips

Last reviewed:
April 11, 2024
Next review:
April 11, 2025

You might not have self-administered an injection before, let alone been responsible for the correct storage, management and disposal of injectable medications and equipment. It’s not as daunting as you might think! To make sure you’re comfortable and confident, our clinical team have shared their top 10 troubleshooting tips; so you can avoid any uncertainty.

Remember, always read the Patient Information Leaflet and User Guide that comes with your medication. We also have a dedicated step-by-step guide focused on how to use your Mounjaro KwikPen.  

1. I didn’t put my KwikPen in the fridge when my delivery came

It’s essential to store Mounjaro as directed, because incorrect storage will spoil the medication. To make sure it arrives with you at the correct temperature we package it with a special (100% natural) material called Woolcool and additional gel ice packs. Both of these mean your order will arrive at the correct temperature. Once you receive your order, you should immediately check everything is correct and then put the KwikPen into your fridge as quickly as possible. It must be sorted in the fridge before first use, between 2°C to 8°C.

If your KwikPen is delivered with the ice packs melted, or you’ve been unable to store it in the fridge straight away, don’t worry. It can temporarily be outside of refrigerated conditions for a maximum of 24 hours before it needs to be refrigerated again; without affecting the in-use period or shelf life of the product. However, we always recommend refrigerating as soon as possible.  

2. My first injection was cold and uncomfortable

The first injection with any new KwikPen might be slightly more uncomfortable. That’s because it’s been refrigerated at a low temperature and cold injections are always more uncomfortable than medication stored at room temperature. It might be tempting to take it out of the fridge before use (or store it at room temperature) but doing this will spoil the medication. You can only store it at room temperature AFTER you administer the first injection from any new KwikPen.

3. Does it matter that I didn’t wash my hands?

Practicing good hand hygiene is essential when injecting Mounjaro. You should thoroughly wash your hands, prepare a clean & sanitary surface to work from and use the swabs provided to wipe down your KwikPen. If someone is injecting your dose for you then they also need to practice good hand hygiene. Not doing so increases the risk of infection at your inject sites, not to mention surface bacteria forming on your KwikPen. You’ll use one single KwikPen to administer four doses, so hygienic handling and storage is essential to minimise risks.

4. I always inject in the same place

You can inject in the same area of your body (stomach, thigh or the back of your upper arm) but you need to rotate the injection site with every injection. Never inject in the exact same location, as this can increase the risk of infection or hard lumps forming under the skin. And if you prefer to inject in your stomach, remember to always inject at least 2 inches away from your belly button.

5. Not changing the needle for each injection

The needles for your KwikPen are single-use and need to be replaced for each injection. Using the same needle more than once can lead to a range of problems, such as “blunting” of the needle (means you might not get a full dose), increased risk of infection and injection site reactions (hard lumps forming under the skin). We’ll send you a supply of 100 needles with your first order, meaning you have enough for up to two years’ worth of weekly injections.

6. You can’t see the needle head once you’ve attached it

New needles come with an outer and inner needle shield. Both of these need to be removed before you can inject your dose. Make sure to closely follow the steps for preparing your KwikPen.

7. You can’t see the right icons in the pen dose window

The step-by-step guide shows you which icons you should see in the dose window at two different key stages – when priming your KwikPen and when injecting your dose. Closely follow the steps and troubleshooting tips for these key stages. Often the issue is easily resolved by changing the needle, performing the priming steps accurately or adjusting your finger pressure on the dose knob.

8. You’ve taken your 4th dose but there’s still some medicine left in the pen

This is perfectly normal. The KwikPen has a “contingency” amount of Mounjaro in the pen, designed to allow for four full doses plus some extra for the priming steps. This extra amount is not enough for a 5th dose and the KwikPen itself will not allow for a 5th dose to be injected into your body.

9. You forget to take a dose at the right time

We always recommend setting an alarm or reminder on your phone to build the habit of routine. But life can get in the way sometimes! These things happen, but it’s important to understand what to do next. It also depends which medication you’re taking. Never double dose to make up for a forgotten dose.


  • If it’s been 4 days or less since you should have injected, use it as soon as you remember and then take your next dose as usual on your scheduled day.  
  • If it’s been more than 4 days since you should have injected, skip the missed dose and then inject your next dose on your usual scheduled day.


  • If it’s been 5 days or less since you should have injected, use it as soon as you remember and then take your next dose as usual on your scheduled day.  
  • If it’s been more than 5 days since you should have injected, skip the missed dose and then inject your next dose on your usual scheduled day.

10. You’re travelling and will need to inject while away from home

You can easily travel with your KwikPen, but just make sure you carefully plan how you’re going to transport and store your KwikPen. The key consideration is temperature – the pen can’t get too hot or too cold. To prevent it getting too hot (especially when in a warmer climate) you might want to consider a good quality portable cool bag. To prevent it getting too cold, if you’re flying, pack it in your hand luggage to avoid it freezing in the luggage hold. However, we do recommend packing your needles in your hold luggage to avoid any issues at airport security.

If you’re unsure about anything, your friendly clinical team is on hand to talk you through all aspects of managing your KwikPen injections. Starting your weight loss treatment with Phlo Clinic means access to safe & supported weight loss injectables that can help you achieve up to a 20% reduction in bodyweight.

Got a Mounjaro question? Explore more about our weight management service and put your mind at ease.

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