How to Store Mounjaro
Mounjaro is a highly effective weight loss injection, but it must be stored properly to make sure you get the best results from it.
In this guide, we’ll explain the best ways to store Mounjaro pens, what temperature they need to be kept at, and how to safely travel with them.
Medically reviewed by
Dr Zoe MillerLast reviewed: 22 Jan 2025
How to store Mounjaro
How you should store your Mounjaro pens will depend on whether or not they are currently in use.
All unused Mounjaro medication should be stored in the fridge until it is required for use.
To store your unused Mounjaro pens, you should follow the guidance below:
- unused Mounjaro pens should be kept in the fridge between 2 and 8°C
- keep Mounjaro pens in their original, unopened packaging that clearly displays the use-by date
- avoid keeping in refrigerators that are likely to fluctuate in temperature or are at risk of failing
- do not freeze Mounjaro – if any of the pens become frozen you must throw them away
- unused pens can be used until the expiry date printed on the label if the pen has been stored in the refrigerator
If you are currently using a Mounjaro pen, it should be stored as follows:
- keep refrigerated (although it can be kept at room temperature up to 30°C for up to 21 days)
- keep away from heat
- keep out of reach and sight of children
- dispose of the used pen 30 days after its first use or after receiving 4 weekly doses
Does Mounjaro need to be refrigerated?
Yes, Mounjaro must be kept in the fridge until you first use it. Once the pen is in use, you can continue to refrigerate it or it can be kept out of the refrigerator for up to 30 days but must be kept below 30°C.
It’s important that Mounjaro is kept at a consistent temperature in the fridge because fluctuating temperatures may affect its effectiveness and degrade the active ingredient, tirzepatide. If you’re worried, you might consider using a fridge thermometer to monitor the temperature, but it’s not essential.
You can ensure Mounjaro is kept at the right temperature by:
- storing the pens in their original packaging until their first use
- keeping the pens away from the freezer compartment, if you have one, to avoid freezing
- not storing the pens in the fridge door where the temperature is likely to fluctuate most
How long does Mounjaro last in the fridge?
If stored correctly, Mounjaro can last for up to 24 months in the fridge. However, you should always check the expiry date displayed on the packaging before use.
What happens if I leave Mounjaro out of the fridge?
If Mounjaro is left out of the fridge for more than 30 days, used or unused, the active ingredient may start to break down, losing its effectiveness. That’s why unused pens must be kept in the fridge until their first use and in-use pens should only be left out of the fridge for a maximum of 30 days before you’ll need to safely dispose of them.
Can I put Mounjaro back in the fridge if it reaches room temperature?
Yes, once you have started using your Mounjaro pen you can store it in the fridge. However, you should remove it from the fridge around 15 minutes before injecting it to make sure it’s not too cold. If you inject Mounjaro straight from the fridge, it may be uncomfortable or sting as the medication enters your skin.
I left my Mounjaro out of the fridge overnight, what should I do?
If you have left an unused Mounjaro pen out of the fridge overnight, as long as it has been stored below 30°C, it should still be fine to use because Mounjaro can be kept out of the fridge for up to 30 days. Just put it back in the fridge as soon as you remember.
If it was an unopened Mounjaro pen, you’ll have 30 days to use it before it must be disposed of. So if you can, use the pen when you finish your old pen. You may still be able to use all 4 doses before discarding it but it depends on how many doses you still have in your old pen.
Before using the pen, check the expiry date to make sure it is still within the date and check the medication is clear.
Mounjaro expiration dates: how long does Mounjaro last?
The Mounjaro KwikPen has a shelf life of 24 months, so unused pens can be kept in the refrigerator up until the expiry date.
If you have already started using a Mounjaro pen it must be disposed of after 4 weekly doses and should not be used more than 30 days after its first use.
Where can I find the expiry date on my Mounjaro pen?
The expiry date is printed on the external packaging the Mounjaro KwikPen is supplied in. It is also clearly printed on the pen label as seen in the image below. It is important to check the expiry date on both the box and the pen before first use.
What should my Mounjaro pen look like?
The liquid inside the Mounjaro pen should be colourless to slightly yellow. You can inspect the liquid by looking at the glass vial on the pen.
Do not use the Mounjaro pen if the liquid:
- is cloudy
- is discoloured
- has particles or debris in it
- has been frozen
If the liquid shows any of these signs you should dispose of the pen and get a new one.
Travelling with Mounjaro
If you’re taking Mounjaro and need to travel, there are a few things you’ll need to consider before you go.
- If you are travelling abroad, we recommend that you check the medical regulations of the country you are travelling to. Some countries do not allow certain medications into the country or restrict the amounts allowed within their borders. You might need to show documentation, like a medical certificate, to be allowed to take the medication with you. It’s best to check this before you travel to avoid any delays or confusion.
- Before you travel, ensure you have enough Mounjaro to last for your entire trip.
If you are travelling to a different time zone, you may find it useful to set an alarm to remind you to take your medication at the usual time and on the correct day.
“When you get a Mounjaro prescription with ZAVA, your doctor will also write a letter that details your prescription details and medication dose. This letter can be used when travelling abroad if you need it and is only available to you, through your online patient account, for free. You can also message one of our doctors if you need further advice on travelling with Mounjaro.”
Accreditations: MBChB, BSc
Do I need to keep Mounjaro cold while I travel?
Yes, but only if you are travelling with an unused Mounjaro pen. Unopened Mounjaro pens should be refrigerated between 2 and 8°C to remain effective. However, they can be stored unrefrigerated provided the temperature does not go above 8°C and they are not left out of the fridge for more than 30 days. If this happens, you must throw the pens away.
If you’re only going for 2 weeks and have a used pen that contains enough doses for your holiday, you do not need to keep it cold while travelling, however, it cannot reach more than 30°C.
To store Mounjaro safely on the go, you should:
- travel with unopened Mounjaro in a cool bag, and transfer it into a fridge, if possible, once you reach your destination
- store the pen in its box to protect it from direct sunlight
- avoid storing Mounjaro in a bathroom or cooking area to avoid temperature changes
- make sure in use Mounjaro pens are not stored in direct sunlight and in temperatures above 30°C
If you are travelling for more than 30 days or have any questions about storing Mounjaro safely while you are away, contact your doctor or pharmacist for more advice.
Can I take Mounjaro on a plane?
Yes, you can take Mounjaro on a plane, but it must be stored in your carry-on luggage because the temperatures can fluctuate in the cargo hold causing the medication to freeze, which means it is no longer safe to use.
When you go through security, store your Mounjaro pen and any needles in a clear, plastic bag out of your carry-on luggage, so that it can be clearly seen and identified. If you are unsure or have any specific questions, contact your airline provider for more details.
Frequently Asked Questions
Can I store Mounjaro in a cooler or ice pack?
Yes, you can. However, if you are using an ice pack, keep your medication separate from the ice pack to make sure the medication does not freeze. You could use a cloth or tea towel to wrap the ice pack in.
A cool bag can be useful for storing Mounjaro while you are travelling to your destination to ensure it stays at a consistent temperature.
What happens if Mounjaro freezes?
If Mounjare freezes or has been frozen it will not be usable. If this happens, throw away the pen and start a new one.
How do I safely dispose of Mounjaro?
You should dispose of your used pen needles in a sharps bin as soon as they have been used. Do not throw loose needles into your household rubbish.
When you have finished with the pen, it can be discarded in the sharps bin or in your household bin if you have removed the needle.
If you are no longer using Mounjaro, you should contact your doctor, nurse, or pharmacist about how you should dispose of your unused medications.
What should I do if my Mounjaro has gone bad?
If the liquid in the Mounjaro pen is cloudy, discoloured, has particles in it, or has been frozen, or the pen is damaged or broken you must not use it. Dispose of the pen in the appropriate waste container and get a new one.
Zoe initially studied biological sciences at Aston University, with an integrated placement year working as a mental health care assistant and volunteering abroad. After completing her first degree, she went on to study graduate-entry medicine at Warwick University. After graduating as a doctor, she worked within the West Midlands in Urology, Respiratory Medicine, Infectious Disease, and Psychiatry before transitioning into a full-time medical communications role. Zoe currently works as a freelance medical writer and editor for various health communications agencies, charities, pharmaceutical companies, and health organisations.
Last reviewed: 22 Jan 2025
Sources
- How should the Mounjaro® (tirzepatide) KwikPen® be stored? emc [accessed 20 December 2024]
- How to use Mounjaro, Lilly [accessed 20 December 2024]
- Mounjaro KwikPen 2.5mg solution for injection in pre-filled pen, emc [accessed 20 December 2024]
- Mounjaro KwikPen 2.5mg solution for injection in pre-filled pen User Manual, emc [accessed 20 December 2024]
- Tirzepatide, NICE [accessed 20 December 2024]
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