So: you’ve done your research, chosen Mounjaro to help you on your weight loss journey, and your first doses have arrived after your clinician has confirmed it's suitable for you.
You may have already factored in needing to set aside time to inject on the same day every week as part of your new routine. As Mounjaro comes in liquid-form, single-dose prefilled pens, an equally important first step is planning how to store and dispose of them safely. This is especially vital if you have young children, pets, or a vulnerable person living with you.
Properly storing Mounjaro is also key to keeping your medication fresh and working effectively. It’s easier than you think and you don’t need any fancy equipment, but you do need to keep an eye on a few important details to ensure you’re using Mounjaro safely.
Read on to understand how to store Mounjaro, what to do if it expires, how to take Mounjaro travelling, and how to dispose of your medication at home or on the go.

How to store Mounjaro pens?
For Mounjaro to work properly, you need to ensure your pens are stored correctly. If you’ve ordered Mounjaro from an online provider like Voy, it will be delivered to you in temperature-controlled packaging.
How to store unused pens
To store your unopened Mounjaro pens:
- Keep them in the fridge between 2 and 8 degrees °C.
- Store them in the original, unopened packaging which clearly displays their use-by date
- Don’t store Mounjaro pens in the fridge door as this is where the temperature is most likely to fluctuate.
- Don't freeze Mounjaro pens—if they become frozen, throw them away.
How to store Mounjaro you’re using
Once you’ve opened a Mounjaro pen, you should store it:
- In the fridge between 2 and 8°C. Or unrefrigerated for up to 30 days, as long as the temperature doesn’t go above 30°C.
- Away from heat and out of sight and reach of children or vulnerable adults.
Before using your Mounjaro pen, check that:
- It’s in date (you can find the expiration date on the label).
- The needle is not damaged.
- The medicine isn’t cloudy, discoloured, or has particles in it.
Some people prefer to get a dedicated mini fridge for medication to keep it at the right temperature and free from contamination. But if that’s not feasible for you, don’t sweat it. Storing Mounjaro in your main fridge is fine.
If you keep Mounjaro in your main refrigerator, it’s a good idea to keep it away from food, so there’s less risk of spillages that could spoil your pens or vials and make them unusable. You should also avoid keeping it in the fridge door, as this is where the temperature changes the most, or at the back of the fridge where there’s a risk of it getting too cold and freezing (we’ll get into why this is bad in a moment).
Remember: always store Mounjaro out of reach of under-18s, or any other vulnerable person that may live with you.
Mounjaro storage do’s and don’ts
How long can Mounjaro be kept in the fridge?
Unopened Mounjaro generally lasts up to 24 months in the fridge if it’s stored correctly. But always make sure to check the expiration date on the packaging.
How long can Mounjaro be out of the fridge?
If you’re in the UK, Mounjaro pens can be stored at room temperature (up to 30°C), but only for 30 days—even if it’s still in date. So if you’ve left your Mounjaro out of the fridge overnight, there’s no need to worry.
Always keep your Mounjaro pens in a cool, dry place, in the original box and out of direct sunlight. If you take your medication out of the fridge, set a 30-day reminder on your phone so you don’t accidentally use any doses past this date.
What happens to Mounjaro if I leave it out of the fridge?
Leaving Mounjaro out of the fridge for longer than the recommended time (30 days in the UK) will cause it to be less effective because the medication will start to break down and deteriorate, so safety and sterility can’t be guaranteed.
Extreme heat or freezing temperatures from improper storage can also affect the quality and effectiveness of your medication. Plus, steam from the shower can cause condensation on your Mounjaro pens, so be mindful not to store them in a bathroom cabinet.
What do to if Mounjaro has not been stored correctly
Concerned your Mounjaro hasn’t been stored correctly? Here’s what to do.
If it’s been exposed to extreme temperatures
If Mounjaro has been exposed to temperatures over 30°C or frozen, it might be unsafe to use. Dispose of the medicine if you think this might have happened.
If it’s been kept out of the fridge
If it’s been kept at room temperature for more than 30 days, it should also be discarded.
If it’s changed colour or looks cloudy
Mounjaro should be colourless to slightly yellow. Discard the pen if it has particles, or is cloudy or discoloured.
How to dispose of Mounjaro
It’s important to know how to dispose of Mounjaro safely. As there are needles involved, you can’t throw loose pens into your household waste.
Once your pre-filled pen has been used, it’s time to throw it out. Don’t reuse your needle or share it with anyone else. Some pens can be used for four doses with a fresh needle each time before throwing the pen away. In this case, there will be an indicator of how many doses are left. If in doubt, always check the instructions on the information leaflet or packaging your Mounjaro came in.
You’ll need a sharps bin to discard your medication properly—never dispose of Mounjaro in your household bin. If you order from Voy, we’ll ensure a sharps bin is delivered alongside your medication, and once full you can contact your local council to collect this from your home.
Travelling with Mounjaro
When you’re off on holiday, medication is the last thing you want to be worrying about. Travelling with Mounjaro is easy as it can be out of the fridge for up to 30 days, which makes it more travel-friendly than some medications. As Mounjaro is taken once a week, you’ll usually be able to use it before the 30-day expiration, unless you’re away for a long time or you miss a dose.
If you’re travelling with Mounjaro you should take it in your carry-on bag. Keeping it in your checked-in luggage may not only risk it getting squashed and damaged, but the temperature of the plane’s luggage storage might be too cold to safely store your Mounjaro.
If you’re worried about it getting too hot or cold while travelling, invest in a mini cooler bag to keep Mounjaro at a steady, cool temperature.
Always remember to check your airline’s restrictions for taking prescribed medication on a flight, as well as the customs regulations of your destination. We recommend bringing any prescription medication in its original packaging containing the patient information leaflet, or a copy of the prescription.
Sticking to a new medication routine can be hard to get used to, but hopefully, we’ve reassured you that Mounjaro’s storage specifications won’t disrupt your day to day, even if you’re on the go. If you have more questions about Mounjaro that aren’t answered in this article, check out our Mounjaro FAQs for more advice.
Wondering if Voy’s weight loss programme is right for you? Take our quiz to find out if it’s what you might be looking for—it only takes a few minutes.