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How to Store Mounjaro Properly
How to Store Mounjaro Properly
26 October 2026
If you're taking Mounjaro, it's important to know how to store it correctly. In this guide we'll explain what you need to know about Mounjaro storage, so you can use your medication with confidence.
Article Summary:
- Mounjaro’s storage instructions depend on whether your pen’s used (you’ve already taken the first of your 4 weekly doses) or unused (you haven’t yet taken the first of your 4 weekly doses)
- If your pen’s unused, it should be kept refrigerated (between 2-8℃). If it’s used, you can store it either in the fridge (2-8℃) or at room temperature, no hotter than 30℃. It should always be kept away from heat and light, and should never be frozen.
- If you have any questions or concerns about how your medicine’s been stored, it’s best to speak to your clinician or treatment provider. They’ll be able to advise on whether you can continue using your current pen, or whether to discard it and get a new one.
How to store Mounjaro
Mounjaro should be stored according to the instructions provided in your Patient Information Leaflet (PIL). If you’ve chosen treatment with MedExpress, you’ll receive a PIL with every order.
But if you’re just starting out with weight loss treatment, you may have additional questions that the PIL doesn’t cover: how long can Mounjaro be out of the fridge? How long does a Mounjaro pen last? And can I take my treatment with me when I travel?
We want you to feel confident in your care. In this guide, we’ll answer common questions about Mounjaro storage, and what to do when your pen has been stored incorrectly.
| Storing unused Mounjaro pens | Storing used Mounjaro pens | |
|---|---|---|
| What temperature? | 2-8℃ (in a refrigerator) [1] | Either in the fridge (2–8°C), or at room temperature (no hotter than 30°C) [1] |
| For how long? | It should be discarded after 24 months or its expiry date, whichever comes first [2] | It should be discarded after your 4 weekly doses or up to 30 days after its first use, whichever comes first |
| Safety considerations | Keep your pen out of reach of children, and away from heat and direct sunlight | Keep your pen out of reach of children, and away from heat and direct sunlight |
How to store Mounjaro in the fridge
When you receive your treatment, store it in the fridge until its first use.
During manufacturing, storage, packaging and delivery, your treatment is kept at a controlled temperature. This is called a “cold chain”, and it helps keep your treatment safe, stable and effective. Once you receive your treatment, continue this cold chain by storing your unused medication in the fridge.
We recommend you:
- Store your pen in its original packaging, to protect it from light.
- Store your pen away from the cooling element of the fridge. This is because your pen may no longer be safe to use if the treatment freezes. [1]
Once you’ve used your pen for the first time (and it begins its “in-use” period of 30 days), you can either store it in the fridge (between 2–8°C) or at room temperature (up to 30℃). [1] Putting it back in the fridge doesn’t extend this 30-day window. Just be sure to discard it after 4 weekly doses or 30 days after first use, whichever comes first.
If your pen has been stored outside the recommended conditions (we’ll explain what those can be later in this article), don’t use it until you have checked with your treatment provider. Tell them the temperature and how long the pen was exposed, if known.
After each injection, remove the used needle and dispose of it in a sharps bin. Store the pen with its cap on, and without a needle attached.
How long can Mounjaro be left out of the fridge?
Keep your unused pen in the fridge (between 2–8°C) until you start using it. If an unused pen has been left out of the fridge, contact your treatment provider before using it. Tell them how long it was out and, if you know, the temperature it was exposed to.
After first use, your pen can be kept out of the fridge at room temperature (no hotter than 30°C) for the remainder of its 30-day “in-use” period.
Store the pen with its cap on and without a needle attached. Once you’ve finished your 4 weekly doses, you’ll also need to safely dispose of your pen. Remember that while pens can be disposed of in your bin, needles should never be thrown away in regular household waste. You can request a sharps bin from your local council.
What happens if I leave the pen at room temperature?
After your first injection from the pen, you can store it at room temperature as long as:
- The temperature of the room is no hotter than 30°C
- The pen doesn’t freeze
- You keep it away from heat and direct sunlight, and out of sight and reach of children
- You discard it after 4 weekly doses or 30 days after first use, whichever comes first. Never use it after its printed expiry date.
It may be helpful to write down the date you take your first injection, to help you keep track.
What to do if Mounjaro has been stored incorrectly
What you should do depends on how your pen has been stored:
- Frozen: Don’t use a pen that has frozen, even if the medication has thawed.
- Heat or direct sunlight: Don’t use the pen until you’ve checked with your treatment provider. Tell them how hot it became and for how long, if known.
- Time: Discard the pen after 4 weekly doses or 30 days after first use, whichever comes first. Never use it after its printed expiry date, even if it’s unused.
You should also not use your Mounjaro pen if you notice:
- The pen’s damaged
- The medicine’s cloudy, discoloured or has particles in it (it should be clear and colourless to slightly yellow)
It’s important to check your pen for these signs each time you take your treatment.
How to store Mounjaro while travelling
“If you’re planning a trip, you may be wondering how to safely store your medication, both during your journey and when you arrive. We understand it can be a lot to consider, especially for injectable treatments with specific storage requirements like Mounjaro. That’s why we’ve put together a few tips to help you keep your treatment safe.
“Consistently taking your medication each week is one of the best ways to support your long-term progress. However, if you’re worried about travelling with your medication, a short break from treatment won't undo your progress. You can get back on track when you return.”
- Dr. Sophie Dix, Head of Medical Affairs, MedExpress
- Before you travel, check the regulations of your destination country. Different countries have different rules on what types of prescription medication you can bring in. Also be sure to carry the relevant documents (like your prescription).
- If you’re bringing unused pens, ask your healthcare provider about the best way to transport your medication for the duration of the journey. Remember to put it in a refrigerator as soon as you reach your destination.
- If you’re bringing a partially used pen, refrigeration’s optional. However, don’t allow your pen to freeze, or expose it to temperatures above 30℃.
- Check your departure airport’s current screening requirements before you travel. You may need to remove your medication from your carry-on luggage when you pass through security.
- Keep your medication in its original packaging, to protect it from light and support its authenticity.
- Keep your medication in your carry-on bag, and don’t check it in as hold luggage. This is because hold luggage may be exposed to temperature fluctuations which could affect your medication.
- Make sure you take enough medication to last your entire trip, as you may not be able to access more while you’re away.
Storage situations
| Scenario | Action to be taken |
|---|---|
| Left out of fridge overnight | If your pen: 1. Has already been used 2. Wasn’t exposed to temperatures more than 30°C 3. Didn’t freeze, and Was protected from heat and light you can continue using it within its original 30-day window. You may return it to the fridge, but this doesn’t extend the window. [3] Unused pens should be kept between 2–8°C. Contact your treatment provider before using it, and tell them how long it was out and the temperature, if known. [3] |
| Frozen Mounjaro pen | If your Mounjaro pen freezes, you must discard it (according to the instructions provided by your healthcare provider). Don’t attempt to defrost and use it. |
| Exposed to heat | If your Mounjaro pen is exposed to heat above 30℃ (for example, near a radiator or in strong, direct sunlight), check with your treatment provider before using it. Tell them how hot it became and for how long, if known. Even if it looks normal, it may no longer be suitable to use. |
| Past the expiry date | Never use an expired Mounjaro pen, even if it’s been stored properly. You can find the expiry date on the pen label and on the carton, after “EXP”. The expiry date is the last day of that month. [1] |
| Left Mounjaro pen in the car | If you can’t be sure your pen stayed within the recommended storage conditions, don't use it until you’ve checked with your treatment provider. If it’s frozen, or there’s a chance it froze, don’t use it. |
At first, the storage instructions for Mounjaro may seem like a lot to process. But as you get used to treatment, you’ll soon get into the rhythm of safely storing both your unused and used pens.
At MedExpress, we offer online consultations with regular clinical check-ins and a range of weight loss treatments including Mounjaro, Wegovy Pen, Wegovy Pill and Foundayo. Our team can help you find the right treatment for you.
References
- Package leaflet: Information for the patient Mounjaro ® 2.5 MG KwikPen ® solution for injection in pre-filled pen Mounjaro ® 5 MG KwikPen ® solution for injection in pre-filled pen Mounjaro ® 7.5 mg KwikPen ® solution for injection in pre-filled pen Mounjaro ® 10 mg KwikPen ® solution for injection in pre-filled pen Mounjaro ® 12.5 mg KwikPen ® solution for injection in pre-filled pen Mounjaro ® 15 MG KwikPen ® solution for injection in pre [Internet]. [cited 2026 Oct 20]. Available from: https://www.medicines.org.uk/emc/files/pil.15481.pdf
- Mounjaro KwikPen 2.5MG, 5mg, 7.5mg, 10mg, 12.5mg, 15mg solution for injection in pre filled pen - summary of product characteristics (SmPC) - (EMC) | 15481 [Internet]. Medicines.org.uk. 2025 [cited 2026 Oct 21]. Available from: https://www.medicines.org.uk/emc/product/15481/smpc
- How should the mounjaro® (tirzepatide) KwikPen® be stored? [Internet]. Lilly.com. 2025 [cited 2026 Oct 20]. Available from: https://medical.lilly.com/uk/products/answers/how-should-the-mounjaro-tirzepatide-kwikpen-be-stored-217607
Next scheduled review date: 26 October 2029
Authors
Written by: Dr. Zoë Lees (PhD)
Dr. Zoë Lees is a medical writer at MedExpress specialising in obesity and health communication. She completed her PhD at the University of Glasgow, where she investigated adipose tissue (fat tissue) function in pregnancies complicated by pre-eclampsia and gestational diabetes. Her work focuses on translating complex clinical evidence into clear, engaging and evidence-based health information for patients and the public. At MedExpress, Zoë contributes to clinical content, educational resources and media communications across areas including weight management, GLP-1 therapies and metabolic disease. Zoë is particularly interested in improving public understanding of obesity as a chronic condition and ensuring patients have access to accurate, accessible health information grounded in current scientific evidence.
Medically reviewed by: Dr. Sophie Dix (BSc, PhD)
Dr. Sophie Dix is Head of Medical Affairs at MedExpress. A behavioural neuroscientist by training, Sophie has spent 30 years working at the intersection of medical research, pharmacology, technology and patient communication across the pharmaceutical industry, health technology and charity sectors. At MedExpress, Sophie's role is to ensure that everything the organisation does is grounded in the most current science. That means translating complex clinical evidence into accessible health information across the website, clinical pathways and media communications. It also means working with external press and broadcast media as a named expert commentator, making the science behind weight management and GLP-1 treatments understandable to a general audience. A core part of Sophie's work is building MedExpress's Real-World Evidence (RWE) programme: learning systematically from patient outcomes to understand what works in practice, not just in clinical trials. This patient-level insight feeds directly into improving patient experience and health outcomes. Sophie believes that patients make better decisions when they have access to accurate, evidence-based information. As an advocate for meaningful change in how obesity is understood, Sophie works to reduce stigma and raise awareness of the condition as an illness. This includes reframing the conversation around GLP-1s from aesthetics to public health, while highlighting the health benefits of weight loss and weight management.
Note from the experts
Remember: This blog shouldn’t be regarded as medical advice, diagnosis, or treatment. We make sure everything we publish is fact checked by clinical experts and regularly reviewed, but it may not always reflect the most recent health guidelines. Always speak to your doctor about any health concerns you have.
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