How to Store and Travel With Weight Loss Injections
Last updated: 8 August 2026
TL;DR: Store unopened weight loss injection pens in the fridge at 2–8°C and never freeze them. Once in use, pens can be kept at room temperature (below 30°C) for a set number of days that varies by product, so always follow your pen's patient information leaflet. For travel, carry pens in hand luggage with a cool pack and keep your prescription details to hand.
Storing a weight loss injection correctly protects its effectiveness, and getting it wrong, especially freezing or overheating, can make a pen unusable. This guide covers home storage, how long a pen lasts out of the fridge, and how to travel with it. Always defer to the patient information leaflet supplied with your specific product, as in-use limits differ between medicines.
How Should You Store Weight Loss Injections at Home?
Unopened pens should be kept in the fridge at 2–8°C, in their original packaging, away from the freezer compartment. According to the manufacturer patient information leaflets for products including Mounjaro and Wegovy, freezing damages the medicine and a frozen pen must not be used.
Keep pens away from direct heat and light, and do not store them in the fridge door where temperature fluctuates most. If your fridge runs very cold, position pens toward the middle shelves to avoid accidental freezing, which is a more common problem than overheating at home.
How Long Can a Pen Stay Out of the Fridge?
Once in use or unavoidably out of the fridge, pens can be kept at room temperature below 30°C for a limited period that depends on the product. The number of days differs between medicines, so the leaflet is the authority.
| Product | Before first use | In-use / room temperature (below 30°C) |
|---|---|---|
| Mounjaro (tirzepatide) | Fridge 2–8°C; do not freeze | Up to 30°C for a limited number of days per the leaflet |
| Wegovy (semaglutide) | Fridge 2–8°C; do not freeze | Up to 30°C for a limited number of days per the leaflet |
| Ozempic (semaglutide) | Fridge 2–8°C; do not freeze | Up to 30°C for a limited number of days per the leaflet |
Because these windows differ and are occasionally updated, check the current patient information leaflet for your exact product rather than relying on a general figure. Note the date a pen first leaves the fridge, and count the in-use days from then, not from your first injection.
How Do You Travel With Weight Loss Medication?
Carry pens in your hand luggage, never in checked baggage, because the hold can freeze and freezing ruins the medicine. Use an insulated bag or a cool pack (not directly against the pen, to avoid freezing it) to keep pens cool on longer journeys.
- Keep pens in original packaging with the leaflet.
- Carry a copy of your prescription or a letter from your pharmacy or prescriber.
- Pack needles separately as advised, with the same documentation.
- Plan fridge access at your destination for pens you are not currently using.
For most trips within a pen's room-temperature window, a cool bag is enough; for longer stays, arrange refrigeration on arrival.
What Are the Rules for Flying With Injections?
Medicines and the equipment to administer them are permitted in hand luggage on UK flights, and injectable medicines with needles are allowed when accompanied by supporting documentation. Carrying a prescription or a pharmacy letter smooths security checks.
Liquid medicine allowances are more generous than the standard 100ml limit when the medicine is essential, but you should declare it at security and have documentation ready. Rules can vary by airline and country, so check your airline's guidance and the destination's requirements before you fly, and keep a cool pack that complies with security rules.
What Should You Do If Your Medication Gets Too Warm or Frozen?
If a pen has frozen, do not use it, even after thawing, because freezing damages the medicine irreversibly. If a pen has been above 30°C or out of the fridge beyond its in-use window, its effectiveness may be reduced.
When in doubt, do not inject; contact your pharmacy or prescriber for advice on whether the pen is still safe to use and how to obtain a replacement. It is safer to check than to inject a pen that may have been compromised. A pharmacist can advise quickly on next steps.
Related Guides
- Staying on Track During Holidays and Travel on GLP-1 Medication
- How to Manage Common GLP-1 Side Effects: A Practical Patient Guide
- GLP-1 Maintenance Dosing: What Happens After You Reach Your Goal
- How Bolt Prescribes: Our Clinical Process
Key Takeaways
- Store unopened pens in the fridge at 2–8°C and never freeze them.
- A frozen pen must not be used, even after thawing.
- In-use room-temperature limits (below 30°C) vary by product; follow the leaflet.
- Note the date a pen first leaves the fridge and count in-use days from then.
- Travel with pens in hand luggage with a cool pack and your prescription details.
- If a pen overheats or freezes, do not inject; check with your pharmacy first.
Frequently Asked Questions
Can Mounjaro be left out of the fridge?
Yes, for a limited time. Once in use, pens can be kept at room temperature below 30°C for a set number of days that varies by product, so follow your pen's patient information leaflet. Note the date it first leaves the fridge and count the in-use days from then.
Does Wegovy need to be refrigerated?
Unopened Wegovy should be stored in the fridge at 2–8°C and never frozen. Once in use it can be kept at room temperature below 30°C for a limited period stated in the leaflet. Keep it out of direct heat and light.
Can I take weight loss injections on a plane?
Yes. Carry pens in hand luggage, not checked baggage, because the hold can freeze them. Injectable medicines and needles are permitted with supporting documentation such as a prescription or pharmacy letter. Check your airline and destination rules before flying.
What should I do if my pen freezes or overheats?
Do not use a pen that has frozen, even after thawing, as freezing damages it permanently. If a pen has been too warm or out of the fridge beyond its in-use window, do not inject and contact your pharmacy or prescriber to check whether it is still safe and arrange a replacement.
Published by Bolt Pharmacy, a GPhC-registered UK pharmacy. Sources: manufacturer Summaries of Product Characteristics and patient information leaflets for Mounjaro, Wegovy and Ozempic (electronic medicines compendium); MHRA product information; UK Civil Aviation Authority and airport security guidance on travelling with medicines. Storage limits vary by product and may be updated; always follow the leaflet supplied with your medicine. Reflects published information as of August 2026.
