Storing your injection pen correctly is essential for the medication to work as intended. GLP-1 medicines such as Wegovy, Ozempic and Mounjaro are biological drugs — they can degrade if exposed to the wrong temperature, direct sunlight or freezing. This guide gives you a clear overview of everything you need to know about storage, whether you are at home or travelling.
Unopened pens: always in the fridge
Pens you have not yet used must be stored in the refrigerator at 2–8 °C. This is a standard fridge temperature. A few important points:
- Place the pen in the middle of the fridge — not in the door (too many temperature swings) and not pressed against the back wall (risk of freezing).
- Never freeze an unopened pen. A frozen pen is ruined and must not be used — the medication loses its potency, and you may notice the liquid looks different from usual.
- Protect from light — keep the pen in its original carton until you are ready to use it.
- Always check the expiry date before starting a new pen.
Opened pens: how long do they last?
Once you have taken your first injection, the storage rules change. An opened pen does not necessarily need to be kept in the fridge, but its shelf life is limited. Here are the current guidelines by product:
| Product | Shelf life after opening | Max. temperature |
|---|---|---|
| Ozempic (semaglutide) | Up to 6 weeks (42 days) | 30 °C |
| Wegovy (semaglutide) | Up to 6 weeks (42 days) | 30 °C |
| Mounjaro (tirzepatide) | Up to 30 days | 30 °C |
Ozempic and Wegovy can be stored in the fridge (2–8 °C) or at room temperature within the shelf-life period. Mounjaro, however, must be stored unrefrigerated (max. 30 °C) after first use — as stated in the approved SmPC. Always check the current package leaflet, as recommendations may be updated.
Especially important for dose-splitting
If you practise dose-splitting — using one pen for multiple doses over several weeks — the shelf life is particularly critical. Even though a Wegovy 2.4 mg pen theoretically contains many doses, it is only stable for 42 days (6 weeks) after the first injection. You can therefore use it for a maximum of 6 weekly doses, regardless of how many clicks remain.
Write the date of first use directly on the pen with a permanent marker so you always know when it expires.
What you must never do
- Freeze a pen — whether unopened or in use. A pen that has been frozen must be discarded.
- Re-freeze — a pen that has been at room temperature must not be put back in the freezer.
- Expose to direct sun or heat — never leave the pen in a sunny spot, a hot car, or near a radiator.
- Shake the pen — GLP-1 solutions are delicate. Do not shake the pen before injecting.
Check the medication before injecting
Before each injection, always inspect the solution in the pen. GLP-1 medication should normally be clear and colourless. Do not use the pen if you notice:
- Cloudiness or a hazy appearance
- Discolouration (e.g. a yellow or brown tint)
- Visible particles or floating matter
If in doubt, contact your pharmacist.
Storage when travelling
When travelling with your pen, the room-temperature rules above apply — but there are a few extra precautions:
Flying
- Always carry the pen in your hand luggage — never in checked baggage. The cargo hold can reach temperatures well below freezing, which would ruin your medication.
- Airport security generally allows injection pens with a prescription. Carry a copy of your prescription or a letter from your doctor, especially when travelling abroad.
- Insulated travel cases such as FRIO pouches keep pens cool without electricity or ice and are ideal for air travel.
Car and holiday accommodation
- A car parked in the sun can reach over 50 °C inside. Never leave the pen in the car.
- If you have no access to a fridge, a FRIO cooling pouch or a small cooler with ice packs will work — make sure the temperature does not drop below 2 °C (avoid direct contact with ice).
Hot climates and summer heat
- In a country with high ambient temperatures, prioritise storing the pen in a fridge even if it is already opened — room temperature can quickly exceed 30 °C.
- Carry the pen in an inside pocket close to your body rather than in a bag left in direct sunlight.
What to do if the pen has been stored incorrectly
If you are unsure whether the pen has been too warm, too cold or has expired, the golden rule is: do not use it. Contact your doctor or pharmacist. Degraded GLP-1 medication can look normal but may have reduced or no effect — and you risk going a week without correct treatment.
Disposing of used pens
Used pens and needles are clinical waste and must not be placed in household rubbish. Return them to your pharmacy or use an approved sharps container. Most pharmacies accept used sharps free of charge.
Quick-reference summary
| Situation | What to do |
|---|---|
| Unopened pen | Fridge 2–8 °C, original carton, never freeze |
| Opened pen at home | Fridge or room temperature (max. 30 °C) |
| Opened pen while travelling | FRIO pouch or cooler, hand luggage on planes |
| Pen has been frozen | Discard it, contact pharmacy |
| Pen looks cloudy/discoloured | Do not use, contact pharmacy |