Storage matters. GLP-1 medicines are biological injectables and are sensitive to temperature. Get the basics right and you protect both the dose and your money.
Standard storage
Before you start a pen, keep it in the fridge at 2 to 8°C, away from the cooling element. Never freeze it, and keep it in its carton, or with the cap on, to protect it from light. How long a pen keeps once you start it is different for each pen, and it is printed in the leaflet in the box.
Out of the fridge
From the patient leaflets (checked September 2026): once in use, a Mounjaro KwikPen can be kept out of the fridge, not above 30°C, for up to 30 days, and then it must be thrown away, even if medicine is left in it. A Wegovy FlexTouch pen (0.25mg to 2.4mg) keeps for 6 weeks once in use, below 30°C or in the fridge, with the cap on. The Wegovy 7.2mg single-dose pen can be kept out of the fridge for up to 28 days, not above 30°C. The time does not start again if you put a pen back in the fridge.
| Mounjaro | Wegovy | |
|---|---|---|
| Fridge storage | 2°C to 8°C, protected from light | 2°C to 8°C, protected from light |
| How long a pen keeps once in use | Up to 30 days out of the fridge, then throw it away | 0.25mg to 2.4mg pens: 6 weeks, out of the fridge or in it. 7.2mg pen: up to 28 days out of the fridge |
| Highest temperature out of the fridge | Not above 30°C | Below 30°C (7.2mg pen: not above 30°C) |
| Once the limit is reached | Discard the pen | Discard the pen |
If it's been frozen
Discard it. Do not use, even if it thawed and looks normal. Freezing damages the peptide and you cannot rely on the dose to work.
If it's been left out too long
Don't guess. Contact your pharmacist with how long the pen was out and at what temperature. They can advise whether it's still safe to use or should be replaced.
Travelling with your pens
- Carry in hand luggage, never hold luggage: hold temperatures can freeze it.
- Use a cool bag with a gel pack, rather than direct ice contact.
- Carry your pharmacy label or prescription, and a supporting letter if flying.
- Check the medicines rules for your destination country before you travel.
- Plan for refrigeration at the other end: a mini-fridge or hotel fridge that's actually cold.
- Take a sharps bin, or arrange disposal at your destination.
Sharps disposal
Used needles must be disposed of safely in a sharps bin, never in household rubbish. When your bin is full, seal it and arrange disposal through your GP practice or your local council's sharps collection service.
The patient information leaflet supplied with your pen is the definitive source for storage limits. If a figure online disagrees with your leaflet, follow the leaflet.
See also how to inject Mounjaro and the Mounjaro dosage chart.