Short answer: Before first use, weight-loss injection pens should be kept in the refrigerator at 2°C–8°C (36°F–46°F), protected from light. They must never be frozen. Pens in use can be kept at room temperature below 30 °C (86 °F) for a limited time: from 21 days to 8 weeks, depending on the product and pen type. The leaflet of your own pen is what counts.

Key takeaways

  • Unopened pens are stored in the refrigerator between 2–8 °C (36–46 °F); they never go in the freezer.
  • A frozen pen must never be used, even after it thaws, because the structure of the active ingredient is damaged.
  • When traveling, use insulated cooler bags, and never put pens in checked baggage on a plane.
  • Always keep the pen cap on to block light exposure.

GLP-1 injections are stored in the refrigerator, between 2–8 °C (36–46 °F), and protected from light. They are never frozen; a frozen pen is not used even after it thaws. Once in use, there is a period during which a pen can stay at room temperature, and that period varies by product.

This page is for general information only. Storage times can differ by country and packaging; the definitive information is in the package leaflet in your own box. When in doubt, ask your pharmacist.

Storing in the refrigerator

  • The temperature should be between 2–8 °C (36–46 °F).
  • Keep the pen in its original box; the box protects it from light.
  • It does not go in the freezer compartment or the freezer. Shelves that touch the back wall of the refrigerator carry a risk of freezing.
  • The shelves inside the door have the most temperature fluctuation; a middle shelf is safer.

How long can it stay at room temperature?

A pen in use can be kept at room temperature for a certain period (usually as long as it does not exceed 30 °C, or 86 °F). This period varies by product and pen type. The values in the EMA product information are:

  • Mounjaro KwikPen (multi-dose pen): after first use, 30 days below 30 °C (86 °F); after that it is thrown away even if not used up.
  • Mounjaro single-dose pen or vial: may be kept out of the refrigerator below 30 °C (86 °F) for up to 21 days in total; after that it is thrown away.
  • Ozempic: after first use, 6 weeks (4-dose pens) or 8 weeks (8-dose 0.5 mg and 1 mg pens), below 30 °C (86 °F) or in the refrigerator.
  • Wegovy FlexTouch: after first use, 6 weeks below 30 °C (86 °F) or in the refrigerator.
  • Wegovy single-dose pen: may be kept out of the refrigerator below 30 °C (86 °F) for up to 28 days.

Once a pen has been taken to room temperature, the clock starts; putting it back in the refrigerator does not reset it. Writing the date you took it out to room temperature on the pen is far more reliable than trying to remember later.

How do you travel with it?

  • On a plane, carry it in your hand luggage. The cargo hold carries a risk of freezing.
  • A cooler bag can be used, but the ice pack should not touch the pen directly. Contact causes freezing.
  • Do not leave it in a car; in a closed car, the temperature quickly goes well above 30 °C (86 °F).
  • Keeping your prescription or a doctor's note with you makes security checks easier.

When should it not be used?

Do not use a pen whose contents are cloudy, discolored or contain particles. Products you suspect have been frozen, know have been kept at high temperatures, or are past their expiration date are also not used. In these cases, ask your pharmacist.

Pen tracking

Haftra keeps track of the pen you have and the number of doses left, and shows whether you have a spare pen. That way, you see when you need to go to the pharmacy from the app, not by looking at the pen. It is free and can be used without an account.

iPhone, iPad and Apple Watch. Free.

Frequently asked questions

At what temperature are weight-loss injections stored in the refrigerator?

The temperature should be between 2–8 °C (36–46 °F). Keep the pen in its original box; the box protects it from light. It does not go in the freezer compartment or the freezer.

How long can it stay at room temperature?

It depends on the product and pen type, from 21 days to 8 weeks. Mounjaro KwikPen: 30 days below 30 °C (86 °F) after first use. Mounjaro single-dose pen or vial: up to 21 days in total out of the refrigerator below 30 °C (86 °F). Ozempic: 6 or 8 weeks after first use depending on the pen. Wegovy FlexTouch: 6 weeks after first use; Wegovy single-dose pen: up to 28 days out of the refrigerator. The leaflet of your own pen is what counts.

If I put it back in the refrigerator, does the clock reset?

Once a pen has been taken to room temperature, the clock starts; putting it back in the refrigerator does not reset it.

What should you do if the pen freezes?

Do not use it, even after it thaws, because the structure of the active ingredient is damaged. Discard it as medical waste and ask your pharmacist if you are unsure.

How do you carry it on a plane?

Carry it in your hand luggage, not in checked baggage; the cargo hold carries a risk of freezing. A cooler bag can be used, but the ice pack should not touch the pen directly. Keeping your prescription with you makes security checks easier.

Sources

  • EMA - Mounjaro (tirzepatide)
  • EMA - Ozempic (semaglutide)
  • EMA - Wegovy (semaglutide)
  • NHS - Obesity treatment
  • U.S. Food and Drug Administration (FDA)

Last reviewed: August 4, 2026