How to Store Weight Loss Injections

Storing your weight loss injections correctly is essential, but it doesn't need to be complicated. Once you know a few basic rules, it's easy to fit into your routine at home, at work or on vacation. Let’s explore how to store your pen and how to make sure it's safe to use.

Article summary

• Keep new, unused pens in the fridge at 2°C to 8°C. Never freeze them.
• Once you've started a pen, most can be kept below 30°C for a set time. This is between 28 days and 8 weeks, depending on your pen.
• Keep your pen away from heat, direct sunlight and freezing cold, and always carry it in your hand luggage when you fly.

Why does weight loss injection storage matter?

Weight loss injections can be affected by temperature. If a pen gets too hot, freezes, or sits in direct sunlight, the medicine may be damaged [1]. Storing your pen properly helps make sure that your weight loss medicine is safe to use.

Every medication has its own instructions, so always read the leaflet that comes with your pen. Most weight loss injections share the same rules.

Weight loss injection storage rules

• Store unused pens in the fridge. Keep them between 2°C and 8°C [1].
• Don't freeze your pen. If a pen has been frozen, don't use it, even if it has thawed [1].
• Keep it away from the back of the fridge. The cooling part of the fridge can be cold enough to freeze it [1].
• Keep the cap on. This protects the medicine from light [1].
• Avoid heat. Don't leave your pen in a car or anywhere that can get too hot or too cold [1].
• Check the time limit. Once a pen is out of the fridge, it can only be used for a set number of days [1].

How long can your pen stay out of the fridge?

All weight loss injections should be kept in the fridge before you first use them. After first use, some pens can be stored outside of the fridge for a set amount of time as long as they aren’t exposed to extreme temperatures. The rules around storing your pen after first use will depend on which pen you’ve been prescribed.

Not sure which type of pen you have? Check the leaflet in the box, or ask your pharmacist or our Clinical team.

How to store weight loss injections in summer

Canadian summers can get hot, especially inside a parked car. Temperatures inside one can quickly go above 30°C, even on a mild day.

To keep your pen safe in warmer weather:

• Never leave your pen in a car, even for a short time. [1]
• Keep it out of direct sunlight. [1]
• Make sure the ice pack doesn't touch the pen directly. This could make it too cold and at risk of freezing. [2]

If you're heading away to a hot climate, you might find our guide on how weight loss is changing the way Canadians travel helpful.

How to store weight loss injections in winter

Cold weather can be just as risky as heat when it comes to storing your weight loss medication. If your pen freezes, you'll need to throw it away [1]. Here’s our advice.

• Don't leave your pen in a car overnight or in an unheated garage [1].
• When you're outside in the cold, keep your pen close to your body, under your clothes [2].
• Don't store it near a window or door that lets in freezing air.

Travelling with weight loss injections

Travelling with your pen is usually straightforward with a little planning.

• Pack it in your hand luggage. Never put it in checked bags. The hold on a plane isn't temperature controlled, so your pen could freeze [2].
• Use a cooler bag. An insulated bag or travel cooling pouch helps keep your pen at the right temperature [2].
• Tell airport security. Let them know you're carrying medication and needles [3].
• Keep it in the original box. This helps protect it from light and shows it's been prescribed to you.
• Check the fridge when you arrive. If your hotel room or accommodation has a fridge, put your unused pens in it. Keep them away from the back of the fridge, where it's coldest [1].

For more tips, read our guide to flying with weight loss medication.

What to do if your pen gets too hot or too cold

Accidents happen. If you think your pen hasn't been stored properly, here's what to do.

1. Don't use it if it's been frozen. This applies even if it's thawed out [1].
2. Check the liquid. It should be clear and colourless. Don't use it if it looks cloudy, has changed colour, or has bits in it [1].
3. Check how long it's been out of the fridge. If it's past the time limit for your pen, throw it away [1].
4. Ask for advice. If you're not sure whether your pen is safe to use, speak to your pharmacist or our Clinical team before you inject.
5. Throw used pens away safely. Put them in a sharps container. Do not dispose of them with your household garbage [1].

Storing your pen well is one part of using your treatment safely. It also helps to know what's normal once you start. Read more about weight loss injection side effects and how to manage them.

Frequently asked questions

Do weight loss injections need to be kept in the fridge?

Unused pens should be kept in the fridge at 2°C to 8°C. Once you've started a pen, most can be kept at room temperature below 30°C for a set time. This is between 28 days and 8 weeks, depending on your pen [1].

How long can a weight loss injection stay out of the fridge?

That depends on your pen. Single-use pens can stay below 30°C for up to 28 days in total [1]. Multi-dose pens can be kept out of the fridge for up to 30 days [3] or up to 8 weeks [1] once you've started them. Your patient information leaflet will tell you which applies to you.

Can I use my pen if it's been frozen?

No. If your pen has been frozen, throw it away and use a new one [1].

Can I take my weight loss injection on a plane?

Yes. Keep it in your hand luggage, not your checked bags, and tell security you're carrying it [3].

How do I know if my pen has been damaged?

Look at the liquid before you inject. It should be clear and colourless. If it looks cloudy, has changed colour or has bits in it, don't use it [1].

Proper weight loss injection storage comes down to a few habits. Keep new pens in the fridge, never let them freeze, and protect them from heat and light. Once you've started a pen, check how long it can stay out of the fridge and stick to that limit.

If you've got questions about your treatment, our Clinical team is here to help.

Find out what treatment is suitable for you with MedExpress.

References

1. Novo Nordisk Canada Inc. Wegovy (semaglutide injection) product monograph: patient medication information [Internet]. Mississauga (ON): Novo Nordisk Canada Inc.; 2025 Dec 10. Available from: https://www.novonordisk.ca/content/dam/nncorp/ca/en/products/wegovy/consumer-information/wegovy-en-ci-10-december-2025.pdf
2. Nova Scotia Health. Travelling with diabetes: patient and family guide [Internet]. Halifax (NS): Nova Scotia Health; 2026 Available from: https://www.nshealth.ca/sites/default/files/documents/2646-2026.08.05.pdf
3. Eli Lilly Canada Inc. Travelling with Mounjaro KwikPen [Internet]. Toronto (ON): Eli Lilly Canada Inc. Available from: https://www.lilly.com/en-ca/medicines/medicine-faqs/mounjaro-kwikpen/travelling-with-mounjaro