Keep an unopened weight loss pen in the fridge between 2°C and 8°C. Once out of the fridge, it can be kept for a limited period below 30°C. The number of days differs by medication and pen type, so follow the leaflet supplied with your pen. In the UAE, keeping the pen below 30°C is often the harder limit, because a car interior exceeds it quickly. Never freeze a pen, or use one that has frozen.
- Keep unopened pens in the fridge between 2°C and 8°C, in the original carton to protect them from light, and never freeze them.
- The FDA prescribing information for Mounjaro states that a single-dose pen can be stored unrefrigerated at temperatures not exceeding 30°C for up to 21 days.
- Lilly UK states that the multi-dose Mounjaro KwikPen can be kept at up to 30°C for 30 days after first use; the US and UK figures apply to different pens, so follow the leaflet supplied with your pen in the UAE.
- Novo Nordisk states that an unopened Wegovy pen can be kept between 8°C and 30°C for up to 28 days, and the FDA label for Ozempic allows 56 days at 15°C to 30°C after first use.
- In a UAE summer, keeping a pen below 30°C is often harder than staying within the day count, so never leave a pen in a car, on a windowsill or in direct sunlight.
- Whether a pen can go back in the fridge after being kept at room temperature also differs by product, so follow your leaflet and contact the clinic if unsure.
Each storage figure on this page comes from the official product information for that injection.
How long can your pen stay out of the fridge?
The figures below come from the official product information and apply to the pen types named. The US single-dose figure and the UK multi-dose figure are not interchangeable. The leaflet supplied with your own pen is the one to follow, because presentations differ between products and markets.
| Medication and pen | In the fridge | Out of the fridge | Source |
|---|---|---|---|
| Mounjaro single-dose pen or vial | 2°C to 8°C, in the carton | Up to 21 days at not more than 30°C | FDA prescribing information, January 2026 |
| Mounjaro KwikPen (multi-dose), after first use | 2°C to 8°C before first use | Up to 30 days at up to 30°C after first use | Lilly UK medical information, May 2026 |
| Wegovy pen, before the cap is removed | 2°C to 8°C, in the carton | Up to 28 days between 8°C and 30°C | Novo Nordisk, wegovy.com |
| Ozempic pen, after first use | 2°C to 8°C before first use | Up to 56 days at 15°C to 30°C, or in the fridge | FDA prescribing information, January 2025 |
Every row shares one limit, 30°C, and every day count assumes the temperature never exceeds it.
Why will you see two different numbers online?
Pages about Mounjaro storage quote either 21 days or 30 days, and both are correct for a different pen. The FDA prescribing information for Mounjaro states that each single-dose pen or vial can be stored unrefrigerated at temperatures not exceeding 30°C for up to 21 days. Lilly UK states that the multi-dose KwikPen must stay between 2°C and 8°C before first use, and can then be kept at up to 30°C for 30 days after first use before it is discarded. The two figures apply to different pens in different markets and are not interchangeable; the leaflet supplied with the pen dispensed to you in the UAE is the figure that applies.
The same pattern applies to semaglutide. Novo Nordisk states that a Wegovy pen can be kept between 8°C and 30°C for up to 28 days before the cap is removed. The FDA prescribing information for Ozempic allows a pen in use to be kept for 56 days at 15°C to 30°C or in the fridge. Which presentation you have depends on the market and the product, so the leaflet in your box is the figure that applies to you.
Why is the 30°C ceiling the harder limit in the UAE?
Every allowance above assumes the pen never goes above 30°C. For much of the year, outdoor temperatures in the UAE exceed 40°C, and a parked car, a balcony or a bag left in the sun exceeds the ceiling within minutes. A pen can be well inside its day count and still have been exposed to a temperature the product information does not cover.
Cars
Never leave a pen in a car, even briefly and even in the glove box. Carry it in an insulated bag with a cool pack that is not in direct contact with the pen, so that the pen stays cool without any risk of freezing against the pack.
Deliveries
If your medication is delivered, put the pen in the fridge as soon as it arrives. The US Food and Drug Administration advises patients not to use an injectable GLP-1 product that arrives warm, so contact the clinic if a delivery arrives warm.
Travel days
On a travel day, carry pens in your hand luggage in an insulated bag with a cool pack, never in checked baggage, where temperatures are not controlled. On arrival, return unopened pens to a fridge and count the time out of the fridge towards the allowance in your leaflet.
Can you put a pen back in the fridge?
It depends on the product. Lilly UK states that a Mounjaro KwikPen in use can go back into the fridge during its 30-day period without affecting its quality. The FDA prescribing information for Zepbound, the weight management version of tirzepatide, states that a single-dose pen kept at room temperature should not be returned to the fridge. The Ozempic label allows a pen in use to be kept either at room temperature or in the fridge.
Because the answer differs by product, follow the leaflet supplied with your pen, and contact the clinic if it does not answer your situation.
How do you tell whether a pen has been affected by heat?
You often cannot tell by looking, which is the reason the temperature rules exist. Check the solution before each injection: it should be clear and colourless to slightly yellow, with no particles or cloudiness, and the pen must never have been frozen. Do not use a pen that fails any of these checks.
A pen that looks normal after heat exposure is not necessarily safe, because the active ingredient can degrade without a visible change, and a pen that has been warm is not necessarily ruined either. Contact the clinic with the details, and do not inject until you have advice. Heat exposure is one of the less obvious reasons for a slower response, covered in our article on why you may not be losing weight on Mounjaro.
How should you store pens at home?
Keep unopened pens in the main body of the fridge, in the original carton, away from the back wall and the freezer compartment, where temperatures can fall below 2°C, and not in the door, where the temperature changes each time it opens. A pen that has frozen must not be used even once it has thawed.
Keep a pen that is in use with its cap on and away from heat and direct sunlight, and note the date it first left the fridge so you can count the days against your leaflet. Our article on how to inject Mounjaro, Wegovy or Ozempic covers technique and needle disposal.
Frequently asked questions
Does Mounjaro need to be refrigerated?
Yes, before use. Keep unopened pens between 2°C and 8°C in the carton; the product information then allows a limited period at not more than 30°C.
How long can my pen stay out of the fridge?
It depends on the medication and the pen type. The official figures are 21 days for a Mounjaro single-dose pen, 30 days for a KwikPen after first use, 28 days for an unopened Wegovy pen and 56 days for an Ozempic pen in use, all at no more than 30°C. Follow the leaflet supplied with your pen.
Can I put my pen back in the fridge?
For some pens, yes, and for others the product information says no, so follow your leaflet. A Mounjaro KwikPen in use can return to the fridge during its 30 days, while the Zepbound label states that a single-dose pen kept at room temperature should not go back in the fridge.
What happens if my pen gets warm?
Do not use it until you have advice. A pen that has gone above 30°C is outside the conditions the product information covers, and heat can degrade the medication without a visible change. Contact the clinic with the details.
How do I tell if a pen has gone bad?
Check the solution before every injection: clear, colourless to slightly yellow, free of particles or cloudiness, and never frozen. A pen that fails these checks, or has been exposed to heat, needs advice before use.
How do I travel with my pen in summer?
In your hand luggage, in an insulated bag with a cool pack that does not touch the pen, and never in checked baggage or a parked car. On arrival, return unopened pens to a fridge and count the days out of the fridge towards your leaflet’s allowance.
If you are unsure whether a pen is still safe to use, contact the clinic before injecting. Endocare’s doctors are always available to support patients with advice.
You can ask an Endocare doctor at our clinics in Dubai and Abu Dhabi.
