How long will semaglutide last in the fridge — and what affects it?

What does 'store in the fridge' actually mean for a semaglutide pen?

The phrase covers a specific temperature band: 2°C to 8°C, which is the normal range of a domestic refrigerator set correctly. The freezer drawer (even if it only reaches the top shelf of your fridge) falls outside this range. Semaglutide is a protein-based medicine, and freezing can permanently alter its structure. A pen that has been frozen and then thawed may appear perfectly normal but could deliver less active medicine than expected. Worth knowing before you assume the bottom of the fridge door is fine.

Placement matters too. The coldest part of most fridges is at the back and near the base; the door shelves are the warmest. Keeping your pen towards the middle of a shelf, away from the back wall where temperatures can dip toward freezing, is a practical step. The Wegovy overview on our site has more on the basics of starting treatment.

The NHS medicines page for semaglutide confirms that pens should be kept refrigerated and kept away from children, straightforward guidance, but easy to overlook when the pen is sitting in the fridge door next to everything else.

How long does an in-use Wegovy pen last before it needs to be used or discarded?

This is the question most people actually mean when they search for how long Wegovy will last in the fridge, covering both the unopened expiry date and the shorter in-use window that starts from your first dose. An unopened pen is governed by its printed expiry date. Once you have administered your first dose from a pen, a separate in-use clock starts, and that window is shorter.

The exact figure is stated in the Patient Information Leaflet enclosed with your pen. Wegovy pens contain four weekly doses at a given strength, so in practice you will use each pen over roughly four weeks; the in-use period is designed around that pattern. Our guide to how long Wegovy pens last in the fridge walks through the in-use rules in detail, and it is worth reading alongside your own leaflet.

During the in-use window, the pen can also spend some time at room temperature, useful for travel or days when the pen needs to be out of the fridge for a while. How long that is permitted, and under what conditions, is again specified in the leaflet rather than in general guidance, because different strengths and pen formats carry slightly different data. The room-temperature rules for Wegovy are covered separately if that is what you need.

What happens if the pen has been stored incorrectly, can you still use it?

A pen that has been frozen, left in a hot car, or exposed to direct sunlight should not be used, even if it looks undamaged. Visual inspection alone cannot confirm the medicine is intact, the protein structure of semaglutide can degrade without any visible change to the liquid. If the solution looks cloudy, discoloured, or contains particles, that pen should also be discarded.

If you suspect a temperature excursion has occurred (say, the fridge was switched off overnight, or the pen was left out and you are not sure for how long) the safest step is to contact your prescriber or pharmacist before your next scheduled injection. Injecting a degraded pen is not harmful in the way a contaminated medicine would be, but it may mean your dose is effectively lower than intended, which matters for how well your treatment is working.

For anyone managing out-of-fridge time for semaglutide on a regular basis, noting the date and time the pen left the fridge is a simple habit that removes the guesswork. It is also the kind of detail our prescribers are glad to talk through if you are unsure about your specific situation, you can reach the team via our contact page.

Does pen format change the storage rules, and what about the newer 7.2mg pen?

Different Wegovy pen formats carry their own SmPC data, so the storage rules should be confirmed from the leaflet specific to your pen. The MHRA approved a dedicated single-dose 7.2mg semaglutide pen on 14 April 2026, a higher-dose format with a built-in covered needle that locks after use. As with earlier Wegovy pens, refrigerated storage at 2–8°C applies; for in-use rules specific to that pen format, the Patient Information Leaflet is the definitive source.

The Wegovy tablet (oral semaglutide), approved in the UK in June 2026, is a separate medicine and does not require refrigeration at all. If you are on or considering the oral semaglutide option, room-temperature storage is part of its design. That is a meaningful practical difference for people who travel frequently or have limited fridge space.

If you are starting out and want to understand the full picture of what using a semaglutide pen involves day to day, the injection kit guide covers equipment, preparation and disposal in one place. Proper sharps disposal is straightforward with a standard 1-litre sharps container, most local councils collect these free of charge.

Semaglutide is a prescription-only medicine. A prescriber assesses your clinical picture before any treatment begins. If you are thinking about starting or have questions about managing your current treatment, you are welcome to check your eligibility with our team, consultations are free, and a GPhC-registered prescriber reviews every application the same day.