How do you store semaglutide — and why it matters more than you'd think

Does semaglutide always need to go in the fridge?

The short answer is yes, until the pen is opened. Wegovy pre-filled pens should be refrigerated at 2–8°C from the moment they leave the pharmacy until you start using them. That means the fridge, not the freezer. Freezing semaglutide is one of the most common storage mistakes, even brief contact with a freezer compartment or a very cold spot near the back of the fridge can crystallise the solution and render it unusable. If a pen has been frozen, do not inject it; the NHS patient guidance on semaglutide makes clear that affected pens should be discarded.

Placement inside the fridge matters too. Store pens towards the middle of the fridge rather than in the door, where temperatures fluctuate each time you open it, and away from the cooling element itself. The original box offers useful protection from light, leave each pen in it until injection day. If you are thinking about where in your home the fridge is the most stable and least tampered with, our guidance on choosing the right storage spot covers that in more detail.

What happens to the pen once you have started using it?

In-use Wegovy pens can be kept at room temperature for a defined period without refrigeration, which matters for people who travel or work long days away from home. The exact number of days allowed is stated in the Patient Information Leaflet for your specific product, and because Novo Nordisk has introduced both a standard 2.4mg pen and the newer 7.2mg single-dose pen (approved by the MHRA in April 2026), the leaflets for each format should be read separately rather than assumed to be identical. If you are unsure which format applies to you, our page on the semaglutide injection brand you have been prescribed can help clarify the differences.

Room temperature here means below 30°C. A car parked in summer sun, a bag left near a radiator, or a windowsill in direct light can push beyond that easily. If there is any doubt about whether a pen has been stored correctly, the right call is to speak to your pharmacist or prescriber before injecting. Wasting one dose is a far smaller problem than injecting a degraded medicine. If you want a clear overview of how long the room-temperature window lasts, our page on semaglutide storage duration walks through the relevant details.

Are there any storage risks specific to how semaglutide is injected?

The injection itself introduces a few extra considerations. Each time you prepare to use the pen, the needle should be attached just before you inject (not left attached between doses) because a needle left in place can allow air into the cartridge and affect the dose. Our compatible needle packs are available if you need a resupply. Similarly, the injection site (abdomen, thigh, or upper arm) should be clean and dry; alcohol swabs help keep each site properly prepared.

Used needles are sharps and must not go in household bins. A 1-litre sharps container makes disposal straightforward and safe, and many GP surgeries and pharmacies accept full containers for clinical waste disposal. None of this is complicated once the routine is established, it just takes a few days to feel natural. The Mounjaro and Wegovy SmPCs on the eMC contain the manufacturer-approved storage tables if you want the primary source rather than a summary.

What should you do if something goes wrong with storage?

If a pen has been left at room temperature longer than the leaflet permits, accidentally frozen, or stored somewhere that got too warm, do not use it without checking first. The medicine may look identical but the active ingredient can degrade without any visible sign. Contact your prescriber or the dispensing pharmacy, at nume, our prescribers are available for aftercare seven days a week, and storage questions are exactly the kind of thing they are there for. You can also find general guidance through our FAQ page.

One point worth knowing: semaglutide for weight management (Wegovy) is a prescription-only medicine requiring a clinical assessment before it can be dispensed. The storage question usually arises once treatment is already underway, but if you are still working out where to get Wegovy through a regulated UK pharmacy, that is a separate step that comes first. And if you are curious about storage that is specific to the Wegovy pen format, that page goes into more product-specific detail. Our Wegovy overview is a good starting point if you want the broader clinical picture before focusing on the practicalities. Speak to our prescribers if you have any questions about your treatment, a free consultation is the first step.