Semaglutide left out of the fridge: what the guidance actually says

What the prescribing guidance says about semaglutide outside the fridge

The Wegovy SmPC (the detailed prescribing document published on the Electronic Medicines Compendium) is the primary authority on how semaglutide should be stored. It confirms that Wegovy pens must be kept refrigerated at between 2°C and 8°C when not in use. After that, there is a permitted room-temperature period before the pen must be discarded. The exact number of days is printed in your Patient Information Leaflet, which you will find folded inside the carton.

The reason we do not state that figure here is deliberate. Storage windows can be updated between manufacturing batches or pack versions, and the safest single source is always your own leaflet, not a webpage. If you no longer have the leaflet, your prescriber or pharmacist can confirm the current limit.

Room temperature for storage purposes generally means below 30°C. A warm car dashboard, a sunny windowsill or a bathroom shelf near a shower can push well past that, even briefly. The cumulative time out of the fridge is what counts, not just the most recent occasion.

If you are weighing up whether a Wegovy pen is still usable after being left out, time is the first thing to check, but temperature and light exposure matter just as much. A pen left at 25°C for three hours is very different from one left at 35°C on a kitchen counter for two days.

How semaglutide can be damaged by poor storage conditions

Semaglutide is a peptide medicine: a protein-based compound that is sensitive to temperature extremes in both directions. Freezing is just as damaging as overheating. A pen that has been frozen (even once) should not be used, regardless of whether it has thawed back to room temperature. Proteins in solution can aggregate (clump) when frozen and thawed, which changes the medicine's behaviour in ways that are not visible to the eye.

Heat and prolonged light exposure carry similar risks. A degraded pen may look identical to a working one. The solution should be clear and colourless; if it appears cloudy, discoloured or contains visible particles, do not use it. The NHS semaglutide medicines page advises checking the appearance of the solution before each injection and not using it if anything looks different from usual.

Understanding what happens if Wegovy is not refrigerated properly can help explain why the injection device itself can also be affected by temperature stress, as the mechanism that drives the pen and the needle-seating can be altered by sudden heat or cold. This is one reason storage rules cover the pen as a unit, not just the liquid inside it.

For anyone travelling with Wegovy (bank holidays, a weekend away, a fortnight abroad) a small insulated cool pouch designed for medical pens is worth considering well before the trip. Planning around the 12pm same-day dispatch cut-off can also help if you are ordering a replacement before a bank holiday.

What to do if your semaglutide pen has not been refrigerated long enough, or too long

If your pen has been out of the fridge for less than the time allowed in your leaflet and has not been frozen or exposed to excessive heat or direct sunlight, it is generally expected to be within acceptable limits. Continue to keep it below 30°C and use it within the remaining window.

If the time limit has been exceeded, or you are not certain how long the pen has been unrefrigerated, our guide to whether you can still use Wegovy if it has not been refrigerated sets out the factors to consider, but as a general rule you should contact your prescriber or pharmacist before proceeding. Using a degraded pen is not a neutral act: you may receive less medicine than intended, which disrupts your titration schedule, and in rare cases a compromised solution could cause an unexpected reaction at the injection site.

Replacing a damaged pen is straightforward through a regulated online pharmacy. For context on what to expect from private treatment costs when a replacement is needed unexpectedly, the Wegovy cost page covers how private pricing is structured in the UK. Once clinical review confirms a new prescription is appropriate, guidance on administering semaglutide correctly is a useful refresher before starting a fresh pen.

If you received a pen through a seller you cannot verify on the GPhC pharmacy register, and you have concerns about whether it was stored correctly in transit, report it via the MHRA Yellow Card scheme, this covers suspect medicines as well as side-effect reports, and the MHRA takes reports of supply-chain concerns seriously.

Keeping storage manageable in practice

Most people settle into a simple routine. The pen lives in the fridge door, below the shelf where anything might freeze. When you are due to inject, you take it out around 30 minutes beforehand so it reaches a comfortable temperature; injecting cold liquid can sting more. After injecting, Wegovy pens are single-use per week: one injection, then the pen is capped and returned to the fridge until the same day next week.

On trips, a validated cool wallet keeps temperatures within range without needing a freezer pack. A reusable sharps container for safe disposal when you are away from home is worth having, a one-litre sharps bin is compact enough for most travel bags.

If you are new to semaglutide or currently exploring whether weight-loss treatment is right for you, storage might feel like a small detail now. It becomes second nature quickly. The bigger picture (whether semaglutide suits your health profile, what starting dose makes sense, and how your progress should be monitored) is exactly what a clinical consultation is for.

Our prescribers at nume review every consultation personally. If storage questions come up at any point during your treatment, they are there to answer them. Speak to our prescribers through a free consultation to find out whether Wegovy is clinically appropriate for you.