The right temperature to store Wegovy (and what to do if something goes wrong)

The moment your pen arrives and what to do first

Picture this: a plain, unbranded box appears at your door, DPD tracking having pinged you that morning. Inside, your Wegovy pen is packed for transit, but the clock on correct storage has been running since it left the pharmacy. The first thing to do when it arrives is move it into the fridge. Not later. Straight away.

The fridge temperature that matters is 2°C to 8°C. That is the range specified in the Wegovy Summary of Product Characteristics, and it applies to every pen in the box, opened or not. A fridge running warmer than 8°C provides insufficient protection; one that strays below 2°C (especially near the back panel or the freezer compartment) risks freezing the solution, which damages it irreversibly. If you want to understand the full detail of Wegovy storage temperature requirements and why each boundary matters, that page explains the science behind the range. A fridge thermometer is a cheap and genuinely useful addition if you are not certain where your appliance sits.

Keep pens in their original carton. The packaging blocks light as well as acting as a reminder of expiry dates and the batch number you would need if you ever had to report a concern via the MHRA's Yellow Card scheme. Do not stand pens loose in the fridge door, where temperature swings are greatest every time the door opens.

For a broader look at how Wegovy works and what the treatment involves, that page covers the full picture.

Room temperature: the in-use window and why there is a limit

Once you begin using a pen, the guidance allows a period at room temperature, below 30°C, away from direct heat and light. The precise number of days is printed in the Patient Information Leaflet inside every Wegovy pack; always read that leaflet for the figure that applies to your pen, because it is the document the MHRA has approved as accurate for the product you hold.

The reason there is a limit at all comes down to protein stability. Semaglutide, the active medicine in Wegovy, is a peptide, and if you want a full explanation of what temperature semaglutide needs to be stored at and why that matters for the molecule, that page covers the science in detail. Sustained exposure to warmth gradually degrades the molecule, reducing its potency before the expiry date printed on the label would suggest. You would not necessarily be able to see or smell any difference, which is exactly why the printed timeframe matters rather than a visual check.

If you have been keeping a pen out of the fridge longer than the leaflet allows, do not inject it. Contact your prescriber or a pharmacist to discuss whether it can still be used safely. For questions about how long Wegovy can sit at room temperature in specific circumstances, that page goes into more detail.

The NHS semaglutide medicines page also covers storage in patient-facing language and is worth bookmarking alongside your leaflet.

What happens if a pen gets too cold or too warm

Freezing is the more common accident. It tends to happen when a pen is stored near the back of the fridge, where the temperature can dip below 2°C without the dial moving, or when it is accidentally placed in the freezer. A frozen pen should not be used even after it has thawed; the freezing process can cause the solution to change in ways that are not visible to the eye. If you suspect a pen has been frozen, set it aside and speak to your pharmacist or prescriber before injecting.

Excessive heat (a sun-baked car dashboard, a bag left on a warm radiator, direct sunlight through a window for an extended period) carries the same message: the pen may no longer be reliable. When in doubt, contact a clinician rather than guessing.

Travelling with Wegovy adds a layer of planning. A small insulated cool bag with an ice pack can bridge the gap between your fridge at home and wherever you are going, provided the pen does not touch the ice directly (contact with ice can locally freeze the solution). If you are unsure what temperature Wegovy should be stored at across different real-world situations, that page addresses travel, power cuts and other practical scenarios in more depth.

If you are thinking about whether Wegovy is the right treatment for you, our free consultation connects you with a GPhC-registered Independent Prescriber who can review your circumstances the same day.

A note on injection technique and temperature comfort

A separate but related question our prescribers hear fairly often: does the pen need to reach room temperature before you inject? Cold medicine can sting more at the injection site, and some people find the experience more comfortable after letting the pen sit out for a few minutes. The answer to that practical question, and whether your specific pen's in-use window permits it, is covered in detail on the page about whether Wegovy should be at room temperature before injection.

On injection sites themselves: rotating between the abdomen, thigh and upper arm reduces the chance of localised skin reactions. Cleaning the site beforehand is straightforward, alcohol swabs are a small practical addition worth keeping with your pen. After each injection, needles should go directly into a sharps bin; if you need one, a 1-litre sharps container is available from our pharmacy.

Wegovy is a prescription-only medicine. It is assessed by a clinician, not dispensed over the counter. If you have questions about storage that feel urgent (a pen left somewhere warm, a fridge that stopped working overnight) call NHS 111 or speak to your pharmacist the same day rather than waiting. For everything else, the Patient Information Leaflet is your first and most reliable resource, and our aftercare team is available seven days a week if you need support.