Should Wegovy be stored in the fridge — and what happens if it's not?

The myth: Wegovy has to stay in the fridge the whole time you're using it

This is the most common misunderstanding, and it causes real anxiety, people on holiday, people who've left a pen on the kitchen counter overnight, people who've discovered their fridge ran too cold. The truth is more practical. Wegovy pens do need to be kept refrigerated, but only until you start using one. Once a pen is out of the fridge, it can be kept at room temperature (up to 30°C) for up to six weeks before it must be discarded. That six-week window covers most real-life situations: a fortnight's holiday, a business trip, a week at a relative's house.

The rule that is absolute, and worth reading twice, is about freezing. A Wegovy pen that has frozen (even briefly, even if it looks fine after thawing) should not be used. The biological structure of semaglutide is sensitive to ice crystal damage. If your pen has been stored directly against the back wall of a fridge that runs very cold, or in a freezer compartment by mistake, check the PIL before injecting. When in doubt, contact our support team or your prescriber.

The NHS semaglutide medicines page confirms both the fridge requirement and the room-temperature limit, and is worth bookmarking alongside your pen's own leaflet.

What the fridge actually does, and why temperature matters for a biological medicine

Semaglutide is a large biological molecule, a modified version of a naturally occurring gut hormone. That is very different from a small-molecule tablet, which tends to be stable at room temperature for years. Biological medicines are sensitive to conditions that would leave a paracetamol tablet unaffected: sustained heat, freezing, and prolonged exposure to light can each alter the protein structure and reduce how well the medicine works.

Keeping the pen in the fridge door (rather than the back wall) is a practical habit worth adopting, it avoids both the warm fluctuations of the door seal and the deep-cold zone near the back. Think of it like keeping butter: technically the door shelf, reasonably consistent, never next to the ice tray. For travel, a small cool bag with a gel pack works well, provided the pen is not resting directly on the ice pack itself; the goal is cool, not frozen.

If you want to understand more about the medicine itself, the Wegovy overview page covers how semaglutide works and what to expect from treatment. For a detailed look at the specific temperature thresholds and what happens at each, this page on the exact temperatures Wegovy should be kept at goes through the numbers carefully.

Room temperature, travel and the situations people actually encounter

The six-week out-of-fridge window is genuinely useful, but it comes with conditions. First, the temperature ceiling is 30°C. In a British summer that is mostly fine; in a car parked in direct sun in July, the inside temperature can reach 50°C or above. Do not leave pens in a glove box or on a car seat. Second, the clock starts from the moment the pen comes out of the fridge for the last time, not from first use.

A question our prescribers hear regularly: "I took my pen out of the fridge for a weekend trip, used one dose, and then put it back in the fridge when I got home. Has that reset the clock?" It has not. The six-week period is cumulative from first removal, and returning a pen to the fridge does not extend it. Keep a note of the date you first removed each pen, particularly if you are not injecting every week from the same pen.

If you have ever wondered whether Wegovy has to be stored in the fridge throughout treatment, or exactly how fridge storage applies to your pens day to day, those pages set out the full picture in plain terms. For context on how this compares with other weight-loss injection options, the semaglutide and related injection page outlines the broader landscape. And if you are still weighing up whether injections or a different approach suits your situation, the weight loss treatment overview may help you think it through.

One related practical point: when pens go out of condition and need safe disposal, a sharps container is the correct way to dispose of any used or unusable pens at home.

When to call for help and how to get the storage details right from the start

Storage questions are not trivial. Using a pen that has been damaged by temperature changes may mean you receive a reduced dose without realising it, the liquid can look identical whether or not the medicine is intact. If you are ever unsure whether a pen has been stored correctly, the safest position is to contact your prescriber before injecting rather than after.

The full Wegovy storage guide covers the step-by-step detail, including what the PIL says about each scenario. For anything about whether storage has been breached and what to do next, that is a clinical question: reach out via our contact page and a member of the team will help you reach the right person.

If you are not yet on treatment and are thinking about whether Wegovy is the right option for you, a free consultation with a GPhC-registered prescriber is the place to start. Our clinical team, including our lead prescriber, reviews every consultation personally. Check your eligibility and start your free consultation.