Your Wegovy arrived warm — here's what that actually means

Does a warm Wegovy pen mean it's definitely ruined?

Not automatically, no. The Wegovy Patient Information Leaflet specifies a window during which pens can be kept at room temperature (up to 30°C) rather than refrigerated. That window is finite, and the exact figure is stated in the leaflet itself, always read it. The reason a time-limited window exists is that the manufacturer has tested stability at controlled temperatures and established the point at which degradation becomes a real concern.

The complication with delivery is that you rarely know precisely when the pen left cold storage, how long it sat in a courier depot, or what the temperature inside a van reached on a warm afternoon. A pen that arrived slightly cool to the touch may have been fine throughout. One that arrived genuinely warm after a slow delivery during a heatwave is a different matter, and if you've already experienced that situation, our guide on what to do when your Wegovy has got warm walks through the steps to take. Without that data, you're guessing, and guessing with a prescription medicine isn't ideal.

Our clinical team at nume hears this question regularly, and the honest answer is always the same: check the leaflet first, then call your pharmacy. If the pen has been in conditions that exceed the manufacturer's stated limit, do not inject it. The Wegovy treatment overview has more on how the medicine works and what to expect throughout treatment.

What actually happens to semaglutide when it gets too warm?

Semaglutide is a GLP-1 receptor agonist, a large protein molecule that mimics a gut hormone involved in appetite regulation and blood-sugar control. Proteins are sensitive to heat in a way that small chemical molecules often aren't. Sustained warmth can cause the protein structure to unfold or aggregate, a process called denaturation. Once that happens, the molecule may no longer bind to its receptor the way it should.

The practical consequence is reduced effectiveness, not necessarily an obvious change in appearance. A degraded pen might look identical to a good one, same colour, same consistency, no particles you'd notice. That's precisely why visual inspection alone isn't a reliable safety check, and why the stability data from the manufacturer sets the limit, not your eyes.

For more on the chemistry behind semaglutide and where it comes from, the page on what semaglutide is derived from explains the background. The NHS medicines page for semaglutide covers the storage requirements from a patient perspective and is worth bookmarking alongside your leaflet: NHS: semaglutide.

What should you do right now if your pen arrived warm?

Step one: don't inject until you've made a decision you're confident in. Step two: read the storage section of your Patient Information Leaflet, the time-at-room-temperature window is stated there. Step three: if the pen has been warm for longer than that window, or you genuinely can't tell, contact your pharmacy the same day.

A legitimate online pharmacy will have a clinical team available to advise you. At nume, our prescribers are reachable seven days a week through aftercare support, precisely for situations like this. If your pen needs replacing, the conversation about how and whether that happens begins with that call, not with a guess.

Payday orders, Monday deliveries after a bank-holiday weekend, a pen sitting in a depot over a long weekend: these are the scenarios where cold-chain gaps most commonly occur. Being aware of those timing risks before you order is genuinely useful. If you want context on how different providers handle dispatch and delivery, the Wegovy cost and provider comparison page covers what to look for beyond the headline price.

For a deeper read on what happens in specific warm-exposure situations (overnight on a kitchen counter, for instance) the guide on leaving Wegovy out overnight goes into detail. There's also specific guidance if you're weighing up whether to let Wegovy warm up before injecting, which is a separate and common question.

How does cold-chain handling differ between providers?

Not all pharmacies dispatch Wegovy the same way, and the differences matter. Temperature-controlled packaging, rapid next-working-day delivery, and order cut-off times all affect how long a pen spends outside controlled storage. A pen posted second class in a padded envelope during July faces a very different journey than one dispatched same day in insulated packaging via a tracked courier.

The MHRA has a reporting pathway via Yellow Card for suspected quality issues with medicines, including concerns about storage or condition on arrival, that option exists and is worth knowing about. At nume, pens are dispensed from our GPhC-registered pharmacy and sent out by DPD on a next-working-day tracked service, in plain insulated packaging, once a clinician has reviewed and approved the prescription. That doesn't make delivery infallible (couriers are couriers) but it reduces the variables considerably compared to slower, cheaper dispatch options.

If you'd like to explore whether Wegovy is suitable for you, or if you're transferring from another provider and want a clinical re-review, check your eligibility with our prescribers, consultations are free and reviewed the same day.