How Long Wegovy Pens Last in the Fridge — and the Myths Worth Correcting

The myth: 'my pen only lasts 28 days once I get it'

This is a question our prescribers hear most weeks, and the confusion is understandable. The 28-day figure that circulates online usually refers to the out-of-fridge window, how long a pen may be kept at room temperature after it has been removed from the fridge, not how long a refrigerated pen remains usable overall. These are two very different things, and mixing them up leads people to throw away pens that are perfectly fine, or to feel anxious about a treatment they are managing correctly.

An unopened Wegovy pen that stays at 2–8°C is stable until the expiry date on the carton. Most dispensed pens carry an expiry several months away, so if you have a supply of pens in the fridge, the relevant question is not 'how long since it arrived?' but 'what does the label say?'. Check the date on each pen before use; that is the standard the manufacturer and the MHRA work to.

The out-of-fridge window is real and matters, but it applies once a pen has been taken out and kept at ambient temperature. For that figure, the Patient Information Leaflet is the only source you should rely on, because the approved window is specific to the product formulation and can be updated. The separate question of out-of-fridge duration is worth reading if you travel frequently or struggle to keep to a strict cold chain.

Never rely on a pen that has been frozen, even briefly. Freezing irreversibly degrades the semaglutide solution, and a thawed pen will look identical to an intact one. If you are unsure whether a pen dropped below 0°C, contact the pharmacy rather than guessing.

What 'stored correctly' actually looks like in a normal kitchen fridge

Refrigerators are not all equal. The fridge door is the warmest zone and experiences the biggest temperature swings every time it is opened. The shelf nearest the freezer compartment can dip below 2°C unexpectedly if the thermostat is set low. Neither location is ideal for Wegovy pens.

Keep pens flat in the main body of the fridge, on a middle shelf, away from the back wall (where icing can occur on older models). A small, lidded container works well, it keeps the pen from rolling and shields it from direct contact with cold air vents. Keep the pen in its original carton until you need it; the cardboard provides a modest buffer against light and minor temperature drift.

If you share a fridge, the container also acts as a discrete, labelled holder, which matters for a medicine that is prescription-only and not intended for anyone other than the person named on the label. For people who keep multiple pens on hand, organising them with the nearest expiry at the front is a simple habit that prevents waste. You can read more about how long Wegovy pens last overall if you are planning a longer supply.

Temperature excursions (power cuts, fridge failures, moving house) are the most common reasons a pen becomes unusable before its expiry date. A fridge thermometer costs very little and removes guesswork entirely. If the temperature rose above 30°C or dropped below 0°C for any period, treat the pen as compromised and speak to the pharmacy.

Semaglutide in the fridge: does it matter which pen format you have?

Wegovy is available in the standard pre-filled pen format and, since April 2026, as the approved higher-dose 7.2mg single-dose pen. Both are subcutaneous injections and both carry the same refrigeration requirement: 2–8°C until use, never frozen. The MHRA's approval announcement for the 7.2mg pen confirms it shares the same storage framework as the existing Wegovy range.

If you are prescribed a different starting dose pen as part of your titration schedule, the storage rules do not change by dose strength. Each pen in the schedule follows the same cold-chain requirements. For those curious about how long semaglutide will last in the fridge, it is worth knowing that Wegovy's storage compares closely to tirzepatide (Mounjaro), as both injectable GLP-1 medicines require refrigeration, though the specific out-of-fridge windows differ between them, another reason the Patient Information Leaflet for your specific medicine is the document to keep.

People who have moved from the weekly injection to the Wegovy treatment range more broadly (including anyone exploring the oral tablet format) should note that the tablet does not require refrigeration at all, which changes the storage calculation entirely. But for the pen formats, cold storage remains the rule from dispensing to use.

If cost is part of how you are thinking through your treatment plan, the Wegovy price guide sets out what private treatment includes and what legitimate pricing looks like in the UK market.

What to do if you are unsure a pen has been stored correctly

Do not inject from a pen you are uncertain about. The medicine inside has no visible marker for degradation, a pen exposed to freezing or prolonged heat looks exactly like an intact one. The only safe question to ask is whether the cold chain stayed intact, not whether the pen 'looks fine'.

If you received a pen by post and are concerned about transit conditions, contact the dispensing pharmacy directly. Reputable services dispatch temperature-sensitive medicines with appropriate packaging, and a GPhC-registered pharmacy can advise on whether a replacement is warranted. At nume, every pen is dispatched from our own GPhC-registered pharmacy with next-working-day tracked delivery, so the transit window is as short as possible, but if you ever have doubts, our aftercare team is available seven days a week. You can reach us via the contact page.

The MHRA's Yellow Card scheme is also the right place to report any suspected product quality issues, including concerns about storage integrity in transit. Reporting helps the regulator monitor supply-chain standards across all dispensers.

If you are considering starting Wegovy or have questions about whether it suits your circumstances, our guide on how long Wegovy lasts in the fridge is a useful read before you begin, and starting a free consultation with one of our GPhC-registered prescribers is the right first step. Every review is personal, clinical and thorough, the same day you apply.