How to store your Wegovy pen after first use

Can you leave a Wegovy pen out of the fridge once it has been started?

Yes, and this surprises a lot of people who assume a medicine pen always needs to go straight back into the fridge. Once the first dose has been injected, a Wegovy pen may be stored out of the fridge at room temperature, provided the temperature stays consistently below 30°C. The 28-day window runs from the moment the pen was first used, not from the date you started the box.

Think of that window as a deadline, not a safety buffer to push. If day 28 falls mid-week and the pen still has doses left, it still gets discarded. Writing the date of first use on the pen label with a marker is one of the simplest things you can do to keep track.

In practice, many people find it easiest to keep the in-use pen on a shelf away from windows and radiators, somewhere visible enough that the daily routine is obvious. The fridge door next to the milk works just as well, provided your fridge does not drop below 2°C at that spot. What you want to avoid is the pen migrating to a handbag, a car glove compartment or a sunny windowsill, where temperatures can climb well above 30°C without you noticing. Our general Wegovy storage guide covers travel and holiday scenarios in more detail.

What happens if the pen gets too cold or too warm after first use?

Both extremes cause problems, though freezing is the more serious one. Semaglutide solution that has been frozen (even once) should not be injected. Ice crystal formation can alter the protein structure of the medicine, and there is no reliable way to tell whether the dose is still intact after thawing. If a pen has accidentally spent time in a freezer or has been packed against a freezer block in a cool bag, the safest course is to contact your prescriber before using it.

Heat damage is subtler. A pen left in a car on a warm day can reach temperatures well above 30°C inside the vehicle, studies on car interior temperatures regularly record 50°C or above in UK summer conditions. The pen will look normal, but the potency of the medicine cannot be guaranteed. This is not a reason to panic if it happened once briefly; it is a reason to be honest with yourself about whether it is within the expected storage range, and to speak to your pharmacist if you are unsure.

Direct sunlight causes similar degradation. The outer cap is there for a reason, keep it on between injections, and store the pen away from windows. The NHS semaglutide medicines page confirms that pens should be kept away from heat and direct light.

Does the storage rule change at different Wegovy doses?

No. The 28-day room-temperature rule applies across the titration schedule, from the 0.25mg starter dose right through to the 2.4mg maintenance dose and the newer 7.2mg strength. Each pen contains four weekly doses. Whether you are on your first injection or your tenth month of treatment, the clock starts on the day you first use a pen and stops at 28 days.

One thing worth understanding early in treatment: the first pen at 0.25mg is a tolerability dose. Its job is to let your body adjust to semaglutide, and most people will use only one dose from it per week for four weeks before moving to 0.5mg. Each new strength comes in its own pen, and the 28-day counter resets with each one.

If you are just starting out and still getting to grips with how everything fits together, our guide to Wegovy pen first use walks through preparation and technique before the storage question even arises. Questions about your specific dose schedule are best directed to your prescriber, who can advise based on your clinical record.

What should you do with an expired or damaged pen?

An expired pen (one that has been out of the fridge for more than 28 days, or that has passed its printed expiry date) must not be used. The same applies to a pen you suspect has been frozen, overheated or dropped in a way that may have damaged the mechanism. Using a compromised pen risks both an ineffective dose and potential harm from a faulty injection.

Disposal matters too. Wegovy pens are medical sharps. Used needles should never go into a household bin. A small sharps container keeps used needles safe until your local pharmacy or household waste collection can take them, most community pharmacies accept sealed sharps bins at no charge.

If you have questions about a specific pen (whether it has been stored correctly, whether a misfire means it needs replacing, or how to handle a dose you are not sure about) our prescribers are on hand seven days a week through aftercare. For a broader look at how Wegovy works as a treatment, or to understand what the private prescription process involves, those pages are worth a read. If you are ready to talk through your treatment with a clinician, you can speak to our prescribers through a free consultation. You may also find it helpful to read through our guide to using Wegovy for the first time, which covers everything from getting started to what to expect from your initial doses, alongside how to use the Wegovy pen for your first injection, which covers the practical steps in detail.