How Long Does a Wegovy Pen Last?

Step 1, Receiving and storing your pen before first use

Your Wegovy pen arrives refrigerated, packed to maintain temperature during transit. The moment it lands with you, it goes straight into the fridge at 2–8°C, away from the freezer compartment and away from any direct cold source at the back of the shelf. Freezing destroys the medicine; a pen that has frozen must not be used.

At this stage the pen counts as unused, and the clock for in-use storage has not started. You have time (though not unlimited time) before the expiry date printed on the label. Check that date as soon as you put the pen away. It takes under a minute and has saved more than one patient an awkward conversation with their pharmacy. Our guide to Wegovy fridge storage covers the temperature detail thoroughly if you want to go deeper.

If you are transferring to a higher strength or starting a new prescription cycle, your pen from a different strength is not interchangeable with your current one. Each strength is its own pen and its own four-week supply. Store them separately and label clearly if you have both in the fridge at once.

Step 2, Your first injection and the four-week count

The day you press the pen for the first time is Day 1 of that pen's four-week life. From that moment, the in-use storage rules apply, and if you want a full breakdown of exactly what that window looks like in practice, our page on how long one pen of Wegovy lasts explains the timeline dose by dose. The Patient Information Leaflet specifies how long the pen may be kept once you have used it, including any limited time it can spend outside the fridge. Always check the leaflet for the exact window rather than relying on a remembered figure, because storage rules can differ between medicine batches and presentations.

Each of the four doses is delivered by pressing the pen against clean skin at the injection site and holding it until the click confirms delivery. Rotating sites (abdomen, thigh, upper arm) reduces local irritation over time. If you are unsure whether a dose went in correctly, our page on what to do if a Wegovy injection has not gone in properly walks through the checks step by step.

Needle changes matter too. A fresh needle every time protects the injection site and keeps the mechanism accurate. Pre-owned needles can carry microscopic barbs that increase soreness. You can find compatible replacement needles if you need a resupply mid-pen.

Step 3, Completing the pen and ordering the next one

After dose four the pen is empty. It should be disposed of safely in a sharps container rather than the household bin; your local pharmacy or GP surgery can advise on collection points. Do not attempt to refill or reuse it.

Ordering timing is worth thinking about before you reach that final dose. Wegovy is a prescription-only medicine, which means each repeat supply requires a fresh clinical review. At nume, every repeat order goes through a prescriber before dispatch, no auto-renewing subscription, no standing order sent without anyone looking. Order by 12pm Monday to Friday and, once clinically approved, your next pen is dispatched the same day and delivered free the next working day by DPD.

If you are planning a holiday or a period away from home, factor in the storage requirement. The pen cannot simply sit in a bag at room temperature for a fortnight. Our overview of Wegovy for weight management includes practical notes on travel and continued treatment for those mid-programme.

When the pen lifespan question gets more complicated

A few situations change the simple four-weeks-per-pen answer. If you miss a dose and it falls within three days of when it was due, you can take it and continue on your usual schedule; if more than three days have passed, skip it and wait for the next scheduled dose. That means a pen may technically stretch across more than four calendar weeks if doses are missed, but the pen still holds only four doses. The NHS semaglutide page has clear guidance on missed doses; your prescriber is the right person to call if you are unsure.

Switching strengths mid-pen is not possible. If your prescriber increases your dose, you move to a new pen at the higher strength; any remaining doses in the old pen are not transferred or topped up. The same applies in the other direction if a dose reduction is clinically needed.

The cost angle is worth a brief mention here. Because one pen covers four weeks, the monthly treatment cost equals one pen's cost. Understanding what is included in a private prescription (clinical review, delivery, aftercare) helps you compare services on the right basis, not just the headline pen price. For a prescription medicine, the cheapest listing tends to answer the wrong question.

Semaglutide is also the active ingredient in Ozempic and, as oral tablets, in Wegovy's newer pill form, but those are separate licences and separate presentations, and our guide on how long a semaglutide pen lasts covers how the in-use rules compare across those different devices. If you have seen references to Ozempic for weight loss, it is worth knowing it is not licensed for that purpose in the UK. The injection pen discussed on this page is the weight-management-licensed Wegovy device specifically.