How to Set Up a Wegovy Pen Before Your First Injection

Should you inject straight from the fridge, or wait?

This is the most common hesitation at setup, and the answer shapes everything that follows. Wegovy pens are stored refrigerated at 2–8°C, and injecting cold semaglutide can sting more than it needs to. Letting the pen sit at room temperature for around 30 minutes before you start is a straightforward way to make the injection more comfortable. There is a limited window during which the pen can be kept out of the fridge, the exact duration is stated in the Patient Information Leaflet that comes with your pen; always check it rather than relying on memory or online estimates, because the window differs depending on whether the pen has been opened.

While you are waiting, do two things: wash your hands thoroughly, and run a quick visual check. Hold the pen up to the light and look at the solution through the inspection window. Clear or very slightly hazy is fine. If you spot floating particles, cloudiness or a colour change, set that pen aside and contact your prescriber or pharmacy. It takes under a minute, and it matters. The NHS patient information for semaglutide covers this check alongside other pre-use steps worth reading before your first dose.

Attaching the needle: why the sequence matters

The needle is not attached when the pen leaves the pharmacy. You fit a new one before each injection, even if the pen still has doses remaining. This keeps the needle sterile and prevents the solution from leaking or air from entering between doses.

Pull the paper tab off the outer needle cap, then press the capped needle straight onto the pen tip. Turn it clockwise until it is snug, firm, not forced. Pull off the outer cap and keep it to one side; you will need it to remove the needle safely afterwards. Then remove the inner cap and discard it. Do not put the inner cap back on. If you want a full walkthrough of the device from start to finish, the guide on how to use the Wegovy pen covers each step of the process, including how the cap and seal sequence leads into needle attachment. If you are looking for details on how each part of the device fits together, the guide to opening a Wegovy pen walks through the cap and seal sequence before needle attachment.

Use a fresh needle each time. Reusing needles blunts the tip, risks blockages, and increases the chance of injection-site discomfort. If you need to restock, compatible pen needles are available separately.

Priming the pen and confirming flow

Before the very first injection from a new pen, you prime it to remove any air from the needle and confirm the mechanism is working. Turn the dose dial to the priming symbol (a small arrow or dot depending on the pen version, check your leaflet). Point the needle upward and tap the pen gently. Press the injection button and hold it until a drop of liquid appears at the needle tip. That drop is your confirmation.

If no drop appears after a second attempt, do not increase the dose or use a different pen without speaking to your prescriber. Troubleshooting a pen that will not prime is covered in the Wegovy pen reset guide. Once you have confirmed flow, you are ready to select your prescribed dose and inject. The full injection sequence (site selection, angle, button hold time) is covered in the step-by-step Wegovy injection guide.

After the injection: disposal and what to watch for

Once you have injected, keep the button held down for at least six seconds before withdrawing the needle from the skin. This ensures the full dose has been delivered. Then use the outer needle cap to cover the needle (scoop it on rather than reaching for the cap with your fingers) and unscrew the needle from the pen. Loose needles should not go in a household bin. A sharps container is the correct disposal route, and many pharmacies and GP surgeries will collect full ones. Throwing away the pen itself is a separate question, the guide on Wegovy pen disposal explains what applies in the UK.

After your first injection, keep an eye on how you feel over the next 24 hours. Nausea, mild stomach discomfort and fatigue are among the most commonly reported effects when starting or increasing semaglutide, and they tend to settle within a few days for most people. If you experience severe or persistent stomach pain, stop the injection and seek medical advice promptly. The NHS England guidance on weight management injections includes a summary of when to seek urgent help.

If you are still deciding whether Wegovy is right for you or want to understand how it compares to other options, the weight-loss treatment overview sets out what is licensed in the UK and how private access works. Starting a free consultation with a prescriber is the clearest way to get a clinical view on your situation.