How to use Wegovy pens: what to do before, during and after each injection

Choosing where on your body to inject

The three approved sites are the abdomen, the outer thigh and the upper arm. All three deliver the medicine reliably, so the choice mostly comes down to what is easiest for you to reach and pinch comfortably. The abdomen tends to be the most practical for self-injection because you can see what you are doing. The outer thigh works well too. The upper arm is possible but usually needs a second person to help if you cannot steady your arm.

Rotation matters more than people expect. Injecting into the same small patch week after week can cause the skin to harden or develop small lumps under the surface (a condition called lipohypertrophy) and from a hardened site the medicine absorbs inconsistently. A simple habit is to move clockwise around the abdomen: left side one week, lower right the next, and so on. You can read more about the licensed uses and clinical background of Wegovy if you want the broader picture before starting.

Stay away from skin that is bruised, reddened, scarred or currently irritated. If you notice persistent redness, swelling or a lump at a previous site, mention it at your next clinical check-in rather than waiting to see if it resolves on its own.

Preparing the pen: the steps before you press the button

Wegovy pens are kept in the fridge (between 2 and 8°C), and you can find out more about the different Wegovy pens available and how they are supplied if you want to know what to expect before your first delivery. Before an injection, take the pen out and let it reach room temperature for around 15 to 30 minutes. Cold medicine going under the skin can sting more than it needs to. Check the expiry date on the label and look through the viewing window: the liquid should be clear and colourless or faintly yellow, with no particles floating in it. If it looks cloudy or contains flecks, do not use that pen and contact your prescriber.

Wash your hands thoroughly. Then clean the chosen injection site with an alcohol swab and let it air dry fully, injecting into damp skin stings and can affect how cleanly the needle enters. Remove the pen cap by pulling it straight off rather than twisting, and keep it to hand. You will see a green liquid inside the viewing window. The needle is already sealed inside the cap you just removed; you do not need to attach anything.

The step-by-step walkthrough for the Wegovy pen mechanism goes into the pen's built-in safety system in more detail, which is particularly useful if you want to understand why the plunger does not move like a conventional syringe.

The injection itself and what to expect during it

Pinch a fold of skin gently at the cleaned site and hold it throughout the injection. Place the pen flat against your skin, do not angle it. Press the pen firmly down until you feel it click, then press and hold the injection button. Keep pressing down on the pen with your thumb until a second click tells you the full dose has been delivered, then hold for a further ten seconds before lifting the pen away. That pause matters: lifting too soon can pull some of the dose back out with the needle.

A small amount of blood or clear fluid at the site afterwards is not a problem; apply gentle pressure with a clean piece of cotton wool. Do not rub the site. Once you have finished, replace the cap carefully and place the pen in a 1-litre sharps container rather than the normal bin, household waste collection cannot safely handle used needles. Council websites list local disposal points, and some pharmacies will accept sealed sharps bins.

If you are new to Wegovy or thinking about starting, our guide to getting started with Wegovy covers dose titration and what the first weeks on treatment typically feel like.

After the injection: storage, routine and side effects to watch

Return any unused pens to the fridge promptly. Wegovy can sit at room temperature below 30°C for a limited period if needed for travel, but the exact window is set out in the Patient Information Leaflet, always go by that rather than any general figure you find online. The SmPC on the Electronic Medicines Compendium has the full prescribing information, including storage conditions.

The most common side effects after an injection are gastrointestinal: nausea, burping, loose stools, or a feeling of fullness that arrives faster than usual at mealtimes. These tend to be most noticeable in the first days after a new or increased dose and settle as your body adjusts. If you are ever unsure whether you are injecting correctly, our detailed guide on how to use your Wegovy pen can help you check your technique. Staying well hydrated and eating smaller portions helps most people through the early weeks.

Seek medical advice promptly if you develop severe stomach pain that spreads to your back, with or without vomiting. This can, in rare cases, indicate pancreatitis. The MHRA highlighted this risk in a Drug Safety Update for GLP-1 medicines in January 2026. You can also report unexpected reactions directly through the Yellow Card scheme at yellowcard.mhra.gov.uk.

Wegovy is a prescription-only medicine. A GPhC-registered prescriber assesses suitability before any treatment begins, and your dose is reviewed at every stage. If you have questions about the injection process or your current dose, the clinical team is available seven days a week. Those who haven't yet started treatment can get a sense of what a supported weight-loss programme looks like before committing to anything.