How to give a semaglutide injection with a syringe: a step-by-step guide

Step 1: Understand what you should have received

Wegovy (the brand name for semaglutide licensed in the UK for weight management) comes as a pre-filled injection pen. Each pen contains four weekly doses (or, in some formats, is a single-use device). You do not load a syringe. You do not break open a vial. You do not measure anything. If a product arrived looking like a vial with a rubber stopper and a separate needle for drawing up liquid, it is not the licensed UK product, and if you want to understand what that process actually involves you can read our page on how to inject semaglutide with a syringe to see exactly why it differs from the genuine pen-based format. The MHRA has urged people to report suspect products via the Yellow Card scheme, and enforcement operations have seized tens of millions of doses of counterfeit and unlicensed weight-loss medicines in the UK since 2023. A genuine pen from a regulated UK pharmacy arrives in plain, unbranded packaging (tracked to your door) with the Novo Nordisk markings clearly printed on the device itself.

If you are unsure whether your product is genuine, do not use it. Contact your prescribing service, your GP, or report it to the MHRA.

Step 2: Prepare for your injection properly

Assuming you have a genuine Wegovy pen, preparation is straightforward. Wash your hands thoroughly with soap and water before handling the device. Take the pen out of the fridge and allow it to reach room temperature for roughly 30 minutes, cold medicine tends to sting more on injection. While it is warming, choose your injection site: the abdomen (at least a couple of centimetres from the navel), the front of the thigh, or the upper arm are all suitable. Rotate the site each week so you are not repeatedly injecting the same patch of skin. Check the pen window: the liquid should be clear and colourless, with no particles floating in it. If it looks cloudy or discoloured, do not use it.

Clean the chosen area with an alcohol swab and let it dry fully, wet skin can sting. You do not need a separate needle; the pen contains its own. Our guide on injecting into the thigh covers the finer points of that specific site if it is your preferred spot.

Step 3: Inject and dispose safely

Remove the pen cap and follow the instructions in the Patient Information Leaflet that came with your specific device, since the exact mechanism varies slightly between pen formats. In general: place the pen tip flat against the skin (no pinching required for most adults), press the injection button, and hold it in place for several seconds until the dose indicator confirms the dose has been delivered. You will feel a small scratch. That is normal. Do not rub the site afterwards.

Needle disposal matters. Used injection devices contain a needle that poses a sharps hazard, and they must not go into your household bin. A sharps container keeps used pens safe until your local council or pharmacy accepts them for collection. This is not optional, it is a legal requirement under UK waste regulations. For more on the full injection process, our Wegovy injection walkthrough covers every step in one place.

A note on air bubbles, small bleeds and other common worries

A tiny dot of blood at the injection site is not a problem; press gently with a clean piece of gauze. Small air bubbles visible in a pre-filled pen are also normal and do not need to be expelled, the pen is engineered to deliver the right dose regardless. If you are curious about the detail behind this, our page on air bubbles in semaglutide devices explains the physics. What does need attention: if the skin around the site becomes noticeably red, swollen or painful over the following days, or if you experience symptoms elsewhere (severe stomach pain that radiates to the back, signs of an allergic reaction, or anything else that feels out of the ordinary) contact a clinician promptly. NHS England's guidance on weight management injections is a useful reference for the broader safety picture.

Semaglutide is a prescription-only medicine. The clinical assessment that precedes a prescription is not a formality, it establishes your starting dose, flags any interactions (oral contraceptives, for example, may be affected during the early weeks on tirzepatide, and your prescriber needs to factor this in), and sets up the aftercare you are entitled to. If you are considering starting treatment and want to understand the cost of Wegovy privately, or simply want to read more about the medicine itself, our Wegovy overview is a good place to start. Eligibility is assessed individually; a prescriber, not a set of tick boxes, makes the call.