How to apply Wegovy: injection sites, technique and what actually happens

The biggest misunderstanding: self-injection is harder than it looks in the instructions

This is the concern our prescribers hear more than almost any other, that injecting yourself weekly will be frightening, painful, or technically demanding. In practice, the Wegovy pen is engineered to make self-administration manageable. The needle is fine and short (it reaches the subcutaneous layer without going deeper), the dose is pre-set so you cannot accidentally inject too much or too little, and the pen's mechanism does the hard part. Most people describe the sensation as a brief sting, sometimes nothing at all, particularly after the first few uses.

The Wegovy pen has a cap that must be removed before use. You hold the pen at a 90-degree angle against clean skin, press it firmly until it clicks, and keep it in place for a full ten seconds. A dose window or indicator on the pen changes to confirm the injection is complete. Semaglutide's clinical profile is well established, but technique is what makes delivery consistent week to week.

One practical note: the pen contains four weeks' worth of doses when new. Because Wegovy stays in the fridge, it is worth thinking about timing around holidays or trips away, a course starting on a Monday works well for most people, and planning around a one-month supply helps you spot any travel clashes early. If you prefer to reduce how often you think about reordering, ordering a three-month supply of Wegovy is a convenient option that suits many people with settled routines. The NHS semaglutide medicines page also covers technique and storage in accessible language.

Where on your body Wegovy can be injected

Three sites are approved in the Wegovy SmPC: the abdomen (belly), the outer thigh, and the upper arm. Each has practical advantages. The abdomen is usually the easiest to reach alone and gives you a good pinch of skin; the thigh works well seated; the upper arm is convenient but may need someone else's help to use consistently. All three produce equivalent absorption under clinical conditions.

The rule that matters most here is rotation. Using exactly the same spot every week leads to lipohypertrophy, a localised thickening of fatty tissue that can slow absorption and leave an uneven patch under the skin. Rotate within each site (a few centimetres from last week's spot) and alternate between sites across months. Avoid areas where the skin is broken, bruised, or affected by a rash. If you use insulin, do not inject Wegovy into the same area at the same time, though the sites themselves overlap.

If you are managing a feeling that Wegovy is losing effectiveness over time, technique and site rotation are among the first practical factors worth revisiting with your prescriber before assuming the medicine has stopped working. It is a more common cause than most people expect.

Preparing the skin and the pen: the steps that are easy to skip

Wash your hands before handling the pen. Clean the injection site with an alcohol swab and let the skin dry completely before injecting, alcohol that has not fully evaporated can sting more noticeably. Do not rub the skin after the injection; pressing gently is fine if there is slight bleeding, but rubbing can increase bruising.

Take the pen out of the fridge a few minutes before you plan to use it. A cold pen coming straight from 2°C tends to sting more at the site than one that has had ten or fifteen minutes to reach room temperature. The pen should never be frozen; if you are uncertain whether it has been, check the Patient Information Leaflet or the guidance on what to do if your supply is interrupted, the same source covers what happens if a pen has been stored incorrectly. The eMC (electronic Medicines Compendium) holds the full Wegovy Summary of Product Characteristics, which is the definitive authority on storage windows; your prescriber can also clarify these details.

Missed a dose? The standard guidance is to inject it as soon as you remember, provided the next scheduled dose is at least five days away. If it is closer than that, skip the missed one and resume your normal day. Never inject two doses to make up for one missed. For the full detail on missed doses, the NHS semaglutide page and the Patient Information Leaflet should be your first reference, and your prescriber is there precisely for situations like this. You can also browse our clinical FAQs for common questions about managing your treatment week to week.

Side effects connected to technique, and when to get medical help

Injection-site reactions (redness, mild swelling, itching at the spot) are among the most commonly reported effects in the early weeks. They are almost always self-limiting and tend to reduce as you build good rotation habits. If a reaction persists, worsens, or spreads beyond the injection area, contact your prescriber.

The broader side-effect profile of Wegovy is led by gastrointestinal symptoms: nausea, loose stools, indigestion, and occasional vomiting are most common around dose increases and usually settle within one to two weeks. Severe, persistent stomach pain that radiates to the back requires urgent medical attention, this can be a sign of pancreatitis, which the MHRA highlighted as an infrequent but serious risk in a Drug Safety Update issued in January 2026. If you experience that symptom, seek help the same day.

You can report any suspected side effect via the MHRA Yellow Card scheme, which accepts reports directly from patients. Supply-related concerns (for example, a pen that looks damaged or different from previous ones) should also be flagged there; the MHRA takes reports of suspect products seriously. For more on keeping your supply legitimate and uninterrupted, see our page on Wegovy supply in the UK. Wegovy is a prescription-only medicine; if you are ready to explore whether it could be right for you, check your eligibility with our prescribers.