How to use the Wegovy auto injector: a step-by-step guide

Step 1, Before you pick up the pen

Take the pen out of the fridge roughly 30 minutes before your planned injection. Cold semaglutide is perfectly safe to inject, but a pen at room temperature tends to be more comfortable. While it warms up, wash your hands thoroughly with soap and water. Check the label: confirm it is your strength, it has not expired, and the liquid visible through the window is clear and colourless. If the liquid looks cloudy, discoloured or contains particles, do not use it, contact your prescriber.

Choose your injection site. Wegovy is injected into the fatty tissue just beneath the skin of the abdomen (at least 5 cm from the navel), the front of the thigh, or the upper arm. Rotating sites each week reduces the risk of skin reactions at any single spot. The injection site diagram on our site maps these areas clearly if you want a visual reference. Clean the chosen area with an alcohol swab and let the skin dry fully before injecting, damp skin can sting.

Step 2, The injection itself

Remove the pen cap. You will see a small window confirming the dose and a coloured plunger indicator. Press the pen firmly and flat against your skin, do not angle it. A firm, steady press is the key; hovering or pressing at a tilt can prevent the auto-inject mechanism from triggering properly.

Press the button at the top of the pen with your thumb. You will hear or feel a click when the needle deploys, and a second click when the dose is complete. Keep the pen pressed to the skin until that second click and for a further five to ten seconds afterwards to make sure the full dose is delivered. Lift the pen straight off. The needle retracts automatically. There may be a small spot of blood or a tiny mark; this is normal. Do not rub the skin after injecting, as this can affect absorption. The entire process from button-press to pen removal takes roughly ten to fifteen seconds.

For a more detailed visual walkthrough of each stage, our guide on how to inject Wegovy covers the technique with annotated steps.

Step 3, Disposal, storage and keeping a schedule

Used pens are sharps waste. Place each pen directly into a sharps container immediately after use, do not recap the needle first or put it in a household bin. When the container is three-quarters full, seal it and take it to your local pharmacy or council-designated sharps disposal point. Putting sharps in general waste is illegal and puts refuse workers at risk.

Store unused pens in the fridge. If you are travelling, the pen can be kept at room temperature below 30°C for a limited period, but the exact window is stated in your Patient Information Leaflet, check that rather than relying on a general figure, because it varies by product version. For broader detail on what to expect from the Wegovy pen's design, including the auto-lock feature that prevents accidental re-use, our dedicated pen page explains the mechanism.

Consistency matters with a once-weekly medicine. Semaglutide takes time to reach steady levels in the body, so try to inject on the same day each week. If you miss a dose, follow your Patient Information Leaflet's guidance and raise it with your prescriber at your next check-in rather than doubling up. The semaglutide autoinjector format is specifically designed to make weekly dosing straightforward, but your prescriber is the right person to ask if your schedule goes awry.

Side effects to be aware of after injecting

The most common reactions are gastrointestinal: nausea, loose stools, constipation, indigestion or burping. These tend to be most noticeable in the days after a new dose level and usually ease as your body adjusts. Injection-site reactions (redness, itching, a small lump) are also reported, particularly if sites are not rotated.

More serious but less common effects include symptoms of pancreatitis: persistent, severe pain in the upper abdomen that radiates to the back, with or without vomiting. The MHRA highlighted this as a known risk in a Drug Safety Update in January 2026 and advises anyone with those symptoms to stop treatment and seek urgent medical attention. If you notice an allergic reaction (swelling of the face or throat, difficulty breathing) treat it as an emergency. You can also report any suspected side effects directly to the MHRA at yellowcard.mhra.gov.uk.

The NHS medicines page for semaglutide lists side effects by frequency and tells you which symptoms need same-day or emergency attention. Bookmark it before your first dose.

Thinking about what Wegovy costs as a private prescription? Our Wegovy cost page sets out what the market looks like and what a legitimate private price covers.

If eligibility, next steps or the consultation process is your next question, you can start your free consultation with our prescribers, every application is reviewed the same day by a real clinician, not an automated system.