Using the Wegovy 4-Dose Pen: What the Evidence and the SmPC Tell You

What the licensed guidance actually says about the 4-dose pen

The Wegovy pen is a pre-filled, pre-set subcutaneous injector. Each pen in the standard titration programme contains four doses at a single strength (0.25 mg, 0.5 mg, 1.0 mg, 1.7 mg or 2.4 mg) so you work through the programme one pen at a time, moving to the next strength only when your prescriber confirms it is appropriate. This graduated approach is there for a reason: the STEP 1 trial, published in the New England Journal of Medicine, showed that semaglutide 2.4 mg produced around 15% average weight reduction over 68 weeks, but participants followed a carefully titrated escalation, not a jump straight to the maintenance dose. The pen's counter tracks which injection you are on; once all four have been used, the device locks and cannot be reused.

A question our prescribers hear most weeks is whether it matters which day of the week you inject. It does, in the sense that consistency helps, but the day itself is your choice. Pick one that fits your routine and stick to it. If the day needs to shift by a day or two, that is generally fine provided at least 72 hours have passed since the previous injection; for anything beyond that, check with your prescriber rather than guessing.

For a broader picture of how the different strengths fit together across the programme, the Wegovy doses guide covers the full titration schedule.

Step-by-step injection technique for the Wegovy pen

Before each injection, check the solution through the pen window. It should be clear and colourless; discard the pen if it looks cloudy, discoloured or contains visible particles. Remove the pen cap just before injecting, not in advance. Clean the injection site with an alcohol swab and allow it to dry completely before the needle goes in.

Hold the pen against the skin at a 90-degree angle. Press the injection button firmly and keep it held down. You will hear a click when the dose begins; hold the pen in place for a full six seconds after that click so the complete dose is delivered. A second click may indicate the dose is finishing, but continue holding for the full six seconds regardless. Check the dose counter has returned to zero before removing the pen from the skin.

Rotation matters more than people realise. Injecting into the same spot repeatedly causes a build-up of fatty tissue that can slow absorption and reduce how consistently the medicine works. Rotate between the abdomen, thigh and upper arm, and within each area choose a slightly different spot each time. The abdomen tends to be the easiest site when starting out, particularly for self-injection.

For a comparison with the earlier lower-dose pens, the guide on using the 0.5 mg pen covers technique notes specific to that stage of titration. If you are moving up through the programme and have recently reached the 1 mg stage, our guide to using the Wegovy 1 mg pen walks through the technique and what to expect at that strength.

Storage, travel and what happens if a dose is delayed

Keep unused pens in the fridge between 2 °C and 8 °C, away from the freezer compartment and away from the back wall of the fridge where temperatures can dip below freezing. A frozen pen must be discarded. The pen currently in use may be kept at room temperature for a limited period, the exact window is stated in the patient information leaflet, and that figure should be your reference point, not a number found online, because it can differ between product batches and any updated leaflet supersedes older sources.

Travelling with Wegovy requires a little planning. A cool bag with an ice pack (not direct contact with ice) works for short journeys; pharmacies and travel clinics stock approved cooling wallets designed for injectable medicines. If you are flying, carry the pen in hand luggage with the original packaging and your prescription confirmation, as airport security occasionally asks for documentation.

If a weekly injection is delayed by a day or two, inject as soon as you remember and then return to your usual day. If the gap from the last injection is longer than that, contact your prescriber before injecting, the right course of action depends on how many doses you have had and where you are in the titration programme. The Wegovy multi-dose pen page also covers general device handling for anyone wanting a broader reference.

Side effects to be aware of at each dose stage

Most people experience some gastrointestinal symptoms when starting semaglutide or moving up a dose. Nausea is the most common; loose stools, stomach discomfort and fatigue are also reported frequently. These effects typically peak in the first few days after an injection and ease as the body adjusts over one to two weeks. They tend to return, more mildly, each time the dose increases. If you are using the higher-strength device and want a detailed walkthrough of the hardware itself, our guide to using the semaglutide 5 mg pen explains the mechanics and what the dose counter should show at each stage.

Practical steps that help include eating smaller portions than usual in the days after an injection, avoiding rich or fatty foods during adjustment, and keeping fluid intake up. Dehydration from persistent nausea or vomiting is worth taking seriously; if you cannot keep fluids down for more than a day, speak to a doctor or pharmacist rather than waiting it out.

Seek urgent medical attention for severe, persistent stomach pain that radiates to the back, this can be a sign of pancreatitis, which the MHRA has highlighted as an infrequent but serious risk with GLP-1 medicines. You can report any suspected side effect, including reactions you are uncertain about, through the MHRA Yellow Card scheme. The Wegovy overview page covers the full side-effect profile in more detail.

If you are considering whether Wegovy is the right treatment for your situation, the first step is a clinical assessment. Our prescribers review consultations the same day, and the free consultation page explains how the process works from start to finish.