You've just used your Wegovy pen — here's what happens next

The moment the injection finishes: what your pen is telling you

You've held the pen against your skin, pressed the button, and heard (or felt) the click. Now what? The first thing to check is that the dose window has changed, on the Wegovy pre-filled pen, a yellow indicator moves to confirm the injection is complete. If it hasn't moved, the dose may not have been fully delivered. Gently press the pen more firmly to the skin and hold it there for a full ten seconds before removing it; that dwell time matters more than most people realise.

Once the pen is away from your skin, look at the injection site. A small dot of blood or a tiny bruise is normal, the needle gauge is fine and subcutaneous tissue bleeds a little. Press gently with a clean finger for a few seconds. Do not rub: rubbing can push medicine back out of the tissue and alter absorption. You do not need a plaster unless you are on blood thinners, in which case your prescriber will already have discussed this with you.

If you are not sure whether the dose landed, the safest move is to call your prescriber or pharmacist before opening another pen. Taking two doses in one week significantly increases the risk of nausea, vomiting and dehydration. The full step-by-step injection technique covers what to check before you even uncap the pen.

What to do with the pen itself, and why the bin is not an option

This is where a lot of people get caught out. The used pen contains a needle that has been inside your body. Even after the mechanism locks, the tip is contaminated and sharp enough to puncture skin through a standard bin bag. UK guidance is clear: all sharps generated at home (including injector pens) go into an approved sharps container, not general waste, recycling, or a drinks bottle.

Your local council manages sharps disposal for home users. Most provide a yellow sharps bin on request, often for free or a small fee, and collect it kerbside or at a drop-off point. Pharmacies, including some GP surgeries, may also accept filled containers. The practical habit that takes under a minute: as soon as the pen comes away from your skin, put it straight into the sharps container before you do anything else. Don't set it down on the counter to deal with later, later becomes a week, and then the container is full and the loose pen is still on the bathroom shelf. One motion, one place.

For the container itself, a 1-litre sharps bin is suitable for most patients going through one pen per week; check whether your council collects this size. More detailed guidance on disposal routes is on our Wegovy pen disposal page.

Rotating injection sites and keeping a record

After disposal, the last step is to note where you injected. Semaglutide is given subcutaneously (into the fat layer just under the skin) and the licensed sites are the abdomen (avoiding the two inches around the navel), the front of the thigh, or the upper outer arm. Rotating between and within these areas prevents lipohypertrophy: a build-up of fatty tissue that forms when the same small patch of skin is repeatedly punctured. Lumpy tissue doesn't absorb medicine evenly.

A simple rotation log takes seconds. Some people use a notes app; others draw a rough body diagram and tick boxes. Either works. What matters is not injecting the same spot two weeks running. If you notice a firm or raised area under the skin where you usually inject, mention it to your prescriber, they will advise whether to avoid that area while it recovers.

The Wegovy treatment overview has more on how the weekly injection schedule fits into the broader treatment plan, and the semaglutide injection uses page explains the clinical basis for how the medicine works once it's absorbed. Side effects (particularly nausea that tends to peak in the first day or two after each dose) are covered in detail by the NHS semaglutide patient information page, which is worth bookmarking for reference.

When something doesn't feel right after an injection

Most post-injection reactions are minor: a little soreness, mild nausea by the evening, occasionally a headache. These are well-documented effects of GLP-1 medicines and generally ease as your body adjusts to each dose level. But some symptoms warrant prompt attention.

Severe abdominal pain (particularly pain that spreads to your back and doesn't settle within a few hours, with or without vomiting) should be assessed urgently. The MHRA highlighted acute pancreatitis as a known, though uncommon, risk with GLP-1 medicines in a Drug Safety Update in January 2026; persistent severe stomach pain is the key warning sign. Go to A&E or call 111 rather than waiting to see if it passes. Signs of a serious allergic reaction (swelling of the face, throat or tongue, difficulty breathing, rapid heartbeat) also need emergency care.

For everything else (uncertainty about the dose, questions about your next injection, side effects that are affecting your daily life) our prescribers are reachable through aftercare support seven days a week. You can also report any suspected side effect directly through the MHRA's Yellow Card scheme, which helps build the ongoing safety picture for these medicines. If you are based in West Yorkshire and considering starting treatment, you can find out more about Wegovy injections in Leeds and whether the service suits your situation through a free consultation with our clinical team.