Your Wegovy pen didn't click twice — here's what's likely happened

Picture the moment: pen against your skin, first click, then silence

You've followed the steps. Pen held against your thigh or abdomen, skin pinched, button pressed firmly. The first click fires cleanly and you hold the pen in place, counting. But the second click never comes, or it was so faint you can't be sure it happened. Your hand drops and now you're left looking at the yellow plunger window wondering whether ten days of careful storage and a week's worth of medicine just went to waste.

That pause of uncertainty is the thing our prescribers want to address, because what you do in the next few minutes matters. The worst outcome isn't a missed click, it's pressing the button again because you assumed nothing went in, and inadvertently doubling your dose.

So before anything else: do not re-inject. Hold the pen still, check the window, and then work through the points below.

The yellow plunger (the narrow rod visible through the clear dose window on the side of the pen) should have moved to the bottom of the viewing area once the full dose has been expelled. If it has moved to the base of the window, the dose is very likely to have been delivered regardless of whether you heard the second click. You can do this check in under a minute, and it's the single most reliable on-the-spot indicator you have. The guide to Wegovy pen clicks covers each stage of the sequence in detail if you'd like a side-by-side walkthrough.

Why the second click sometimes doesn't register, the mechanics behind the pen

The Wegovy auto-injector is a spring-loaded device. When you press the button, the mechanism drives the needle in and simultaneously begins pushing the plunger through the cartridge to expel the medicine. The second click is produced by the mechanism reaching its end-stop, the physical point at which the plunger has travelled its full distance and the spring has discharged completely. NHS guidance on semaglutide recommends holding the pen firmly against the skin for at least ten seconds after pressing the button, precisely because releasing early is the most common reason the second click is muffled or missed entirely.

Several things muffle or prevent that second sound from reaching your ear. Thick clothing or fabric held against the injection site absorbs the vibration. If the pen is pressed at an oblique angle rather than straight on, the mechanism may not seat cleanly. Injecting into an area with more subcutaneous tissue can dampen the sound. Ambient noise (a television, a running tap) masks it. And occasionally, particularly in cold conditions (the pen should always return fully to room temperature before use, per the Patient Information Leaflet), the mechanism moves more slowly, making the second click quieter and less crisp than expected.

None of these scenarios means the dose wasn't delivered. They mean the auditory signal was compromised. The plunger window remains your most reliable check when the sound leaves you uncertain. That said, if the plunger window shows the rod has not moved, the dose has not been expelled, and in that case, you need to contact your prescribing team before doing anything else.

For those who've had a different kind of injection uncertainty (not hearing or feeling much at the site) the page on not feeling the Wegovy injection addresses the sensation side of things separately.

What you should and shouldn't do after an uncertain second click

The most important rule is the one already stated: do not press the button again on the same pen or attempt a second injection with a new pen. Semaglutide at 2.4 mg is already the maintenance dose arrived at after a careful titration schedule, and a double dose substantially increases the risk of serious gastrointestinal effects, nausea, vomiting and diarrhoea that could tip into dehydration. There is no clinical rationale for injecting twice in one day, and if you're also wondering whether injecting semaglutide twice a week is ever appropriate, the answer is no: once weekly is both the licensed schedule and the clinically safe one.

Check the plunger window immediately, while the pen is still in your hand. If the yellow rod is at the base of the window: in all likelihood the dose was delivered, the second click was simply inaudible. Note what happened, tell your prescriber at your next review, and carry on with your usual weekly schedule.

If the plunger has clearly not moved, or you cannot tell: contact your prescribing team the same day. Do not guess. A prescriber can advise whether a same-day injection is appropriate, which depends on the dose you're taking, how long you've been on treatment, and other factors that sit firmly in clinical territory, not in a checklist. At nume, our aftercare team is available seven days a week for exactly this kind of question; you can reach us via the contact page.

Dispose of the pen in a sharps container once you're done, whether the dose was successfully delivered or not. Used pens should never go into household bins.

For context on how Wegovy fits into a broader weight-management approach, the Wegovy overview page covers the treatment in full, including how it's prescribed through a regulated UK service.

When to seek medical help and who to call

Most cases of an uncertain second click are resolved by a plunger-window check and a message to your prescribing team. But there are situations that warrant a different response.

If you experience severe or persistent nausea, vomiting, or stomach pain after an injection (particularly pain that radiates through to your back) seek medical attention promptly. The MHRA highlighted acute pancreatitis as an infrequent but serious risk with GLP-1 medicines in a safety update in January 2026, and severe stomach symptoms should never be waited out at home. Signs of an allergic reaction (swelling of the face, lips or throat, difficulty breathing, rapid heartbeat) are a 999 situation.

If you're uncertain about any aspect of your treatment (click counts, injection technique, what to do if you miss a dose) your prescribing team is the right first call, not an internet forum. A common question our team receives is whether you can prime the Wegovy pen twice, and the short answer is that you should not, as priming more than once wastes medicine and can affect your dose. Questions about technique that come up regularly are also addressed in the FAQs. And for those thinking about starting Wegovy or exploring how semaglutide-based treatment compares with other options, the weight-loss treatment overview is a useful starting point before a consultation.

Wegovy is a prescription-only medicine; everything about how you use it, adjust it or troubleshoot it should ultimately go through a qualified prescriber. If you're not yet a patient and would like a clinical assessment, you can start your free consultation with our prescribing team.