Forgot a Wegovy Dose: What Actually Happens and What to Do Next

The four-day rule: how to decide what to do right now

Wegovy works as a once-weekly injection, so missing one dose by a day or two is less disruptive than it sounds. The NHS medicines guidance for semaglutide is clear on the approach: if there are five or more days until your next scheduled injection, go ahead and take the missed dose whenever you remember it. If fewer than five days remain, leave it.

In practice, most people find it easiest to count backwards from their usual injection day. Say you inject every Monday and you realise on Thursday that you forgot, three days out from next Monday, that's fewer than five days, so you skip it. Same day next Monday, as always. No doubling up, no half-doses, no trying to split the difference. A single pen contains four weekly doses, each delivered through the Wegovy pen's pre-set mechanism, which is designed around that rhythm, and disrupting it gains you nothing.

Some prescribers phrase it slightly differently (four days versus five), because the licensed dose schedule for Wegovy allows a small window of flexibility around the injection day. The principle is identical: the closer you are to the next dose, the more sense it makes to simply wait. If you're unsure which version applies to your prescription, your Patient Information Leaflet or prescriber will confirm it.

Why skipping matters more than catching up

The temptation to inject twice in one week is understandable, but it's the wrong call. Taking two doses close together doesn't mean twice the effect, it means a sharply higher chance of nausea, vomiting, and the kind of gastrointestinal discomfort that makes people want to stop treatment altogether. Semaglutide has a relatively long half-life, which is exactly why a single weekly injection works; that also means a second dose on top of residual drug from the first creates an unintended spike.

Missing one dose occasionally won't undo your progress. The medicine continues to have some effect for several days after injection. One gap in seven weeks of consistent treatment is not the same as stopping. That said, if you find yourself regularly forgetting, it's worth building a small habit around it, some people link the injection to something fixed in their week, like a Sunday evening routine. The pen itself arrives in a plain, unbranded box from DPD, tracked to your door, so keeping it somewhere visible in the fridge can serve as its own reminder.

For more on how the treatment schedule fits together, the dose titration guide for Wegovy covers how each step builds on the last.

When a missed dose signals something worth discussing with your prescriber

One forgotten injection is one thing. Missing two or three in a row is different, and it's the situation where a quick conversation with your prescriber genuinely matters. After a gap of several consecutive weeks, the body's adjustment to semaglutide may have partially reset, and restarting at the dose you left off can bring back early side effects that you'd already moved past.

In that scenario, a prescriber might recommend restarting at a lower dose and retitrating, rather than jumping straight back to a higher strength; if you have been working toward the 2.7 mg stage of the Wegovy schedule, for example, your prescriber may advise stepping back before returning to it. This isn't a failure or a setback, it's just how the medicine works. The MHRA's Yellow Card scheme exists for reporting unexpected reactions, and it's worth knowing about if a missed-dose restart brings on symptoms that feel disproportionate.

If you're also taking other medicines (particularly oral contraceptives) Wegovy's effect on gastric emptying is relevant to absorption, so your prescriber should know about any significant gaps. The same applies if you're due surgery; your clinical team need to know you're on a GLP-1 medicine.

A fuller overview of how Wegovy works covers the mechanism and common questions about suitability. If you're transferring to us from another provider or want a fresh clinical review of where you are in your treatment, including whether you are ready to move to the 0.5 mg dose that begins the maintenance phase, checking your eligibility with our prescribers is a straightforward first step, the consultation is free, and a real clinician reads your answers the same day.

For context on the cost of ongoing treatment, the weight-loss treatment overview sets out what's included in a single transparent price.