Missed Your Wegovy Shot by One Day? Here's What the Guidance Says

Why the pharmacology makes a one-day slip far less significant than it feels

Semaglutide, the active ingredient in Wegovy, has a biological half-life of roughly one week in the body. That unusually long half-life is the reason one weekly injection is enough to maintain a steady therapeutic level. The practical consequence for a missed dose: a 24-hour delay produces a much smaller dip in the medicine's concentration than most people expect. The STEP 1 trial published in the New England Journal of Medicine demonstrated the weight-management effect of semaglutide 2.4 mg across 68 weeks, that sustained effect depends on consistent weekly dosing over time, not on injecting at exactly the same hour each week.

None of this means timing can be ignored indefinitely. The clinical rule (take the late dose if your next injection is still at least two days away) exists to prevent two doses being given too close together, which would produce a sharper spike in exposure and raise the risk of gastrointestinal side effects. One day off schedule does not create that problem. Take the dose, then return to your usual weekly day going forward.

If you want to understand the full dose schedule and how each strength fits into treatment, the Wegovy doses guide on our site covers the titration pathway in plain language.

What to actually do when you realise you are one day late

The steps are short. Check when your next injection would normally fall. Count the days: if there are two or more days between today and that date, go ahead and take the missed dose now, then keep the same weekly day for every injection after this one. If there is less than two days to your next scheduled dose, skip this one entirely and continue from the next planned date. Do not inject twice in quick succession to compensate.

After taking the late dose, watch for any gastrointestinal symptoms that feel heavier than usual. Nausea, loose stools and stomach discomfort are the most common side effects of Wegovy (listed clearly in the NHS semaglutide patient information) and they can occasionally flare after a short interruption, particularly if you are still in the earlier weeks of treatment. These effects normally settle within a day or two.

If you have been late before or find your schedule hard to keep, it may be worth reading our advice on what to do when you have missed one week of Wegovy, which explains how to get back on track when a gap has stretched further than a single day. Consistency in timing is not pharmacologically critical, but a reliable anchor makes accidental gaps much less likely.

When a one-day gap becomes something to discuss with a prescriber

One day is the easy case. Difficulty arises when a missed dose is part of a pattern, or when other circumstances complicate the decision. If you are unwell with vomiting or severe diarrhoea around the time of a missed dose, the interaction between illness and the medicine's gastrointestinal profile is worth flagging before you reinject. Similarly, if you have recently changed your injection day and are unsure whether today counts as one day late or nearly two weeks early, contact your prescriber rather than guessing.

There is also the question of what happens if more time passes. A one-day gap sits at the comfortable end of the spectrum; the guidance changes when the delay reaches three days or more. Our page on missing a Wegovy dose by three days explains where the threshold sits and what the adjusted advice looks like. For anything beyond a week, the picture changes more significantly, see the guidance on missing two consecutive Wegovy doses.

We know it is easy to feel anxious when something in a treatment routine slips, especially if you have only recently started and are still finding your feet. A one-day delay is genuinely one of the less consequential things that can happen on this treatment. Acknowledge it, act on the guidance above, and move on.

What this means for the rest of your treatment

After taking today's late dose, your next injection should fall seven days later, not six, not eight. Resist the instinct to adjust back to the original day immediately; that can create an unintended short interval. If your original injection day was, say, a Monday and you have now injected on a Tuesday, keep Tuesday as your new anchor day, or speak to your prescriber if you want to return to Monday in a controlled way. The full missed-dose guide for Wegovy covers how to handle that kind of day-change decision.

Treatment continuity matters. For context on how Wegovy fits into the broader range of options available to you, the weight-loss treatment overview on our site sets out what is licensed and how different approaches compare. Questions about the cost of ongoing Wegovy treatment are addressed separately on our Wegovy cost page.

If you would like a prescriber to review your situation directly (whether it is about this missed dose, a pattern of disrupted timing, or anything else about your treatment) speak to our prescribers via a free consultation. A real clinician reads every submission the same day.