How long does Wegovy stay in your system after you stop?

Why does semaglutide take five weeks to leave your system?

Semaglutide is a large-molecule GLP-1 receptor agonist designed to act slowly. Its half-life of roughly seven days is intentional, it's what allows a single weekly injection to keep appetite suppression steady across the whole week rather than spiking and crashing. The maths of half-lives means that after five half-lives (five weeks), less than 3% of the medicine remains in circulation. At that point it's considered pharmacologically cleared.

This long half-life is a feature when you're on treatment: missing one injection by a day or two rarely causes a dramatic drop in effect. But it also means that when you stop, the medicine doesn't vanish overnight. Effects taper over weeks, not days. Some people notice their hunger starting to return around week two or three; others feel the shift more strongly at week four. There's individual variation depending on body weight, kidney function and how long you'd been on treatment.

The detailed pharmacokinetics of semaglutide clearance follow the same five-week pattern regardless of which dose you were on when you stopped, higher doses don't clear faster, they just have more medicine to work through.

What actually happens to your body during those five weeks?

One misconception worth clearing up gently: stopping Wegovy does not cause a sudden rebound where everything rushes back at once. The taper is gradual. Gastric emptying (the slowing of food moving from your stomach to your intestines) returns to its previous pace as semaglutide levels fall. Appetite signals from the brain increase incrementally. Most people describe it as hunger quietly turning the volume back up over several weeks.

What this means practically is that the five-week clearance period is a window. If you're stopping because of a planned surgical procedure, for instance, your healthcare team will want to know you're on a GLP-1 medicine, and the five-week window is relevant to that conversation. If you're stopping to try to conceive, the MHRA advises using contraception while on GLP-1 medicines and for a wash-out period before conception; your prescriber will confirm the timing that applies to you. If you want a fuller picture of how long Wegovy stays in your system and what that means day to day, we've covered the topic in detail.

The NHS medicines page for semaglutide is the clearest patient-level resource for understanding what to expect when you stop, including what side effects may ease and which symptoms warrant medical advice.

What does the evidence say about weight after stopping?

This is where the clinical picture is worth understanding honestly. The STEP 1 trial, published in the New England Journal of Medicine, showed that participants who stopped semaglutide after 68 weeks regained a substantial portion of their lost weight within the following year, alongside a return of the cardiometabolic improvements the medicine had produced. The effect of the drug is real; so is its dependence on continuation.

None of this means treatment must be lifelong for everyone, but it does mean stopping isn't a neutral act. Wegovy's NICE recommendation (TA875) notes a maximum treatment duration of two years within specialist services on the NHS, but private prescribing decisions are made individually. If you're weighing up what stopping looks like for you, that conversation belongs with a prescriber who knows your history, not a forum.

For context on what private treatment involves, the Wegovy private treatment cost overview covers what a full course typically includes. And if you're still early in your thinking about whether Wegovy is right for you, the Wegovy treatment page sets out the licensed indications and how the medicine works.

Does the five-week rule change if you're switching to Mounjaro?

People switching from Wegovy to Mounjaro (tirzepatide) sometimes ask whether they need to wait for full clearance before starting. The short answer is that it depends on clinical judgement, not a fixed rule. Both medicines act on GLP-1 receptors, and your prescriber will consider whether an overlap or a wash-out period is appropriate for you. Overlapping two GLP-1 pathway medicines isn't standard practice; a brief gap is more common.

The five-week clearance figure is therefore a useful reference point for planning, but it isn't automatically the gap your prescriber will recommend. Timing decisions around switches, pauses and restarts should always be made with clinical input. Our prescribers review every case individually, you can read more about the semaglutide clearance timeline or, if you're ready to talk through your options, check your eligibility with the team.