Switching from Saxenda to Wegovy: what changes, what stays the same

Why do people switch from Saxenda to Wegovy in the first place?

Saxenda (liraglutide 3mg) and Wegovy (semaglutide 2.4mg) both work by activating GLP-1 receptors, slowing gastric emptying and reducing appetite. So if both medicines broadly work through the same pathway, why switch at all?

The most common reasons come down to convenience and results. A daily injection is a meaningful commitment over months or years; one injection a week is simply easier to maintain. Trial evidence also shows a meaningful gap in average weight loss between the two medicines. In the STEP 1 trial, semaglutide 2.4mg produced an average body-weight reduction of around 15% over 68 weeks, as published in the New England Journal of Medicine. Independent analyses of liraglutide 3mg in comparable populations typically show figures in the range of 5–8% over a similar period. That gap is why many people, often after a plateau on Saxenda, ask about moving across.

Some people also report that Saxenda's daily injection causes more day-to-day nausea variability than the once-weekly dosing pattern. That said, individual responses differ considerably, and neither medicine suits everyone. The timeline for Wegovy to show results varies from person to person, and a prescriber assessing you will want to understand what happened on Saxenda before recommending what comes next.

What does the switch actually involve, and is there a wash-out period?

This is the question our prescribers hear regularly, and it is worth answering precisely. There is no hard universal wash-out period mandated in Wegovy's UK prescribing information for patients switching from liraglutide; the approach is clinical and individual. Liraglutide has a half-life of roughly 13 hours, so it clears the system relatively quickly compared with semaglutide's half-life of around one week.

In practice, a prescriber may advise stopping Saxenda and starting Wegovy at its lowest dose (0.25mg weekly) without a gap, or after a short pause, depending on your GI tolerance and current liraglutide dose. Starting Wegovy at 0.25mg is standard regardless of what you were taking before, the titration schedule exists to allow your body to adjust, not to mark time. The NHS England guidance on weight-management injections makes clear that transitions between medicines in this class should involve clinical support throughout.

One practical point: if your Saxenda supply runs out mid-week and your Wegovy hasn't arrived yet, resist the instinct to bridge informally. Both the timing and the dose at which you start Wegovy matter, and that decision sits with your prescriber. Injection site rotation stays the same as before, abdomen, thigh or upper arm, rotated each week.

How do the two medicines compare side by side?

The table below sets out the key factual differences. Numbers from clinical trials are cited; individual results vary.

The MHRA approved a dedicated 7.2mg single-dose Wegovy pen on 14 April 2026 for adults with a BMI of 30 or above, with trials reporting an average weight loss of around 20.7% over 72 weeks at that dose. Specific dose and pen availability is confirmed at consultation rather than assumed in advance. You can read more about what to expect from Wegovy across the full dosing journey.

What should you expect in the first weeks after switching?

The most honest answer is: a reset of sorts. Even if you've been on a GLP-1 medicine for a year, starting Wegovy at 0.25mg means your body is meeting a new molecule at a new dose. Most people find the first four weeks fairly gentle, appetite suppression is mild at this stage, and GI side effects are typically less pronounced than they were when Saxenda was first started.

Nausea, loose stools or constipation can still appear, particularly around dose increases. The pattern with weekly dosing is that symptoms, if they come, tend to peak in the day or two after the injection rather than varying daily as they might have with Saxenda. That predictability helps some people plan around it, knowing Tuesday is the day to avoid a big lunch is easier than managing daily fluctuation.

Weight loss during the titration phase (roughly the first 16–20 weeks) is usually modest; the therapeutic effect builds as the dose increases. If you're wondering how your experience in week one compares with what's typical, our guide to week one on Wegovy covers that in detail. And if you ever decide to stop, knowing what to expect when stopping Wegovy matters just as much as knowing what to expect when you start Wegovy.

Which option is right for you, and whether switching now makes clinical sense, is a question our prescribers work through with each patient individually. Check your eligibility with a free consultation and a real clinician will review your answers the same day.