- Semaglutide, STEP 1 extension: after stopping, participants regained roughly two-thirds of their prior weight loss within a year (from ~17% down to about 5.6% below starting weight).
- Semaglutide, STEP 4: people switched to placebo regained weight (about +6.9% over 48 weeks), while those who continued kept losing (about −7.9%).
- Tirzepatide, SURMOUNT-4: withdrawing the drug led to weight regain (+14.0%), while continued treatment kept weight off and reduced it further (−5.5%).
- Why: these medicines treat appetite and metabolism while taken; stopping largely reverses that effect.
- What helps: a clinician-led plan — maintenance dosing, a gradual taper rather than an abrupt stop, and strengthened diet, activity and support.
Why does weight come back after stopping?
GLP-1 receptor agonists such as tirzepatide (Mounjaro) and semaglutide (Wegovy) work by reducing appetite, slowing stomach emptying and changing how your body regulates hunger and fullness. Those effects last only while the medicine is in your system. When you stop, appetite signalling tends to return towards where it was before, and the body’s strong biological drive to regain lost weight reasserts itself. This is why doctors increasingly describe obesity as a chronic, relapsing condition — more like high blood pressure, where stopping treatment usually means the problem returns, than a short course of antibiotics.
Regaining weight after stopping is therefore an expected biological response, not a sign that you did anything wrong. Understanding this up front helps you and your prescriber plan realistically.
What the trials actually found
Three randomised trials give the clearest picture of what happens to weight when these medicines are stopped or maintained.
| Trial | Medicine | What was tested | Key result |
|---|---|---|---|
| STEP 1 extension (2022) | Semaglutide (Wegovy) | Weight after stopping treatment at week 68 | Regained ~two-thirds of lost weight; net loss fell from ~17% to about 5.6% one year later |
| STEP 4 (2021) | Semaglutide (Wegovy) | Continue vs switch to placebo after a 20-week run-in | Placebo group regained (~+6.9%); continued group kept losing (~−7.9%) over weeks 20–68 |
| SURMOUNT-4 (2024) | Tirzepatide (Mounjaro) | Continue vs switch to placebo after a 36-week lead-in | Withdrawal caused regain (~+14.0%); continued treatment lost further (~−5.5%) over weeks 36–88 |
In the STEP 1 trial extension, people who had lost an average of about 17% of their body weight on semaglutide were followed for a year after stopping. They regained roughly two-thirds of what they had lost, ending about 5.6% below their original starting weight. Related heart-and-metabolism improvements (such as blood pressure and blood sugar markers) also drifted back towards baseline.
The STEP 4 and SURMOUNT-4 maintenance trials show the mirror image: people who kept taking the medicine held onto their weight loss and often lost a little more, while those switched to a dummy injection began regaining. The direction of travel is consistent across both semaglutide and tirzepatide.
Does everyone regain all the weight?
No. On average people regain most — but not necessarily all — of what they lost, and there is real variation between individuals. Factors that appear to help hold weight down after stopping include keeping up regular physical activity (including strength training), higher-protein eating patterns, and ongoing behavioural or clinical support. None of these fully replaces the medicine’s effect for most people with obesity, but they can slow regain and protect some of your progress. The honest position in 2026 is that durable results without ongoing treatment are the exception rather than the rule, which is exactly why maintenance planning matters.
Maintenance: staying on, stepping down, or a maintenance dose
Because these are treatments for a long-term condition, many clinicians now frame the question not as “when do I stop?” but “how do I maintain?”. Depending on your situation, your prescriber might discuss:
- Continuing at your current dose if it is working, tolerated, and clinically appropriate — the trials show this is what best maintains weight loss.
- A maintenance dose — in some cases a lower dose that holds weight steady. Whether this works for you is an individual clinical judgement, not a fixed rule.
- A planned, gradual step-down rather than an abrupt stop, with monitoring and a plan to reinforce diet, activity and support as the dose comes down.
There is no single “correct” path, and MediWatch does not recommend a specific dose or schedule — that must come from the clinician who knows your history.
Why you should not just stop suddenly
The NHS advises: “talk to your doctor if you want to stop … and do not stop suddenly.” There are two reasons this matters. First, if you have type 2 diabetes, stopping can affect your blood sugar control, and your diabetes medicines may need adjusting. Second, an unplanned stop leaves you with no strategy for the appetite rebound that follows, which can make regain faster and more distressing. A clinician-led plan — whether that is continuing, tapering or switching approach — gives you the best chance of holding your progress.
Some people also stop involuntarily because of a supply shortage or cost. If that happens, do not simply ration or split doses on your own — speak to your pharmacist or GP, who can advise on alternatives and check official supply information.
What to do if you are thinking about stopping
- Book a conversation with your prescriber before making any change — ask about maintenance options, tapering, and a realistic plan for holding your weight.
- Ask what to expect so you are not caught off guard by returning appetite, and agree how progress will be monitored.
- Strengthen the non-drug foundations — regular activity including strength work, adequate protein, sleep and support — ideally before, not after, any dose reduction.
- Check supply if that is the trigger — a shortage or price change is a reason to talk to your pharmacist, not to stop abruptly.
Related reading
Mounjaro (tirzepatide) in the UK
Availability, price and how to access it.
Wegovy & Ozempic (semaglutide)
The difference and how to get them.
GLP-1 medicines & muscle loss
What weight loss means for lean mass.
Orforglipron (oral GLP-1)
The next-generation weight-loss pill.
Mounjaro supply status
Live UK supply signals tracked by MediWatch.
Wegovy supply status
Live UK supply signals tracked by MediWatch.
Track your weight-loss medicine's supply
MediWatch checks official DHSC and NHS data daily and alerts you if your medication is affected — so a shortage never forces an unplanned stop.
Search shortages free →Official sources: NHS: semaglutide (including how to stop) · NHS: tirzepatide
Trial evidence: Wilding JPH et al. “Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension.” Diabetes Obes Metab, 2022 (PMID 35441470) · Rubino D et al. “Effect of continued weekly subcutaneous semaglutide vs placebo on weight loss maintenance… STEP 4.” JAMA, 2021 (PMID 33755728) · Aronne LJ et al. “Continued treatment with tirzepatide for maintenance of weight reduction… SURMOUNT-4.” JAMA, 2024 (PMID 38078870). Figures are group averages; individual results vary.
MediWatch is not medical advice. Always follow your prescription label and ask a pharmacist, GP, specialist, NHS 111, or emergency services if you are unsure or unwell.