What Happens When You Stop a GLP-1: What the Trials Found
2026-11-06 · 5 min read · GLPcompare Editorial
Short answer: most people who stop a GLP-1 regain weight. One year after stopping semaglutide 2.4 mg in the STEP 1 trial extension, people had regained two-thirds of the weight they had lost. In SURMOUNT-4, people who switched from tirzepatide to placebo gained back 14% of their body weight over a year, while those who stayed on it lost another 5.5%. These are averages across trials: what happens to one person varies widely, and this is not advice to stay on or stop a medicine. Talk to your clinician before changing either.
What each trial measured
Three randomized trials tested stopping directly. In each one everybody took the medicine first, then some were switched to placebo without knowing it.
| Trial | Medicine | First phase | After the switch: stayed on | After the switch: placebo |
|---|---|---|---|---|
| STEP 4 | Semaglutide 2.4 mg | 20 weeks, lost 10.6% | Lost a further 7.9% by week 68 | Gained 6.9% by week 68 |
| SURMOUNT-4 | Tirzepatide, highest tolerated dose | 36 weeks, lost 20.9% | Lost a further 5.5% by week 88 | Gained 14.0% by week 88 |
The STEP 1 extension followed 327 people after the trial ended, with no one on the medicine. They had lost 17.3% on semaglutide by week 68 and regained 11.6 percentage points by week 120, leaving a net loss of 5.6%.
A 2026 systematic review pooled 17 studies with 3,793 people who stopped, and found an average regain of 7.2% of body weight, with 13% after tirzepatide, 7.2% after semaglutide 2.4 mg and 4.8% after liraglutide 3 mg. Its authors note that regain tracks how much the medicine took off in the first place, and the studies differ widely in length and method, so treat these as rough figures.
It is not only the weight
In the STEP 1 extension, the improvements in cardiometabolic measures seen on treatment went back towards where they started for most measures by week 120.
A 2026 analysis of SURMOUNT-4 in JAMA Internal Medicine grouped 308 people who stopped tirzepatide by how much they regained. The more they regained, the more waist size, blood pressure, cholesterol and A1c moved back. Among those who regained 75% or more of the weight they had lost, waist size rose by 14.7 cm and systolic blood pressure by 10.4 mm Hg, against 0.8 cm and 6.8 mm Hg among those who regained under 25%. It was an analysis after the fact and cannot prove what caused what.
Who keeps the weight off?
Not everyone regains it all, and the same analysis shows the range: of those 308 people, 54 regained less than a quarter of what they had lost and 74 regained three-quarters or more. In SURMOUNT-4, 16.6% of those on placebo kept at least 80% of their loss at week 88, against 89.5% of those who stayed on tirzepatide.
The trials above do not say which people will keep it off, or whether a slower step-down of the dose changes the outcome. None of them tested tapering.
How long the medicine stays in your body
Each FDA label states how long the drug takes to leave the body, which is why stopping does not feel immediate:
- Semaglutide: half-life of about a week. It stays in circulation about 5 to 7 weeks after the last dose of Wegovy and about 5 weeks for Ozempic.
- Tirzepatide: half-life of about 5 to 6 days for Zepbound, and about 5 days for Mounjaro.
- Dulaglutide: half-life of about 5 days.
- Orforglipron: half-life of about 29 to 49 hours.
- Liraglutide: half-life of about 13 hours.
Stopping for a reason: pregnancy and surgery
Each label has its own wording, and these are the cases people ask about most.
- Pregnancy. The Zepbound and Foundayo labels say to stop when a pregnancy is recognized. The side effects page for each brand quotes its label's section on pregnancy.
- Surgery and anesthesia. Labels warn of rare reports of pulmonary aspiration in people on these medicines under general anesthesia or deep sedation, and say the data are insufficient to recommend whether stopping beforehand reduces the risk. Tell the team doing the procedure that you take one.
If cost is why you are stopping
Price is one common reason people come off, and it has changed quickly. FDA-approved self-pay prices start at from $149/mo for the Wegovy pill at its lowest dose. Compare every current price, read what each medicine costs if you lost coverage, or see the price at each dose before deciding, and ask your clinician about a lower dose.
Common questions
Do you have to take a GLP-1 forever? The trials show regain after stopping, not that everyone must stay on one for life. How long to treat is a decision for you and your clinician. The authors of the STEP 1 extension conclude the findings suggest ongoing treatment is needed to maintain the improvements.
How fast does the weight come back? In STEP 4 and SURMOUNT-4 the placebo groups were measured about 48 to 52 weeks after the switch. Those trials report the change over that period. Their summaries do not give a month-by-month rate.
Are there withdrawal symptoms? The FDA labels do not list a withdrawal syndrome. They describe side effects while taking the medicine, and these trials report the return of weight and metabolic measures. If you feel unwell after stopping, tell your clinician.
Does switching to another GLP-1 count as stopping? Not in these trials: they compared staying on one medicine with placebo. Labels say not to take two GLP-1 medicines together.
Sources
Every figure above links to its source. The FDA label for Zepbound reports the same withdrawal trial, and each brand's side effects and dosing pages quote its label. The trials are at STEP 4, STEP 1 extension, SURMOUNT-4 and the JAMA Internal Medicine analysis. This article is information, not medical advice.