Weight loss

What happens when you stop a GLP-1: what the trials found

By Juvenate Editorial Published October 24, 2026 Last updated October 24, 2026

Starting a GLP-1 medicine gets all the attention. Stopping one gets almost none, until it is suddenly your question. Maybe a prescription is ending, insurance has changed, side effects are wearing you down, or you simply wonder whether you can stop now that you have reached your goal. Two large, well-known trials looked at exactly this. Their findings are worth knowing before you talk to your prescriber.

This is not medical advice. Whether to continue, change or stop a medicine is a decision for you and your doctor or prescriber, and you should not stop or change anything on the basis of an article. No affiliate links. Disclosure.

Why the question matters

People stop GLP-1 medicines for many different reasons, and plenty of them are practical rather than medical. Because these medicines are often described as a way to “lose weight,” it is easy to assume the effect is permanent once the weight is off. The research suggests otherwise. The researchers behind one of the trials describe obesity as a chronic condition, and in both studies the benefits faded when treatment stopped.

That is not a judgment, and it is not a reason to feel stuck. It is simply useful information, and it helps you plan.

Trial 1: stopping tirzepatide (SURMOUNT-4)

In this study, published in JAMA in 2024, 783 adults with obesity, or overweight with a weight-related health problem, and without diabetes, took tirzepatide at the maximum tolerated dose for 36 weeks. They lost a mean of 20.9% of their body weight.

Then 670 of them were randomly assigned, in a double-blind way, either to continue tirzepatide or to switch to a placebo for another 52 weeks. Here is what happened between week 36 and week 88:

Continued treatment: weight changed by an additional −5.5% on average.
Switched to placebo: weight rose by 14.0% on average.
Kept at least 80% of their lead-in weight loss: 89.5% of the continued group versus 16.6% of the placebo group.

Even so, the placebo group did not return to where they started. Measured from the very beginning of the study, their average weight reduction at week 88 was 9.9%, compared with 25.3% for the people who stayed on treatment. The authors concluded that withdrawing tirzepatide “led to substantial regain of lost weight,” while continued treatment maintained and added to the initial loss.

Worth knowing: the trial was sponsored by the drug’s manufacturer, as is typical for studies like this, and it was in adults without diabetes. These are averages, so individual experiences vary widely.

Trial 2: stopping semaglutide (STEP 1 extension)

In the original STEP 1 trial, 1,961 adults with obesity or overweight (without diabetes) took semaglutide 2.4 mg or a placebo for 68 weeks, alongside a lifestyle program. The semaglutide group lost a mean of 17.3% of their body weight.

At week 68, treatment, including the lifestyle program, was stopped. A subset of 327 participants was followed for one more year without treatment. By week 120:

The semaglutide group had regained 11.6 percentage points of their lost weight, on average, and ended about 5.6% below their starting weight.
The placebo group had regained 1.9 percentage points and ended essentially where they started.
The improvements in cardiometabolic measures (the kind of markers doctors track) seen during treatment reverted towards baseline for most variables.

The researchers concluded that participants regained about two-thirds of their prior weight loss within a year, and that their findings “confirm the chronicity of obesity and suggest ongoing treatment is required to maintain improvements in weight and health.” One important caveat is that all of the analyses in this extension were exploratory, so treat the numbers as informative rather than final.

What these trials do not tell us

It is easy to read too much into two studies, so here is what they cannot answer:

They measured averages. Some people regained less, and some regained more.
They did not test every way of stopping. Both studies stopped treatment, and the STEP 1 extension stopped the lifestyle program too. They do not tell you what happens if a person changes their medicine, adjusts their plan with a doctor, or builds new habits first.
They were in adults without diabetes. People with diabetes, or those taking other medicines, may have different experiences and different risks.
Their published summaries do not address skin, hair or muscle after stopping. We did not find data on that in what we reviewed, so we will not guess.

Questions worth asking your prescriber

If you are thinking about stopping, or you may have to, consider bringing these to your next appointment:

What are my goals, and what would you like me to track after any change, such as weight, blood pressure, blood sugar or cholesterol?
If I need to stop because of cost, supply or side effects, what are my options? Are there other approved treatments I could discuss?
What should I change in my eating, activity and sleep, so I am supported through the transition?
Is there a follow-up plan, and when should I check in if my weight or appetite changes?
If I am considering pregnancy, or my health situation is changing, how does that affect the plan?

Please do not turn to unregulated sellers because of cost or supply pressure. If access is the problem, ask your prescriber or pharmacist what legitimate options exist.

What may still help, regardless

Whatever you decide with your prescriber, a few basics are worth keeping steady:

Protein and nutrition. See our protein guide for the research behind it.
Movement and strength. Both trials paired treatment with diet and activity support, and these habits are within your control whatever the medicine decision.
Skin and hair care. Our posts on healthy aging on a GLP-1 and Ozempic face and skin changes cover what you can do.

You can also download our free GLP-1 Glow-Up Guide, which gathers the basics on protein, skin, hair and sun protection in one place.

The bottom line

In two large trials, people who stopped a GLP-1 medicine regained much of the weight they had lost, and health markers that had improved moved back toward where they started. That is not a failure of willpower. It is what the studies repeatedly show. If you are considering stopping, or have to, the most useful step is a planned conversation with your prescriber, ideally before any change.

For more, visit our GLP-1 page.