For some people, weight-loss medication can produce substantial changes. A less comfortable question follows: what happens if treatment ends? In clinical trials of semaglutide and tirzepatide, participants who switched from medication to placebo regained weight on average. The findings do not predict exactly what will happen to any one person, but they challenge the idea that these drugs are necessarily short courses with lasting effects after they stop.
That distinction matters. Regaining weight after a medication is withdrawn is not proof that someone lacked willpower or that treatment failed. It is evidence about what happened in particular studies after a particular change in care. Decisions about continuing, changing or stopping medication are individual medical decisions, and the trials do not establish that everyone should take these drugs indefinitely.
What the semaglutide studies found
In the STEP 1 trial, adults with overweight or obesity, but without diabetes, received weekly semaglutide or placebo alongside lifestyle support for 68 weeks. The medication group lost an average of about 15% of body weight. Researchers later followed a subset of participants who had completed the trial and stopped both the medication and its structured lifestyle program.
During the year after treatment ended, those participants regained an average of 11.6 percentage points of body weight—roughly two-thirds of their previous average loss. At the end of that follow-up, their average weight remained below where it had been before treatment. Some health measures that had improved also moved back toward their starting levels. This was an exploratory follow-up, not a new randomized comparison, and it involved a subset of the original trial participants. It should not be read as a precise forecast for every person using semaglutide.
A separate study, STEP 4, tested withdrawal more directly. Participants first received semaglutide for 20 weeks and lost an average of 10.6% of their body weight. Those who continued into the next phase were randomly assigned either to keep taking the medication or to switch to placebo for 48 weeks. Both groups continued lifestyle counseling. On average, the group that switched to placebo gained 6.9% of its body weight during that phase, while the group that stayed on semaglutide lost a further 7.9%.
STEP 4’s design helps answer a specific question: among people who reached the randomized phase after taking semaglutide, what happened when the drug was withdrawn compared with continued treatment? It does not show what would happen to someone who stops for a different reason, or who has a different health history. Nor does it compare medication with every possible long-term support plan.
A similar pattern appeared with tirzepatide
The SURMOUNT-4 trial examined tirzepatide, another medication used for chronic weight management. Participants received the drug for 36 weeks before those who continued in the study were assigned either to remain on it or switch to placebo. During the initial treatment period, average weight loss was about 20.9%.
Over the following 52 weeks, participants who switched to placebo regained an average of 14.0% of their body weight, measured from the point of randomization. Those who continued tirzepatide lost a further 5.5% on average. Lifestyle counseling continued in both groups. As with STEP 4, the results describe the selected participants who reached the withdrawal phase—not everyone who might be prescribed the medication.
These trials are not interchangeable: they studied different medicines, schedules and groups of participants. But their broad message is alike. For many participants, stopping treatment was followed by weight regain, while continuing treatment was associated with maintaining or extending average weight loss during the study periods.
What the results can—and can’t—tell us
Weight is influenced by more than conscious choices. Appetite, the body’s regulation of energy, health conditions, medications, food access and daily circumstances can all matter. The trials show weight changes after a medication was withdrawn; they do not, by themselves, identify why each participant regained weight or prove that one mechanism explains everyone’s experience.
They also do not settle how long treatment should continue. A clinical trial has a defined follow-up period, and its averages can hide a wide range of individual outcomes. Some people may stop because of side effects, cost, a change in health circumstances or personal preference. Others may need a different treatment approach. The study results are useful context for those conversations, not a reason to treat ongoing medication as the only acceptable choice.
For anyone considering a change, a practical first step is to discuss it with the clinician who prescribes the medication. Ask what the benefits and risks of continuing are in your circumstances, what alternatives might fit, and what follow-up would look like if you stop. A plan can include monitoring weight and health measures, reviewing other medicines and conditions, and discussing nutrition and physical activity support. The exact approach should be individualized; a trial average cannot provide a personal stopping schedule.
These findings also put weight regain in perspective. If a treatment’s effect fades after it is removed, that does not erase the benefit it provided while it was being used. It means maintenance may require continuing care, whether that involves medication, other forms of support or a combination. The key question is not whether a person has enough discipline to keep weight off unaided. It is what sustainable, medically appropriate plan works for that person over time.
