Former GLP-1 users regain lost weight after about 18 months, study says

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• Researchers analyzed 37 studies on how people coped after coming off weight-loss medications, although only six of the studies were on semaglutide and tirzepatide – among the most widely prescribed categories of weight-loss drugs.
• People who come off the popular drugs Ozempic, Wegovy and Zepbound are projected to return to their baseline weight after an average of 18 months.
• When looking at a total of 13 weight-loss medications, users were projected to return to their baseline weight after 20 months – still about four times faster than someone coming off a behavioral program such as a diet.
• In addition to regaining weight, people returned to pre-drug levels of key markers of cardiometabolic health – including blood pressure and cholesterol – about 17 months after coming off all weight-loss drugs.

The peer-reviewed paper, published Wednesday in the British Medical Journal, analyzed 37 studies following 9,300 participants on 13 weight-loss medications.

People who take the most common categories of weight-loss drugs, semaglutide and tirzepatide, marketed as Ozempic, Wegovy and Zepbound, tended to lose about 33 pounds during their treatment but then regained about 22 pounds in the first year after stopping, Sam West, a physiology researcher at Oxford University who co-wrote the study, said in a phone interview Thursday. “What was particularly striking in our data was just how fast it was regained,” he said.

Whereas previous estimates suggested people regained weight lost on semaglutide or tirzepatide within two or three years, West said the analysis put the timeline at just 18 months. (In Britain, where West is based, government guidance estimates the weight would be regained after about three years.)

Giles Yeo, a professor of genetics at Cambridge University who specializes in food intake and did not work on the study, said the findings were not surprising. Many people forget that GLP-1s are drugs like any other, he said in a phone interview Thursday. “And like most drugs, with the exception of vaccines, they typically only work when you’re on them,” he said.

Yeo compared the drugs to medication for high blood pressure. “When your blood pressure is normalized, no one ever says, ‘Gee, I’m going to now stop taking my pill.’ Because what happens if you stop is, almost immediately, your blood pressure will become abnormal again. Now, clearly it takes longer to regain weight, but the same is going to be true for these weight-loss drugs.”

Yeo also cautioned that the study had a number of limitations and said more research is needed. Only a fraction of the reviewed studies focused on semaglutide, which he pointed out are among the most commonly prescribed categories of weight-loss drugs. In addition, none of the trial-based data used in the surveys extended beyond 12 months, meaning any longer-term projection is just an estimate.

Given so many people are taking these drugs, Yeo said, he expects longer-term trial data to emerge in the coming years that will provide a more certain picture.

The review underscores our existing understanding that it is difficult to maintain weight loss after coming off such injections. One study in 2022, for example, found that participants had regained about two-thirds of their prior weight loss about a year after coming off a weekly semaglutide injection – roughly in line with the review’s averages.

As millions of Americans use GLP-1s, scientists expect an increasing focus in the coming years on how users can maintain their weight loss. Studies have shown that as many as half of users quit the drugs within a year because of their cost, unwanted side effects or other reasons.

In response, Yeo said, pharmaceutical companies are experimenting with ways to use the weight-loss drugs to help people maintain their weight, rather than just lose it.

“This could involve a mixture of lowering the dose; decreasing the number of injections that are required; or oral versions of the drugs, which typically are going to be less effective but are probably going to be perfectly fine for weight maintenance,” he said.

When you lose weight, your body naturally fights against it by suppressing how many calories you burn and increasing your hunger drive, West said. Weight-loss medications are effective because they suppress those feelings of hunger.

But that also means that when you stop taking the medication, the cravings for food are probably going to roar back. “Those are ultimately going to drive weight regain if you’re not able to control those feelings,” West said.

But weight-loss medications can pave the way for more sustainable strategies to keep the weight off: namely, exercise and an improved diet.

One long-term study in 2024 found people who exercised while using a weight-loss drug kept off far more pounds after quitting the medication than people who didn’t work out.

Yeo suggests thinking about weight-loss drugs as a tool for people to build healthier lifestyles while they are on them, with the goal of making it easier to come off the drugs and maintain the weight. “I’m not saying this is easy, but you now have a set of tools, recipes, habits, a new bicycle route to work, that you can just call upon when the going gets tough.”