In recent years, new weight-loss drugs have become very popular. These medicines, known as GLP-1 agonists, are injectables that help people feel less hungry and lose a lot of weight—often between 15 to 20 percent of their total body weight.
They have changed how doctors treat obesity and diabetes in many parts of the world.
But a new study shows that when people stop taking these drugs, they gain back the weight much faster than people who lose weight through diet and exercise. In fact, the weight comes back four times faster.
Researchers from Oxford University, including public health expert Susan Jebb, recently published a large study in the British Medical Journal (BMJ).
They looked at 37 studies that followed people who stopped taking weight-loss drugs. One of their key findings was that these people gained back about 0.4 kilograms (nearly a pound) every month after stopping the medicine.
Some of the studies focused on semaglutide, the main ingredient in the popular drugs Ozempic and Wegovy, and tirzepatide, used in Mounjaro and Zepbound. People taking these drugs lost an average of nearly 15 kilograms during the treatment.
But after they stopped, they gained back around 10 kilograms in just one year. That was the longest follow-up time available, as these drugs are still quite new.
The researchers estimated that most people would return to their original weight within 18 months of stopping the drug. They also found that improvements in heart health—like better blood pressure and cholesterol levels—also disappeared about 1.4 years after stopping.
In comparison, people who lost weight through diet and exercise alone lost less weight overall. But it took them around four years to regain what they had lost. This means that those who used GLP-1 drugs regained weight four times faster.
One reason for this could be that people who follow diet and exercise plans may build long-term habits that help them keep some of the weight off. But for those using medications, once the treatment ends, the body often goes back to how it was before.
Lead researcher Sam West said that bigger weight loss usually leads to quicker weight gain, but even when they accounted for this, people still regained weight faster after using medication. This shows the weight gain might not only be due to the amount of weight lost but also how the drug works in the body.
These drugs do help, but they are not a permanent fix. Jebb said they are a helpful tool, but obesity is a long-term condition. Just like someone with high blood pressure may need to take medicine for life, people with obesity might need to keep taking these drugs to maintain their weight loss.
However, these medications are expensive—over $1,000 a month in the U.S.—and not everyone can afford them. Some people also stop taking them because of side effects like nausea. In fact, about half of people stop using the drugs within a year.
These findings have big implications. If the medications need to be taken for life, health systems will need to think carefully about how cost-effective they are. Also, if the drugs don’t lead to lasting weight loss after stopping, then they may only be a short-term solution.
Dr. Garron Dodd, a researcher from the University of Melbourne who was not part of the study, said these medicines are just the beginning. He explained that future treatments may need to combine drugs with long-term strategies that help the brain manage hunger and energy better.
This new study helps people understand what to expect when using new weight-loss drugs. While the results during treatment can be impressive, stopping the medicine usually means the weight comes back quickly. Long-term success may require a combination of medicine, lifestyle changes, and new ways of thinking about weight and health.
If you care about weight loss, please read studies about orange that could help obesity, and a berry that can prevent cancer, diabetes and obesity.
For more health information, please see recent studies about ginger’s journey in weight management,and green tea: a cup of weight loss.
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