People may regain weight within weeks after stopping weight loss drugs, study finds

People taking weight loss drugs such as Ozempic and Wegovy may begin to regain weight within weeks of stopping the medication, a new study has found.

Published in the journal BMC Medicine, the research reviewed data from 11 previous clinical trials involving nearly 2,500 participants. It revealed a consistent trend of weight regain following the discontinuation of anti-obesity medications.

At least six drugs have been approved to treat obesity in adults - orlistat, naltrexone-bupropion, semaglutide, liraglutide, tirzepatide and phentermine-topiramate. Of the 11 trials assessed in the review, six focused specifically on semaglutide, the active ingredient in Ozempic and Wegovy.

While previous research has shown that these medications can help people achieve significant weight loss, the latest review suggests the benefits may diminish once treatment ends. According to the findings, weight regain can begin as early as eight weeks after discontinuation and may continue for up to 20 weeks before stabilising.

“The long-term change of weight after discontinuation of AOMs is still lacking systematic evaluation,” the researchers noted.

Semaglutide, initially developed for managing type 2 diabetes and obesity, has more recently gained popularity as a rapid weight loss solution. However, the study, led by researchers including those from Peking University People’s Hospital in China, found that a rebound in weight can occur shortly after people stop taking the drug.

The review analysed data from 1,574 individuals in treatment groups and 893 in control groups. Researchers tracked body weight and BMI post-treatment, adjusting for variables such as the type of medication used, the presence of diabetes and adherence to lifestyle changes such as diet and exercise.

“Significant weight regain occurred eight weeks after discontinuation of AOMs and was sustained through 20 weeks,” the study found.

Weight gain at eight, 12 and 20 weeks post-treatment was statistically significant. The degree of rebound appeared to vary depending on the drug and whether individuals maintained supportive lifestyle habits.

In one case cited, those who completed a 36-week course of tirzepatide regained nearly half the weight they had previously lost when switched to a placebo.

The authors of the study are calling for further research with longer follow-up periods to better understand the factors that influence weight changes after treatment is stopped.