Weight loss drug semaglutide helps patients who do not respond to bariatric surgery, research finds
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Metabolic/bariatric surgery is a highly effective treatment for people living with severe obesity and/or metabolic health conditions, which works through changing the anatomy of the digestive system and thereby changing the way it functions and the hormones it produces. Procedures include the sleeve gastrectomy and gastric bypass.
However, around one in five people who have bariatric surgery either do not lose enough weight or regain weight afterward. With around 500,000 bariatric surgeries taking place around the world each year, there is a large need for alternative treatments for this group.
Previously, options for patients who responded sub-optimally to bariatric surgery were lifestyle intervention—which had limited benefit—or further surgery—which had increased surgical risk, was invasive, and was only available to a minority of patients.
Published in Nature Medicine, the BARI-STEP trial, led by Dr. Janine Makaronidis at the UCL Center for Obesity Research, looked at the use of semaglutide at a dose of 2.4mg in patients who had not responded well to bariatric surgery.
A similar medicine, liraglutide, has previously shown some benefit in this group, but earlier research found semaglutide produced greater weight loss. BARI-STEP is the first randomized controlled trial of semaglutide in patients following bariatric surgery.
The study involved 70 patients recruited from University College London Hospitals and Homerton University Hospital. Participants took part for 68 weeks and were randomly assigned to receive either semaglutide or a placebo injection. Both groups also received lifestyle advice and support with a reduced-calorie diet.
Among patients taking semaglutide:
- 85% lost at least 10% of their body weight, compared with 7% in the placebo group
- 62% lost at least 15% of their body weight, compared with 7% in the placebo group
- 47% lost at least 20% of their body weight, compared with 3% in the placebo group
Researchers found that most of the weight loss came from body fat rather than muscle.
The semaglutide group also showed improvements in blood sugar levels, cholesterol, and other measures linked to heart and metabolic health. Patients also reported better quality of life.
The side effects seen in the study were already well known from previous semaglutide research, including nausea and reduced appetite.
Dr. Makaronidis said, "These findings strengthen the case for using semaglutide in people who do not respond well to bariatric surgery, offering an alternative to repeat operations. They also suggest that combining surgery with weight-loss medicines is an important approach to treating severe obesity.
"As next steps, we need larger and longer studies involving more diverse groups of patients. We would also like to investigate whether semaglutide could help patients before surgery as well as afterwards."
Publication details
Semaglutide vs placebo in individuals with poor weight-loss following bariatric surgery: a double-blinded, randomised, placebo-controlled trial, Nature Medicine (2026). DOI: 10.1038/s41591-026-04416-4
Journal information: Nature Medicine
Key medical concepts
SemaglutideWeight Loss SurgeryObesity, Morbidblood sugar levelLiraglutide
Clinical categories
EndocrinologyWeight managementGeneral surgeryClinical pharmacology Provided by University College London Who's behind this story?
Sadie Harley
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