New research from UCL supports the use of the weight loss drug semaglutide in patients who do not receive sufficient benefit from bariatric surgery.
Metabolic/bariatric surgery is a highly effective treatment for people with severe obesity and metabolic health conditions, and it works by changing the anatomy of the digestive system, thereby altering its function and the hormones it produces. Surgery includes sleeve gastrectomy and gastric bypass.
However, about one in five people who undergo bariatric surgery do not lose enough weight or gain it back afterwards. Approximately 500,000 bariatric surgeries are performed worldwide each year, and there is a significant need for alternative treatments for this group.
Previously, the options for patients who did not respond optimally to bariatric surgery were lifestyle interventions (with limited efficacy) or additional surgery (which increased surgical risks, was invasive, and was only available to a minority of patients).
Published in natural medicineThe BARI-STEP trial, led by Dr Janine Macaronidis from the UCL Obesity Research Centre, investigated the use of semaglutide 2.4mg in patients who had not responded well to bariatric surgery.
A similar drug, liraglutide, has previously shown some efficacy in this group, but previous studies found that semaglutide produced greater weight loss. BARI-STEP is the first randomized controlled trial of semaglutide in patients after bariatric surgery.
The study involved 70 patients recruited from University College London Hospital and Homerton University Hospital. Participants participated for 68 weeks and were randomly assigned to receive either semaglutide injections or a placebo injection. Both groups also received lifestyle advice and support with a low-calorie diet.
For 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 weight, compared with 3% in the placebo group.
Researchers found that most of the weight loss came from body fat, not muscle.
The semaglutide group also showed improvements in blood sugar levels, cholesterol, and other measures related to heart and metabolic health. Patients also reported improved quality of life.
The side effects seen in this study were already well known from previous studies of semaglutide, including nausea and decreased appetite.
These findings strengthen the rationale for using semaglutide in people who do not respond well to bariatric surgery and provide an alternative to revision surgery. They also suggest that combining surgery and weight loss drugs is an important approach to treating severe obesity.
As a next step, larger, longer-term studies with more diverse patient groups are needed. We also want to investigate whether semaglutide can help patients before and after surgery. ”
Dr Janine Macaronidis, UCL Obesity Research Center
This research was supported and co-funded by the NIHR University College London Hospital Biomedical Research Center.
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university college london
Reference magazines:
Stanley, C. Others. (2026). Comparison of semaglutide versus placebo in individuals with inadequate weight loss after bariatric surgery: A double-blind, randomized, placebo-controlled trial. natural medicine. DOI: 10.1038/s41591-026-04416-4. https://www.nature.com/articles/s41591-026-04416-4
