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Why Taking GLP-1s Like Ozempic Before Bariatric Surgery May Not Lead to More Weight Loss
New research shows that using a GLP-1 before bariatric surgery may not increase weight loss. coldsnowstorm · E+/Getty
A new study found that using GLP-1 medications, such as Ozempic or Wegovy, before bariatric surgery was not associated with greater weight loss 12 months after the procedure.
Researchers also found no significant differences in diabetes control, postoperative complications, length of hospital stay, or emergency department visits.
Experts say GLP-1 medications may still provide benefits before or after bariatric surgery, including helping with weight loss before surgery or managing weight regain afterward.
A new study suggests that using GLP-1 medications, such as Ozempic and Wegovy, before bariatric surgery may not lead to greater weight loss after the procedure.
The research, published August 12 in JAMA Surgery, also found no significant differences in diabetes control, postoperative complications, length of hospital stay, or emergency department visits between people who used GLP-1s before surgery and those who did not.
However, the findings don’t rule out potential benefits of using GLP-1 medications before or after bariatric surgery, including helping some people lose weight before the procedure or manage weight regain afterward.
GLP-1 use before bariatric surgery did not increase weight loss
Researchers analyzed data from 383 people who underwent bariatric surgery at a single center between 2022 and 2024. Of those, 92 (24%) were using a GLP-1 medication, primarily semaglutide (Ozempic, Wegovy), before surgery.
The researchers tracked participants for 12 months after surgery, including total body weight loss percentage, complications, and postoperative hemoglobin A1C levels.
The individuals using a GLP-1 medication before surgery were similar in age, body mass index (BMI), sex, and other characteristics to those who weren’t using the medications. However, the GLP-1 group had a higher prevalence of diabetes and a higher average A1C level. This group also had a lower prevalence of smoking.
At 12 months, the difference in weight loss was not statistically significant. People who had used GLP-1 medications before surgery had lost an average of 24% of their total body weight, compared with 25% among those who had not used the medications.
A greater percentage of total body weight loss was observed among people with a higher BMI before surgery and among males.
Meanwhile, diabetes and having a type of bariatric surgery called a sleeve gastrectomy were associated with a lower percentage of weight loss.
What to know about the study’s findings and limitations
Mir Ali, MD, a bariatric surgeon, bariatric medicine specialist, and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, noted that the study’s findings were not surprising.
“Because people tend to lose a certain percentage of their starting weight after bariatric surgery, it makes sense that patients who begin at a similar BMI would be expected to lose a similar amount of weight. So, in that context, the study’s findings are not particularly surprising,” he told Healthline.
Ali, who was not involved in the research, also noted that the study did not specifically account for weight loss that participants may have already achieved from GLP-1 medications before surgery.
“In my practice, I’ve found that losing weight before surgery can be beneficial not only for reducing some of the risks associated with surgery, but also for supporting better long-term weight-loss outcomes,” he said.
The researchers similarly noted that they were unable to accurately quantify how much weight participants lost before surgery or how long they had been taking GLP-1 medications.
Paunel Vukasinov, MD, dual board certified internist and obesity medicine specialist, with Medical Offices of Manhattan, who wasn’t involved in the study, noted that the study only goes out 12 months.
“For obesity, I am much more interested in what happens years after the surgery as the risk of weight regain increases,” he said.
Why GLP-1s may provide additional benefits alongside bariatric surgery
Although the study found no significant difference in weight loss between people who used GLP-1 medications before bariatric surgery and those who did not, experts say the medications may still be useful before and after surgery.
“I would reconsider ‘medication versus surgery’ and instead think about obesity as a chronic disease for which we have several complementary therapeutic tools,” said Vukasinov.
He added that postoperative pharmacotherapy may ultimately be very important because bariatric surgery should not necessarily be viewed as the final treatment a patient ever receives.
Ali told Healthline that in his practice, he uses GLP-1 medications in several different situations. For example, for those who are starting out with a very high BMI, using a GLP-1 medication can help them lose weight, potentially reduce surgical risks, and improve their chances of reaching a healthier weight.
He noted that he will also offer GLP-1 medications to individuals who reach a weight loss plateau following surgery and would like to lose more weight.
“They can also be helpful for patients who experience weight regain several years after their procedure. In these situations, GLP-1 medications can be one tool we consider as part of a broader, individualized weight-management plan,” he said.
