A recent single-center study found that taking GLP-1 medications such as semaglutide (commonly prescribed as Ozempic or Wegovy) before bariatric surgery did not result in greater weight loss one year after the operation.
Study overview
Investigators reviewed outcomes for 383 people who had bariatric procedures between 2022 and 2024. Ninety-two patients (about 24%) were using a GLP-1 medication before surgery, most often semaglutide. The researchers followed participants for 12 months and compared percent total body weight loss, diabetes control (A1C), postoperative complications, hospital length of stay, and emergency department visits between those who had used GLP-1s preoperatively and those who had not.
Key findings
– At 12 months after surgery there was no statistically meaningful difference in weight loss: people who had taken GLP-1s before surgery lost an average of 24% of their total body weight versus 25% in the no-GLP-1 group.
– No significant differences were seen in diabetes control, postoperative complications, hospital stay length, or ED visits between the groups.
– Those who were on GLP-1s before surgery had a higher prevalence of diabetes and higher average A1C levels, and were less likely to smoke, compared with people not taking these drugs.
– Higher preoperative BMI and male sex were associated with greater percentage weight loss. By contrast, having diabetes and undergoing a sleeve gastrectomy (versus other bariatric procedures) were linked to smaller percentage weight loss.
What the results mean and study limitations
Clinicians who reviewed the work note the findings are not necessarily surprising. Bariatric surgery tends to produce a characteristic percentage of weight loss relative to starting weight, so patients with similar preoperative BMIs often end up losing similar proportions of body weight regardless of prior medication use. The study did not reliably capture how much weight people may have already lost on GLP-1 therapy before surgery or how long they had been taking those medications, which could influence outcomes.
Other limitations include the single-center, observational design and the relatively short follow-up of 12 months. Several experts emphasize that long-term results—years after surgery—are especially relevant for obesity care because weight regain can occur over time.
Why GLP-1s may still be useful with surgery
Despite the lack of added 12-month weight-loss benefit in this analysis, specialists say GLP-1 medications can still play important roles before and after bariatric surgery. Examples include:
– Preoperative weight loss to lower surgical risk and make the operation safer for people with very high BMIs.
– Helping patients who hit a weight-loss plateau after surgery to lose additional weight.
– Treating weight regain that may occur years after a procedure as part of a long-term, individualized treatment plan.
Rather than viewing medication and surgery as mutually exclusive, many obesity experts recommend thinking of them as complementary tools for managing a chronic disease. Postoperative pharmacotherapy may be an important option for sustaining or improving outcomes over time.
Bottom line
This study indicates that, in this cohort and within a 12-month follow-up, preoperative use of GLP-1 medications did not produce greater percent total body weight loss after bariatric surgery. However, limitations in study design and follow-up mean the results do not rule out meaningful clinical benefits of GLP-1s used before or after surgery, particularly for reducing perioperative risk, addressing plateaus, and treating long-term weight regain. Patients considering bariatric surgery should discuss the timing and role of GLP-1 therapy with their bariatric and obesity-care teams to tailor a plan to their individual needs and goals.
