Ozempic and Weight-Loss Surgery: Which Delivers Better Results?

Ozempic and other semaglutide medicines have helped many people lose substantial amounts of weight. However, a recent study indicates that they may not always be the most effective medical treatment for weight loss.

Indeed, the evidence suggests there is a considerable gap between these drugs and another type of medical intervention.

Ozempic, GLP-1 medicines and bariatric surgery compared

In a 2025 study, New York University (NYU) researchers compared weight-loss surgery - sleeve gastrectomy and gastric bypass procedures - with semaglutide or tirzepatide.

These medicines are called glucagon-like peptide-1 (GLP-1) receptor agonists because they replicate the effects of the naturally occurring GLP-1 hormone, which regulates appetite.

Drawing on health records, the researchers matched people taking one of the weight-loss medicines with people who had received either bariatric procedure, taking account of age, body mass index and blood sugar levels.

After two years, participants in the surgery group had lost an average of 25.7 percent of their overall body weight, compared with 5.3 percent among those receiving medication.

Why surgery produced greater weight loss

Part of the difference was linked to patients not continuing with their GLP-1 medicines, while surgery has a more lasting effect. Yet the researchers also found smaller disparities over shorter periods: surgery consistently delivered the strongest outcomes.

"Clinical trials show weight loss between 15 percent and 21 percent for GLP-1s, but this study suggests that weight loss in the real world is considerably lower even for patients who have active prescriptions for an entire year," said NYU surgical resident Avery Brown when the results were presented in June 2025.

"We know as many as 70 percent of patients may discontinue treatment within one year. GLP-1 patients may need to adjust their expectations, adhere more closely to treatment or opt for metabolic and bariatric surgery to achieve desired results."

It is worth bearing in mind that the American Society for Metabolic and Bariatric Surgery (ASMBS) funded the study, giving it an interest in supporting surgical approaches.

The researchers did not dismiss semaglutide treatments outright, as the medicines also produced positive results in the study.

As GLP-1 prescriptions have risen sharply in recent years, it is important to assess how they measure up against established surgical treatments and establish which option is most suitable for each person.

"While both patient groups lose weight, metabolic and bariatric surgery is much more effective and durable," said ASMBS President Ann M. Rogers, who was not involved in the study.

Although GLP-1 medicines remain far more popular than surgery, patients often do not continue taking them. At the same time, only a small proportion of people who qualify for surgery select it.

Ozempic benefits, blood sugar control and surgery risks

Weight loss is not the sole potential benefit of Ozempic.

The medicine was initially approved for treating type 2 diabetes because it helps to reduce blood sugar levels. Studies have also indicated that it may lower the risk of cancer and cardiovascular disease.

In this research, however, bariatric surgery was linked with even stronger blood sugar control.

Surgery is not a complete solution either. While the procedures are safe, they are invasive and permanent, and patients must still follow strict diet and exercise regimens.

"In future studies we will aim to identify what healthcare providers can do to optimize GLP-1 outcomes, identify which patients are better treated with bariatric surgery versus GLP-1s, and determine the role out-of-pocket costs play in treatment success," said Karan Chhabra, a bariatric surgeon at the NYU Grossman School of Medicine.

The research was presented at the 2025 ASMBS annual meeting.

An earlier version of this article was published in June 2025.