Ozempic and other semaglutide medications have been working wonders in terms of shedding pounds for many people, but a new study shows that they're still not as effective as surgery when it comes to weight loss – and it's not even close.
Researchers from New York University (NYU) compared sleeve gastrectomy and gastric bypass operations against semaglutide or tirzepatide. These drugs are known as glucagon-like peptide-1 (GLP-1) receptor agonists, because of the way they mimic the natural GLP-1 hormone, which controls appetite.
Using health records, the team matched people who had taken one of the weight loss drugs with people who had undergone either of the bariatric surgery operations, based on age, body mass index, and blood sugar levels.
The bottom line: people in the surgery group shed an average of 25.7 percent of their total body weight over two years, while those in the medication group lost 5.3 percent.
That's partly down to patients not sticking to their GLP-1 drugs, whereas surgery is more permanent, but the researchers also noticed smaller differences over shorter time frames – the surgery always gave the best results.
"Clinical trials show weight loss between 15 percent to 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," says Avery Brown, a surgical resident at NYU Langone Health.
"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's worth noting, however, that the study was funded by the American Society for Metabolic and Bariatric Surgery (ASMBS), who would have a vested interest in promoting surgical options.
That said, the researchers aren't outright dismissing semaglutide treatments, which also showed beneficial results in this study. With GLP-1 prescriptions doubling from 2022 to 2023, it's crucial to investigate how they compare to established surgery methods, and to figure out which options are best for each individual.
GLP-1 drugs remain much more popular than surgery, but people don't often stick to taking them. Meanwhile, only a small percentage of people eligible for surgery choose it as an option.
Weight loss isn't the only benefit that can come from Ozempic. The drug was originally approved as a way to treat type 2 diabetes, because it helps lower blood sugar levels, and studies have shown it can also reduce the risk of cancer and cardiovascular disease. In this study, bariatric surgery was associated with even better blood sugar control.
It's also important to note that surgery isn't a silver bullet either. Though safe, the procedures are invasive, permanent, and still require patients to stick to strict diet and exercise routines.
"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," says Karan Chhabra, a bariatric surgeon at the NYU Grossman School of Medicine.
The research was presented at the ASMBS annual meeting 2025.