Semaglutide (Ozempic) Outperforms Liraglutide (Saxenda) in Long-Term Weight Loss

The year 2023 marked a turning point in obesity treatment. In particular, FDA approval of the GLP-1 receptor agonist semaglutide and its introduction for weight loss increased the effectiveness of drug treatment in this field. Offering hope to people with obesity and type 2 diabetes (T2D), these new-generation medicines produced striking weight-loss results. Semaglutide achieved better outcomes than earlier treatments such as liraglutide. However, these medicines can cause side effects, albeit rarely, and doctors need to be aware of them.

In this article, we examine a new study published on September 13, 2024, in JAMA Network Open that reports notable differences in long-term weight loss between semaglutide and liraglutide, and discuss how these medicines work.

Before turning to the study's details, let us review medicines approved by the FDA (United States Food and Drug Administration) that are administered by injection for weight loss:

How Do Weight-Loss Injections Work?

GLP-1 (glucagon-like peptide-1) is a hormone naturally produced in the body. Released from the intestines after eating, it stimulates the pancreas and increases insulin secretion. Insulin helps regulate blood sugar levels. GLP-1 also slows gastric emptying, creating a feeling of fullness and suppressing appetite. In other words, it both regulates blood sugar and reduces the desire to eat.

GLP-1 receptor agonists are medicines that mimic this hormone's effects in the body. By binding to GLP-1 receptors, they increase insulin secretion, lower blood sugar and reduce the desire to eat. They also delay gastric emptying, prolonging the feeling of fullness. Through these mechanisms, people eat less and their blood sugar is better controlled.

Findings of the JAMA Study: Semaglutide Is Superior

Cleveland Clinic researchers reviewed the records of 3389 patients treated for obesity or T2D between 2015 and 2022. The study compared semaglutide and liraglutide used for obesity with the doses used to treat type 2 diabetes. The findings showed greater weight loss with semaglutide than with liraglutide. Semaglutide prescribed specifically for obesity was particularly more effective than liraglutide.

• Average weight change: Patients with diabetes lost 3.2% of their weight, compared with 5.9% among patients with obesity.
• Weight change at 1 year: Among patients with obesity, those taking semaglutide lost 5.1% of their weight, whereas those taking liraglutide lost only 2.2% (P < .001).
• The effect of continued use: Among patients taking semaglutide, 45.8% continued treatment for a year, compared with 35.6% of those taking liraglutide.

Semaglutide and Liraglutide: Weekly or Daily?

Liraglutide requires daily injections, whereas semaglutide is administered weekly by injection. This makes a substantial difference in ease of use. Semaglutide's longer action increases treatment continuation rates, while patients' expectations of drug treatment also become clearer.

An important finding was that semaglutide achieved clinically meaningful weight loss (more than 10%) in a greater proportion of patients. The research also showed that female patients lost more weight at higher doses with semaglutide than with liraglutide.

Why Is Semaglutide Preferred?

Lead author Dr. Hamlet Gasoyan emphasized that a higher proportion of semaglutide users lost weight than liraglutide users, noting that this difference is important in obesity treatment. Gasoyan stated that weight loss was more likely to be sustainable in patients treated for obesity with semaglutide in particular.

Another notable finding is that semaglutide's weight-loss effect is smaller when used to treat T2D than when used for obesity. The exact reason for this difference is not yet known, but investigating responses in these two patient groups may provide important information in the future.

Real-World Data: Why Does Semaglutide Stand Out?

Obesity specialist Dr. Michael Weintraub of NYU Langone Health notes that the study's use of real-world data helps us better understand the effectiveness of GLP-1 medicines. Dr. Weintraub says semaglutide's superiority to liraglutide is consistent with clinical trial results and offers important hope for patients.

Another major advantage of semaglutide is that, apart from insurance coverage barriers, there is no factor affecting clinical decisions. However, liraglutide's price is also expected to fall when its patent expires, making it accessible to more patients.

The Status of Weight-Loss Injections in Turkey

Most of these FDA-approved medicines used for weight loss are available in Turkey. Both Ozempic and Saxenda are available there. Weekly injections increase the likelihood that patients will continue treatment, and the results may also be more lasting.

Conclusion: Semaglutide Is Redefining Treatment Standards

Semaglutide stands out as a treatment option that produces better results than liraglutide in obesity and type 2 diabetes. Its convenient weekly injections and high rates of weight loss distinguish it from other options. But will semaglutide replace medicines requiring daily injections, such as liraglutide? This appears likely to depend on future developments in medicine costs and accessibility.