Semaglutide vs Liraglutide: Older and Newer GLP-1 Options

Semaglutide and liraglutide are both GLP-1 receptor agonists, and both were developed by Novo Nordisk, but they aren't interchangeable. They differ in molecular structure, how long they last in the body, how often they're taken, which brands they're sold under, what they're approved for and what the trials showed.

Brands and routines at a glance (US)

• Liraglutide is a once-daily injection. Victoza is approved for type 2 diabetes (including reducing major cardiovascular events in adults with type 2 diabetes and established heart disease), and Saxenda is a higher-dose version approved for chronic weight management in adults and in adolescents aged 12 and older who meet weight criteria. Generic liraglutide is also available in the US: the FDA approved the first generic referencing Victoza in December 2024, and the first generic version of Saxenda launched in August 2025.
• Semaglutide lasts longer, so it can be taken once weekly by injection: Ozempic for type 2 diabetes and related heart and kidney indications, and Wegovy for weight management and other labeled uses. It also comes as daily tablets (Rybelsus and Ozempic tablets for type 2 diabetes, Wegovy tablets for weight). There's more on that in GLP-1 pills vs injections.

The same ingredient can carry different labels depending on the brand and dose, so the exact product name on your prescription matters.

Is there a head-to-head trial?

Yes, which is unusual and useful. The STEP 8 trial (published in JAMA in 2022) randomized 338 adults with overweight or obesity without diabetes to weekly semaglutide 2.4 mg or daily liraglutide 3.0 mg (the weight-management doses), or placebo, for 68 weeks, alongside diet and activity counseling. Average weight change was:

• −15.8% with semaglutide
• −6.4% with liraglutide
• −1.9% with placebo

More people stopped treatment for any reason on liraglutide (27.6%) than on semaglutide (13.5%), while gastrointestinal side effects were similarly common in both groups (84.1% and 82.7%). The comparison between the two medicines wasn't blinded, and results apply to this population and these doses. People with type 2 diabetes, or on diabetes doses, may see different results.

Side effects and risks

Nausea, diarrhea, vomiting and constipation are common across the class, especially as doses increase. Both medicines share important class warnings, but specific rates, warnings and approved benefits come from each product's own label. A benefit shown for one medicine, such as a heart or kidney outcome, shouldn't be assumed for another just because both act on the same receptor. Our guide to Ozempic side effects covers what's common and what's serious.

Questions for your prescriber

Why is one being suggested over the other for me? Which outcome matters most in my case: blood sugar, weight, heart or kidney health? Does a daily or weekly routine fit better? What do coverage and cost look like, including generics? Which side effects should prompt a call? And please don't switch, combine or adjust these medicines on your own, because doses don't convert directly between them.

There's no single "best GLP-1" for everyone. The useful comparison is product-specific, weighing evidence, approved uses, safety, routine and your own health context together.