Before semaglutide and tirzepatide became household names, liraglutide was the drug that established GLP-1 receptor agonists as a viable, effective drug class, and it remains a useful reference point for understanding how far this category has developed.
What It Is
Liraglutide is a synthetic GLP-1 receptor agonist, structurally similar to semaglutide but with a shorter half-life, requiring once-daily rather than once-weekly injection. It uses a comparable fatty-acid modification strategy to extend its activity beyond natural GLP-1's few-minute half-life, just to a lesser degree than the modifications used in semaglutide.
Regulatory Status
Liraglutide is FDA-approved under the brand name Victoza for type 2 diabetes (approved 2010) and Saxenda for chronic weight management (approved 2014), making it the earlier-generation predecessor to Ozempic/Wegovy and Mounjaro/Zepbound in this drug class's development history.
What the Research Shows
Liraglutide's approval was supported by substantial Phase 3 trial programs for both diabetes and weight management, and it has the additional benefit of a longer real-world usage history than the newer once-weekly drugs, meaning more years of accumulated post-market safety data. Head-to-head and cross-trial comparisons have generally found once-weekly semaglutide and tirzepatide produce greater average weight loss than liraglutide, which is a big part of why those newer drugs have largely overtaken it in popularity and prescribing.
Common Side Effects
Liraglutide shares the same general gastrointestinal side effect profile and thyroid C-cell tumor boxed warning as semaglutide and tirzepatide, being part of the same drug class with a related mechanism, and the same contraindication for personal or family history of medullary thyroid carcinoma or MEN 2.
The Bottom Line
Liraglutide isn't the newest or most potent option in its class anymore, but it's arguably the most extensively real-world-tested, with over a decade of prescribing history since approval. For understanding the GLP-1 drug class's development, it's the direct link between early proof-of-concept and the once-weekly drugs that followed it.
Why It's Still Prescribed Today
Despite being surpassed in average efficacy by newer once-weekly drugs, liraglutide remains a relevant option in specific situations, including for patients who don't tolerate or respond well to the newer drugs, or in contexts, including some pediatric weight-management approvals, where it has a more established track record for a specific population than the newer drugs have yet accumulated. Its long real-world history also makes it a useful benchmark against which newer drugs in this class continue to be measured.