A 31-amino-acid GLP-1 analog with 97% homology to native GLP-1. The first long-acting GLP-1 receptor agonist, enabling once-daily dosing. FDA-approved as Victoza (diabetes) and Saxenda (obesity). Paved the way for semaglutide.
Liraglutide is a 31-amino-acid GLP-1 analog that was the first long-acting incretin mimetic to reach the market. Developed by Novo Nordisk and approved in 2010, it demonstrated that GLP-1 receptor agonism could be a viable therapeutic strategy for both Type 2 diabetes and obesity.
Liraglutide has 97% sequence homology to native GLP-1 (one amino acid change: Lys34→Arg34) plus a C16 fatty acid (palmitic acid) attached to Lys26 via a glutamic acid spacer. This fatty acid enables albumin binding, extending the half-life from 2 minutes (native GLP-1) to approximately 13 hours — enabling once-daily injection.
Liraglutide's mechanism is identical to native GLP-1 and semaglutide — it binds and activates the GLP-1 receptor, a Gs-coupled GPCR. The clinical differences between liraglutide and semaglutide are pharmacokinetic, not pharmacodynamic: liraglutide's C16 fatty acid provides sufficient albumin binding for once-daily dosing, while semaglutide's C18 fatty diacid provides stronger albumin affinity for once-weekly dosing.
| Pathway | Effect | Significance |
|---|---|---|
| Insulin secretion | Glucose-dependent β-cell stimulation | Lowers blood sugar only when glucose is elevated — low hypoglycemia risk |
| Glucagon suppression | Reduces α-cell glucagon output | Prevents excessive hepatic glucose production |
| Gastric emptying | Slows food transit from stomach | Reduces postprandial glucose spikes and increases satiety |
| Appetite suppression | CNS GLP-1R activation in hypothalamus | Average 8% weight loss (Saxenda 3.0 mg dose) |
| Cardioprotection | Reduces atherosclerosis and inflammation | 13% reduction in MACE in LEADER trial |
| Study | Design | Findings | Level |
|---|---|---|---|
| LEAD program | Phase III, T2D, multiple trials | Superior HbA1c reduction vs sulfonylureas and comparable to insulin; significant weight loss | Level I |
| SCALE program | Phase III, obesity, n=3,731 | 8% mean weight loss at 3.0 mg dose over 56 weeks (Saxenda) | Level I |
| LEADER trial | Phase III, CV outcomes, n=9,340 | 13% reduction in major adverse cardiovascular events (MACE) vs placebo | Level I |
| Pediatric obesity | Phase III | Approved for adolescents (12-17) with obesity. Significant BMI reduction vs placebo. | Level I |
GI side effects: Nausea (39%), diarrhea, vomiting — similar profile to all GLP-1 agonists. Dose titration helps.
Thyroid warning: Same boxed warning as semaglutide for thyroid C-cell tumors in rodents. Contraindicated with MTC/MEN2 history.
Pancreatitis: Rare acute pancreatitis cases reported. Same monitoring as semaglutide.
Injection frequency: Daily injection is less convenient than weekly semaglutide — a major reason for semaglutide's market dominance.
| Jurisdiction | Status |
|---|---|
| FDA | Approved: Victoza (T2D, 2010), Saxenda (obesity, 2014) |
| EMA | Approved for T2D and weight management |
| Historical | First long-acting GLP-1 agonist. Proof-of-concept for the entire class. |
| Feature | Liraglutide | Semaglutide |
|---|---|---|
| Half-life | ~13 hours (daily injection) | ~7 days (weekly injection) |
| Weight loss | ~8% (SCALE trials) | ~15-17% (STEP trials) |
| Fatty acid | C16 palmitic acid | C18 fatty diacid |
| DPP-4 resistance | Lys34→Arg34 only | Ala8→Aib (steric shield) |
| Dosing | Once daily | Once weekly |
| Market position | First-to-market GLP-1 | Market leader |