Liraglutide

Liraglutide is a GLP-1 receptor agonist developed by Novo Nordisk with 97% amino acid homology to human GLP-1. It features a C16 palmitic acid fatty acid chain attached via a glutamic acid spacer at lysine-26, enabling albumin binding that extends its half-life to 13 hours — allowing once-daily dosing. Approved as Victoza (2010) for type 2 diabetes and Saxenda (2014) for chronic weight management, liraglutide was the first long-acting GLP-1RA and paved the way for semaglutide and tirzepatide. Clinical trials demonstrated HbA1c reductions of 1.1-1.5% and weight loss of 5-8% for the diabetes indication, with the LEADER trial establishing 13% cardiovascular risk reduction. For obesity, the SCALE program showed 8% body weight reduction at the 3.0 mg dose.

GLP-1 Receptor Agonism Liraglutide activates the GLP-1 receptor on pancreatic beta cells, stimulating glucose-dependent insulin secretion through cAMP/PKA and Epac2 signaling. It simultaneously suppresses glucagon from alpha cells. Central GLP-1R activation in the hypothalamus suppresses appetite through POMC neuron activation and NPY/AgRP inhibition. Delayed gastric emptying contributes to postprandial satiety. The palmitic acid sidechain enables non-covalent albumin binding (~99% bound), protecting against DPP-4 degradation and renal clearance while maintaining a slow-release depot effect from the injection site.

Type 2 Diabetes (Victoza) FDA-approved for glycemic control. LEADER trial demonstrated 13% MACE reduction and cardiovascular benefit. Obesity (Saxenda) FDA-approved at 3.0 mg/day for chronic weight management. SCALE trials showed 8% body weight loss with improvements in metabolic parameters. MASH/NASH The LEAN trial demonstrated histological resolution of NASH in 39% of patients vs 9% placebo. Cardiovascular Protection LEADER trial established cardiovascular safety and modest benefit, leading to expanded indications.

cAMP/PKA/CREB beta cell signaling drives insulin gene transcription and glucose-stimulated insulin secretion. PI3K/Akt pathway promotes beta cell survival. Central melanocortin system activation mediates appetite suppression. GH/IGF-1 independent lipolytic pathways contribute to weight loss.

Nausea (20-40%), vomiting, diarrhea, and constipation are the most common GI side effects, typically diminishing over 4-8 weeks. Injection site reactions occur in 2%. Pancreatitis risk is rare (<0.5%). Thyroid C-cell tumor boxed warning based on rodent data. Gallbladder events associated with rapid weight loss. Hypoglycemia risk increases with concurrent sulfonylurea or insulin use.

Liraglutide pens (Victoza, Saxenda) should be stored at 2-8°C before first use. After first use, store at room temperature (up to 30°C) or refrigerated for up to 30 days. Protect from light. Do not freeze.

FDA-approved as Victoza (2010, type 2 diabetes) and Saxenda (2014, weight management). EMA and worldwide approvals. WADA-prohibited under S2 category.