Short answer: Both are GLP-1 receptor agonists from Novo Nordisk. Semaglutide (Ozempic, Wegovy) is injected once a week; liraglutide (Victoza, Saxenda) once a day. In STEP 8, weekly semaglutide 2.4 mg produced −15.8% weight change at 68 weeks versus −6.4% on daily liraglutide 3 mg.1 Liraglutide is now available as a generic.2
| Semaglutide (Wegovy, Ozempic) | Liraglutide (Saxenda, Victoza) | |
|---|---|---|
| Mechanism | GLP-1 receptor agonist, 94% sequence homology to human GLP-13 | GLP-1 receptor agonist, 97% sequence homology to human GLP-14 |
| Approval status | FDA approved; brand only | FDA approved; generics approved (Victoza reference 2024, Saxenda reference 2025)2 |
| Label dosing schedule | Wegovy: 0.25 mg weekly, stepped up every 4 weeks to 1.7 or 2.4 mg (max 7.2 mg). Ozempic: 0.25 mg for 4 weeks, then 0.5, 1, up to 2 mg53 | Saxenda: 0.6 mg daily, up by 0.6 mg each week to 3 mg; stop if under 4% weight loss at 16 weeks. Victoza: 0.6 mg for 1 week, then 1.2 mg, max 1.8 mg64 |
| Half-life | about 7 days3 | about 13 hours6 |
| Time to peak (Tmax) | 1 to 3 days3 | 11 hours (Saxenda); 8 to 12 hours (Victoza)64 |
| Dosing frequency | Once weekly (Wegovy tablets: daily) | Once daily |
| Pen strengths | Wegovy single-dose pens 0.25 to 2.4 mg and 7.2 mg; Ozempic multi-dose pens | Multi-dose pen, 18 mg/3 mL (6 mg/mL) |
| Missed dose (label) | Ozempic: within 5 days | Skip it; if more than 3 days missed, restart at 0.6 mg6 |
| Notable label warnings | Boxed thyroid C-cell tumor warning; pancreatitis, gallbladder, kidney injury, diabetic retinopathy complications | Boxed thyroid C-cell tumor warning; pancreatitis, gallbladder, kidney injury, heart rate increase (Saxenda) |
STEP 8 randomized 338 adults with overweight or obesity and no diabetes to weekly semaglutide 2.4 mg or daily liraglutide 3 mg for 68 weeks. Average weight change was −15.8% vs −6.4%. At least 15% weight loss was reached by 55.6% vs 12.0%. Treatment was stopped for any reason by 13.5% vs 27.6%.1
SUSTAIN 10 compared Ozempic-dose semaglutide 1.0 mg weekly with liraglutide 1.2 mg daily in 577 adults with type 2 diabetes for 30 weeks. HbA1c fell 1.7% vs 1.0%, and weight 5.8 kg vs 1.9 kg.7
Half-life. Liraglutide's is about 13 hours, so it is mostly cleared within a few days and needs a daily shot. Semaglutide's is about a week, so one shot covers the week. That also changes what a missed dose means: a missed liraglutide dose is skipped, while a missed semaglutide dose can usually be taken late within the label window.