Head-to-head comparison
| Property | Semaglutide | Liraglutide |
|---|---|---|
| Category | Weight Loss | Weight Loss |
| Legal Status | Prescription | Prescription |
| Primary Route | subcutaneous | subcutaneous |
| Half-life | ~7 days | ~13 hours |
| Mol. Weight | 4,113.58 Da | 3,751.2 Da |
| Side Effects | Nausea (39%), Vomiting, Diarrhea | Nausea (39%), Diarrhea, Constipation |
Key differences
- Dosing frequency: Semaglutide is dosed once weekly; liraglutide is dosed once daily. This is the most significant practical difference.
- Weight loss efficacy: Semaglutide (2.4 mg weekly) produces 15–17% weight loss; liraglutide (3.0 mg daily) produces approximately 8% weight loss in clinical trials.
- Half-life: Semaglutide has a half-life of approximately 7 days; liraglutide has a half-life of approximately 13 hours.
- Molecular modification: Semaglutide has a C-18 fatty acid acylation that promotes albumin binding and extends half-life; liraglutide has a C-16 fatty acid acylation with shorter duration.
- Brand names: Semaglutide is sold as Ozempic (diabetes), Wegovy (obesity), and Rybelsus (oral); liraglutide is sold as Victoza (diabetes) and Saxenda (obesity).
- Oral formulation: Semaglutide has an FDA-approved oral form (Rybelsus); liraglutide is injectable only.
- Market generation: Liraglutide was FDA-approved in 2010 (diabetes) and 2014 (obesity); semaglutide was approved in 2017 (diabetes) and 2021 (obesity). Semaglutide is considered the next-generation product.
The verdict
Semaglutide is generally considered the superior GLP-1 agonist based on clinical data: it produces roughly double the weight loss of liraglutide while requiring only weekly rather than daily injection. However, liraglutide has a longer safety track record, may be preferred when a shorter-acting agent is desired, and remains a viable option when semaglutide is unavailable or not covered by insurance. Both are FDA-approved prescription medications.
Frequently asked questions
Clinical trial data shows semaglutide produces approximately 15–17% body weight loss compared to about 8% with liraglutide. The STEP trials (semaglutide) and SCALE trials (liraglutide) were not head-to-head, but the difference is substantial and consistent across indirect comparisons.
Semaglutide has a C-18 fatty acid modification (vs C-16 in liraglutide) that promotes stronger albumin binding, extending its half-life to approximately 7 days. Liraglutide's half-life is only about 13 hours, requiring daily injection to maintain therapeutic levels.
Switching should be done under physician guidance. The typical approach is to stop liraglutide and begin semaglutide at the starting dose (0.25 mg weekly), then titrate up following the standard schedule. There is no direct dose conversion between the two.
List prices are broadly similar for both branded products. Insurance coverage and formulary placement vary. In some markets, liraglutide (Saxenda) may have better coverage due to its longer market presence. Compounded versions of both have existed but face regulatory restrictions.
Yes, semaglutide is available as Rybelsus in oral tablet form, making it the first and currently only oral GLP-1 receptor agonist. Liraglutide is available only as an injectable. The oral form of semaglutide has somewhat lower bioavailability than the injectable form.