Semaglutide vs Liraglutide: Which Is Right for You?
Both are FDA-approved GLP-1 receptor agonists from Novo Nordisk. Semaglutide is injected once weekly; liraglutide once daily. In the head-to-head STEP 8 trial, semaglutide 2.4 mg weekly produced −15.8% mean weight change at 68 weeks versus −6.4% with liraglutide 3.0 mg daily.
Side-by-side comparison
| Semaglutide | Liraglutide | |
|---|---|---|
| Class | GLP-1 receptor agonist | GLP-1 receptor agonist |
| Dosing frequency | Once weekly (injection) or daily tablet | Once daily (injection) |
| Weight-management brand | Wegovy | Saxenda |
| Diabetes brand | Ozempic, Rybelsus | Victoza |
| Head-to-head (STEP 8) | −15.8% at 68 wk (2.4 mg weekly) | −6.4% at 68 wk (3.0 mg daily) |
| FDA status | Approved | Approved |
Complete comparison (2026)
Key takeaways
- STEP 8 is a direct randomized comparison, so these numbers are head-to-head rather than cross-trial.
- Both carry the GLP-1-class boxed warning for thyroid C-cell tumors.
- Semaglutide's long half-life (about a week) allows weekly dosing; liraglutide's (about 13 hours) requires daily dosing.
What are Semaglutide and Liraglutide?
Semaglutide is a long-acting GLP-1 receptor agonist peptide, made by Novo Nordisk, that is FDA-approved for type 2 diabetes (Ozempic, Rybelsus) and for chronic weight management (Wegovy).
Liraglutide is a once-daily GLP-1 receptor agonist, FDA-approved as Victoza and Saxenda; generic versions are available.
Mechanism differences
Both mimic the gut hormone GLP-1, slowing gastric emptying, increasing glucose-dependent insulin release and reducing appetite. Semaglutide was engineered for albumin binding and a half-life of about one week; liraglutide binds albumin less strongly and has a half-life of about 13 hours.
Effectiveness
In STEP 8 (JAMA, 2022), adults with overweight or obesity lost a mean 15.8% of body weight on semaglutide 2.4 mg weekly versus 6.4% on liraglutide 3.0 mg daily over 68 weeks. In its own pivotal trial (SCALE, NEJM 2015), liraglutide 3.0 mg produced 8.0% versus 2.6% with placebo at 56 weeks.
Side effect profiles
Both are dominated by gastrointestinal effects: nausea, diarrhea, vomiting and constipation. In STEP 8 the proportion stopping treatment for adverse events was similar between groups. Labels for both warn about pancreatitis, gallbladder disease and thyroid C-cell tumors.
Dosing & administration
Wegovy escalates from 0.25 mg weekly to 2.4 mg over 16 weeks (label). Saxenda escalates from 0.6 mg daily by 0.6 mg each week to 3.0 mg daily (label). See the labels for full tables.
Cost
Liraglutide is available as a generic (Victoza's generic launched in 2024); semaglutide is brand-only. Prices change frequently and depend on coverage, so we don't quote them.
FDA & regulatory status
Both FDA-approved. Compounded versions are not FDA-approved products.
Who should choose which
The choice is a clinical decision made with a prescriber, considering health history, tolerability, injection frequency, coverage and supply.
What the evidence does not show
- That either drug keeps weight off after stopping.
- Long-term outcomes of switching between the two.
Frequently asked questions
Is semaglutide better than liraglutide for weight loss?
In the head-to-head STEP 8 trial, semaglutide 2.4 mg weekly produced more weight loss (−15.8%) than liraglutide 3.0 mg daily (−6.4%) over 68 weeks.
Can you switch from liraglutide to semaglutide?
Switching is a prescriber decision; labels give no direct conversion between the two because they are dosed on different schedules.
Are both made by the same company?
Yes. Novo Nordisk developed both.
References
- Effect of weekly subcutaneous semaglutide vs daily liraglutide on body weight in adults with overweight or obesity without diabetes: the STEP 8 randomized clinical trial
- A randomized, controlled trial of 3.0 mg of liraglutide in weight management
- Once-Weekly Semaglutide in Adults with Overweight or Obesity
- WEGOVY (semaglutide) prescribing information
- FDA Approves Fourth Product Under National Priority Voucher Program, Higher Dose Semaglutide
- Semaglutide — PubChem compound summary (CID 56843331)
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