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Liraglutide vs semaglutide: what the head-to-head trial shows
Both are FDA-approved GLP-1 medicines for weight management. In STEP 8, the trial that put them directly against each other, once-weekly semaglutide 2.4 mg produced more average weight loss than once-daily liraglutide 3.0 mg at 68 weeks: 15.8% against 6.4%.
Evidence grade A: what kinds of studies support the claims on this page, with limits. It is not a verdict on any product. How we grade
On this page
In brief
Should you care? Yes, if you are comparing the two, or have been told they are interchangeable. They are different medicines with different dosing schedules, and one direct trial puts a number on the difference in average weight loss.The short version
- Head-to-head result: at 68 weeks, average weight change was -15.8% with semaglutide and -6.4% with liraglutide, a difference of 9.4 percentage points.1
- Schedule: liraglutide for weight management (Saxenda) is a daily injection; semaglutide for weight management (Wegovy injection) is weekly.23
- Same boxed warning: both labels warn about thyroid C-cell tumors seen in rodents.23
Side by side
Liraglutide and semaglutide are both GLP-1 receptor agonists: medicines that copy a gut hormone called glucagon-like peptide-1. Each is sold under more than one brand name for different purposes. The table lists only what the current US labels say.
| Liraglutide (Saxenda) | Semaglutide (Wegovy injection) | |
|---|---|---|
| How often it is given | Once daily2 | Once weekly3 |
| Weight-management indication | With a reduced-calorie diet and more physical activity: adults and children 12 and older with obesity (body weight above 60 kg for the pediatric group), and adults with overweight plus at least one weight-related condition2 | With a reduced-calorie diet and more physical activity: adults and children 12 and older with obesity, and adults with overweight plus at least one weight-related condition3 |
| Other labelled uses of the same brand | None listed on the Saxenda label; liraglutide for type 2 diabetes is a separate brand, Victoza24 | Lowering the risk of major cardiovascular events in adults with established cardiovascular disease and obesity or overweight; noncirrhotic MASH (a liver condition; approved under accelerated approval); semaglutide for type 2 diabetes is a separate brand, Ozempic35 |
| Boxed warning | Risk of thyroid C-cell tumors (seen in rodents; the label says it is unknown whether it happens in humans)2 | Same warning, worded for semaglutide3 |
| Contraindicated with | A personal or family history of medullary thyroid carcinoma, or Multiple Endocrine Neoplasia syndrome type 2; serious hypersensitivity to liraglutide2 | A personal or family history of medullary thyroid carcinoma, or Multiple Endocrine Neoplasia syndrome type 2; a prior serious hypersensitivity reaction to semaglutide or any excipient3 |
| Medication Guide revised | February 20262 | June 20263 |
The Wegovy label now also covers a once-daily tablet. This page is about the injection, because the trial below tested injections only.13 For each medicine on its own, see liraglutide and semaglutide.
What STEP 8 tested and found
STEP 8 was a randomized, 68-week, phase 3b trial at 19 US sites. It enrolled 338 adults with a body mass index of 30 or more, or 27 or more with at least one weight-related condition, and without diabetes. Everyone also received diet and physical-activity counseling. Participants were assigned to weekly semaglutide 2.4 mg, daily liraglutide 3.0 mg, or matching placebo for each.1
| Measure | Semaglutide 2.4 mg weekly (126 people) | Liraglutide 3.0 mg daily (127 people) |
|---|---|---|
| Average change in body weight | -15.8% | -6.4% |
| Lost 10% or more of body weight | 70.9% | 25.6% |
| Lost 15% or more | 55.6% | 12.0% |
| Lost 20% or more | 38.5% | 6.0% |
| Stopped treatment for any reason | 13.5% | 27.6% |
| Had a gastrointestinal side effect | 84.1% | 82.7% |
The difference in average weight change was 9.4 percentage points (95% confidence interval -12.0 to -6.8). Pooled placebo groups lost 1.9% on average.1 Stomach and bowel side effects were about equally common on both medicines, so the larger weight loss did not come with a visibly higher rate of them in this trial.
What the result does and does not tell you
- It is an average. A trial average cannot say what any one person will experience.
- It is one trial. It was 68 weeks long, enrolled adults without diabetes, and ran at US sites.1
- The comparison between the two drugs was open-label. The trial report describes the semaglutide-versus-liraglutide comparison as open-label, with each active drug double-blinded only against its own matching placebo.1
- The trial ties to the manufacturer. Novo Nordisk makes both brand-name products, and the authors list Novo Nordisk employment and grants in their disclosures.123
- It does not test other forms. It did not test Victoza or Ozempic for diabetes, the Wegovy tablet, or doses other than those above.
- Side-effect rates on the two labels are not comparable. Each label reports numbers from its own trials, run at different times in different people, so this page does not set them side by side. The head-to-head figure for stomach and bowel effects is in the table above.
Which medicine, if either, suits a particular person is a decision for that person and a prescriber. Cost, insurance coverage, other conditions and tolerability all matter and are outside what this page can assess.
Same drug name, different product
The approved products above are the ones FDA reviewed. Liraglutide and semaglutide are also advertised in other forms. FDA says unapproved versions of GLP-1 medicines “do not undergo FDA’s review for safety, effectiveness and quality before they are marketed,” and that compounded drugs are not FDA-approved.67 A vial with a “research use only” label is not an approved medicine either. These pages explain the differences without endorsing any product:
- Generic liraglutide vs compounded liraglutide
- What “Research Use Only” actually means
- Are peptides legal?
As of this review
As of 1 October 2026
This page uses the STEP 8 publication (JAMA, 2022) and the current Saxenda, Wegovy, Victoza and Ozempic labels on DailyMed, revised as shown in the references. We will revise and date this page if a label changes the indications or warnings above, or if a new head-to-head trial is published. To report an error, use the “Report an error” topic on About.
What you can do next
References
- Rubino DM, Greenway FL, Khalid U, et al. “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.” JAMA 2022;327(2):138-150. DOI 10.1001/jama.2021.23619, PMID 35015037, ClinicalTrials.gov NCT04074161. Abstract and author disclosures read in the PubMed record. PubMed
- Saxenda (liraglutide) injection, prescribing information (Medication Guide revised 02/2026; Instructions for Use revised 06/2026). National Library of Medicine DailyMed. DailyMed
- Wegovy (semaglutide) injection and tablets, prescribing information (Medication Guide revised 06/2026). National Library of Medicine DailyMed. DailyMed
- Victoza (liraglutide) injection, prescribing information. National Library of Medicine DailyMed. DailyMed
- Ozempic (semaglutide) injection, prescribing information. National Library of Medicine DailyMed. DailyMed
- U.S. Food and Drug Administration, “FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight Loss,” page current as of 1 October 2026. fda.gov
- U.S. Food and Drug Administration, “Compounding and the FDA: Questions and Answers,” page current as of 16 September 2025. fda.gov