Semaglutide vs liraglutide
Last updated: October 2, 2026 · 5 min read · By the Grey Peptides Editorial Board
- In the one head-to-head weight trial, STEP 8, weekly semaglutide cut body weight by 15.8% over 68 weeks against 6.4% for daily liraglutide, a gap of 9.4 percentage points.
- For type 2 diabetes, oral semaglutide matched injected liraglutide on blood sugar in PIONEER 4 and took off a little more weight.
- Both have outcome trials showing fewer heart attacks, strokes and cardiovascular deaths than placebo, but in different populations, so those results do not rank them.
Side by side
Semaglutide High and liraglutide High are both GLP-1 receptor agonists: they mimic a gut hormone that raises insulin after meals, slows the stomach and reduces appetite. The practical difference starts with the half-life. Semaglutide lasts about a week in the body and liraglutide about 13 hours, which is why semaglutide is injected once a week and liraglutide once a day. The table is read straight from our two encyclopedia entries; each dosage page lists the labelled doses with their sources.
| Field | Semaglutide | Liraglutide |
|---|---|---|
| Encyclopedia entry | Semaglutide Full entry | Liraglutide Full entry |
| Molecule class | Peptide | Peptide |
| Category | Metabolic | Metabolic |
| FDA status | FDA Approved | FDA Approved |
| Approved elsewhere | None recorded | None recorded |
| Evidence grade | High | High |
| Half-life | ≈ 7 days | ≈ 13 hours |
| Formula | C187H291N45O59 | C172H265N43O51 |
| Molecular weight | 4,113.6 g/mol | 3,751.2 g/mol |
| WADA 2026 | Not on the 2026 List | Not on the 2026 List |
| WADA 2027 | Not on the 2027 List | Not on the 2027 List |
| In one line | A once-weekly GLP-1 receptor agonist FDA-approved for type 2 diabetes and chronic weight management. | The first once-daily GLP-1 analog to be FDA-approved for both type 2 diabetes (Victoza) and chronic weight management (Saxenda). |
| Mechanism | Agonist at the GLP-1 receptor. Enhances glucose-dependent insulin secretion, suppresses inappropriate glucagon, slows gastric emptying, and acts centrally to reduce appetite via hypothalamic and area postrema pathways. Weight loss is driven primarily by the central appetite-suppressing effect rather than the peripheral metabolic actions. | Agonist at the GLP-1 receptor. Enhances glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and acts on hypothalamic appetite centers. The daily dosing requirement reflects its shorter half-life compared with semaglutide — which also means faster onset and offset of both therapeutic and adverse effects. |
| Sources in the entry | 14 | 10 |
| Study cards | 8 | 8 |
| Dosage page | Dosage page | Dosage page |
Weight loss: the STEP 8 trial
Most comparisons between these two drugs are made across separate trials, which is unreliable. STEP 8 is the exception: it put them in the same trial 1. It randomized 338 adults with overweight or obesity, about four in five of them women, with an average weight of 104.5 kg, to weekly semaglutide 2.4 mg, daily liraglutide 3.0 mg or placebo, alongside diet and exercise counselling, for 68 weeks 1.
Average weight change was 15.8% with semaglutide and 6.4% with liraglutide, a difference of 9.4 percentage points; the pooled placebo groups lost 1.9% 1. The gap widened at the higher thresholds people care about: 70.9% of semaglutide users lost at least 10% of their weight against 25.6% on liraglutide, and 55.6% lost at least 15% against 12.0% 1. That is as clear a result as head-to-head obesity trials produce.
Type 2 diabetes: PIONEER 4
For type 2 diabetes the most direct comparison uses the oral form of semaglutide. PIONEER 4 compared oral semaglutide with liraglutide injections and placebo in adults already taking metformin 2. After 26 weeks, HbA1c, the long-term blood-sugar measure, fell 1.2 percentage points on oral semaglutide, 1.1 on liraglutide and 0.2 on placebo: oral semaglutide was non-inferior to liraglutide, and better than placebo 2. It also took off more weight, 4.4 kg against 3.1 kg 2.
So in diabetes the blood-sugar effects were close, and the weight difference was smaller than in STEP 8, partly because the doses were lower and the trial shorter.
Heart outcomes
Both drugs have large cardiovascular outcome trials, each against placebo rather than against each other. In LEADER, 9,340 people with type 2 diabetes and high cardiovascular risk took liraglutide or placebo; the main outcome, a composite of cardiovascular death, heart attack and stroke, occurred in 13.0% against 14.9% (hazard ratio 0.87), and cardiovascular deaths were fewer (hazard ratio 0.78) 3. In SUSTAIN-6, injected semaglutide in type 2 diabetes cut the same composite from 8.9% to 6.6% (hazard ratio 0.74) 4. In SELECT, semaglutide 2.4 mg in 17,604 people with obesity and cardiovascular disease but no diabetes cut it from 8.0% to 6.5% (hazard ratio 0.80), though side effects led 16.6% to stop the drug against 8.2% on placebo 5.
These trials enrolled different people for different lengths of time, so the hazard ratios cannot be lined up to declare a winner. What they establish is that both drugs lowered cardiovascular events in the populations studied.
How the differences add up
On the evidence, semaglutide produces more weight loss than liraglutide when the two are tested together, and a weekly injection replaces a daily one. For blood sugar in type 2 diabetes, the two are much closer. Liraglutide has the longer track record and, being the older drug, a longer list of studies behind it; semaglutide has the larger effect on weight and an outcome trial in people without diabetes.
Neither result says which is right for a particular person: that depends on the goal, other conditions, cost and how each is tolerated, which is a conversation for a prescriber. Our entries for semaglutide and liraglutide cover each in full.
Status as of October 2, 2026
Both are FDA-approved, in several branded forms each; the table's FDA row and each entry's dosage page give the details. Approval status is read from our dataset as of October 2, 2026.
Frequently asked questions
Is semaglutide better than liraglutide for weight loss?
In the STEP 8 head-to-head trial, weekly semaglutide 2.4 mg cut weight by 15.8% over 68 weeks against 6.4% for daily liraglutide 3.0 mg.
Are they equally good for type 2 diabetes?
Closer. In PIONEER 4, oral semaglutide lowered HbA1c by 1.2 points against 1.1 for liraglutide over 26 weeks, and took off slightly more weight.
Do both protect the heart?
Both lowered cardiovascular events against placebo in their own outcome trials (LEADER for liraglutide; SUSTAIN-6 and SELECT for semaglutide), but those trials cannot be compared directly.
Related on Grey Peptides
Sources
- Rubino, D. M., Greenway, F. L., Khalid, U., et al. (2022). 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, 327(2), 138-150. PMID: 35015037
- Pratley, R., Amod, A., Hoff, S. T., et al. (2019). Oral semaglutide versus subcutaneous liraglutide and placebo in type 2 diabetes (PIONEER 4): a randomised, double-blind, phase 3a trial. Lancet, 394(10192), 39-50. PMID: 31186120
- Marso, S. P., Daniels, G. H., Brown-Frandsen, K., et al. (2016). Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes. N Engl J Med, 375(4), 311-22. PMID: 27295427
- Marso, S. P., Bain, S. C., Consoli, A., et al. (2016). Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes. N Engl J Med, 375(19), 1834-1844. PMID: 27633186
- Lincoff, A. M., Brown-Frandsen, K., Colhoun, H. M., et al. (2023). Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. N Engl J Med, 389(24), 2221-2232. PMID: 37952131
Educational information, not medical advice. Each dose in this guide names its source, an approved label or a published study. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose.
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