Exenatide vs liraglutide
Last updated: October 2, 2026 · 5 min read · By the Grey Peptides Editorial Board
- Exenatide and liraglutide were the first two GLP-1 drugs. Exenatide is based on exendin-4, a peptide from Gila monster venom; liraglutide is a modified human GLP-1.
- In their head-to-head trial, LEAD-6, daily liraglutide lowered HbA1c more than twice-daily exenatide, with similar weight loss, less lasting nausea and less minor low blood sugar.
- Only liraglutide went on to a weight-management approval (Saxenda) and a positive cardiovascular trial (LEADER). As of October 2, 2026, both are approved in the US, and liraglutide is available as a generic.
Side by side
Exenatide High and liraglutide High both activate the GLP-1 receptor, raising insulin when blood sugar is high, slowing the stomach and curbing appetite. The LEAD-6 investigators describe the difference in origin: exenatide is an exendin-based GLP-1 receptor agonist, while liraglutide is a human GLP-1 analogue 1. The practical difference is how long each lasts: exenatide twice daily (Byetta) has a half-life of about 2.4 hours, liraglutide about 13 hours, which is why it is injected once a day 2. Exenatide was later reformulated for weekly dosing (Bydureon). The table is read from our encyclopedia entries.
| Field | Exenatide | Liraglutide |
|---|---|---|
| Encyclopedia entry | Exenatide 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 | ≈ 2.4 hours | ≈ 13 hours |
| Formula | C184H282N50O60S | C172H265N43O51 |
| Molecular weight | 4,186.6 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 | The first GLP-1 receptor agonist (Byetta, 2005), a synthetic copy of a Gila monster venom peptide: safe for the heart in EXSCEL without proving benefit, outperformed by weekly semaglutide head to head, and negative in a phase 3 Parkinson's trial. | 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: glucose-dependent insulin secretion, lower glucagon and slower gastric emptying, which is why Byetta is injected within an hour before the two main meals. Its 2.4-hour half-life (label) gives twice-daily dosing; the weekly forms used slow-release microspheres. | 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 | 13 | 10 |
| Study cards | 11 | 8 |
| Dosage page | None | Dosage page |
LEAD-6: the direct comparison
LEAD-6 randomised 464 adults with type 2 diabetes, already on metformin, a sulphonylurea or both, in 15 countries, to liraglutide 1.8 mg once a day or exenatide 10 micrograms twice a day for 26 weeks 1. HbA1c, which started at 8.2% on average, fell by 1.12 percentage points on liraglutide against 0.79 on exenatide, and more people on liraglutide reached an HbA1c under 7% (54% against 43%). Liraglutide lowered fasting glucose more, but exenatide controlled the rise in glucose after breakfast and dinner better, a consequence of its short action around meals. Weight fell similarly, by 3.24 kg against 2.87 kg. Nausea was less persistent on liraglutide, and minor hypoglycaemia less frequent: 1.93 against 2.60 events per patient per year 1. The trial was open label and funded by Novo Nordisk, which makes liraglutide.
Weekly exenatide and the newer drugs
The weekly form of exenatide answered the twice-daily schedule, but it was soon outpaced. In SUSTAIN 3, over 56 weeks, weekly semaglutide 1.0 mg lowered HbA1c by 1.5 points against 0.9 on extended-release exenatide 2.0 mg, and weight by 5.6 kg against 1.9 kg 3. Liraglutide, in turn, was outpaced by semaglutide for weight in STEP 8, as our semaglutide vs liraglutide comparison sets out. Both of the first-generation drugs remain in use, but neither is now the most potent option in its class.
Heart and kidney outcomes
Both drugs have large cardiovascular outcome trials, with different results. EXSCEL gave weekly exenatide 2 mg or placebo to 14,752 people with type 2 diabetes, 73% with previous cardiovascular disease, for a median 3.2 years; major cardiovascular events occurred in 11.4% against 12.2% 4. LEADER randomised 9,340 adults with type 2 diabetes and high cardiovascular risk to liraglutide up to 1.8 mg daily or placebo for 3.5 to 5 years 5, and a prespecified analysis found a 22% reduction in a composite kidney outcome (hazard ratio 0.78) 6.
Weight, and the trials beyond diabetes
Liraglutide is the one that became a weight-loss drug. At 3.0 mg a day, sold as Saxenda since 2014, it lowered weight by 8.0% against 2.6% on placebo over 56 weeks in SCALE, in 3,731 adults without diabetes 7. Exenatide has no weight-management approval in our records 2.
Exenatide has been tested in brain diseases, with a sobering result. After a small positive phase 2 study in Parkinson's disease, a 96-week phase 3 trial at six UK hospitals found off-medication motor scores worsened by 5.7 points on weekly exenatide 2 mg and 4.5 points on placebo, no benefit (p = 0.47), though it was safe and well tolerated 8.
How the differences add up (as of October 2, 2026)
Liraglutide beat twice-daily exenatide on blood sugar in the one direct comparison, with similar weight loss and better tolerability, and it went on to a positive cardiovascular outcome trial, a weight-management approval and, in 2024, generic versions 2. Exenatide's advantages are narrower: its twice-daily form acts sharply around meals, and its weekly form needs only one injection a week. Byetta was approved in 2005, Bydureon in 2012 and Bydureon BCise in 2017; Victoza in 2010 and Saxenda in 2014 2. Both are prescription drugs, and the doses here are those studied in trials, not recommendations.
Frequently asked questions
Is liraglutide better than exenatide?
In LEAD-6, liraglutide 1.8 mg daily lowered HbA1c by 1.12 points against 0.79 on exenatide 10 micrograms twice daily over 26 weeks, with similar weight loss and less persistent nausea.
Which causes more weight loss, Byetta or Victoza?
In LEAD-6 they were similar: 3.24 kg on liraglutide and 2.87 kg on exenatide over 26 weeks. Only liraglutide went on to a weight-management approval, at 3.0 mg as Saxenda.
Does exenatide help Parkinson's disease?
No, on current evidence. A 96-week phase 3 trial found no slowing of motor decline on weekly exenatide compared with placebo.
Related on Grey Peptides
Sources
- Buse, J. B., et al. (2009). Liraglutide once a day versus exenatide twice a day for type 2 diabetes: a 26-week randomised, parallel-group, multinational, open-label trial (LEAD-6). Lancet, 374(9683), 39-47. PMID: 19515413
- Grey Peptides dataset records for both compounds (status, half-life and studied doses as sourced on each entry); read October 2, 2026.
- Ahmann, A. J., et al. (2018). Efficacy and Safety of Once-Weekly Semaglutide Versus Exenatide ER in Subjects With Type 2 Diabetes (SUSTAIN 3): A 56-Week, Open-Label, Randomized Clinical Trial. Diabetes Care, 41(2), 258-266. PMID: 29246950
- Holman, R. R., et al. (2017). Effects of Once-Weekly Exenatide on Cardiovascular Outcomes in Type 2 Diabetes. N Engl J Med, 377(13), 1228-1239. PMID: 28910237
- Marso, S. P., et al. (2016). Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes. N Engl J Med, 375(4), 311-22. PMID: 27295427
- Mann, J. F. E., et al. (2017). Liraglutide and Renal Outcomes in Type 2 Diabetes. N Engl J Med, 377(9), 839-848. PMID: 28854085
- Pi-Sunyer, X., et al. (2015). A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management. N Engl J Med, 373(1), 11-22. PMID: 26132939
- Vijiaratnam, N., et al. (2025). Exenatide once a week versus placebo as a potential disease-modifying treatment for people with Parkinson's disease in the UK: a phase 3, multicentre, double-blind, parallel-group, randomised, placebo-controlled trial. Lancet, 405(10479), 627-636. PMID: 39919773
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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