Skip to content
DE

Exenatide: the first GLP-1 medicine and its successors

Clinical review pending

Exenatide is used to control blood glucose in type 2 diabetes. Its development, how it works, its risks and how it differs from newer medicines.

What is exenatide?

Exenatide is a GLP-1 receptor agonist 1. The peptide mimics the body’s gut hormone GLP-1. It is a synthetic copy of exendin-4, originally discovered in the venom of the Gila monster, a large venomous lizard native to the southwestern United States.

Exenatide was developed by Amylin Pharmaceuticals and Eli Lilly and later marketed by AstraZeneca. It reached the market as Byetta, injected twice daily, and as Bydureon BCise, injected once weekly.

How exenatide was developed

In the early 1990s, endocrinologist John Eng studied Gila monster venom 2. He identified exendin-4, a hormone-like peptide that closely resembles human GLP-1 but remains in the body much longer. Human GLP-1 is broken down within minutes; the lizard peptide remained active for hours. This made it an interesting drug candidate.

That discovery led to exenatide. Byetta became the first GLP-1 medicine to receive FDA approval in 2005. It marked the beginning of a drug class whose later members include liraglutide, semaglutide and the dual agonist tirzepatide. The weekly Bydureon formulation followed in 2012. According to the source article, AstraZeneca discontinued US sales of Byetta and Bydureon BCise in 2024 for commercial reasons 3. It states that a generic version of Byetta was introduced in May 2025, keeping twice-daily exenatide available. Source Source Source

How does exenatide work?

Exenatide activates the GLP-1 receptor, mimicking a gut hormone released after meals. Insulin release increases in response to glucose levels 1, so the medicine carries a low risk of hypoglycemia when used alone. It also reduces glucagon, slows stomach emptying and reduces appetite. Source Source

Exenatide is based on exendin-4 and resists the enzyme that rapidly breaks down natural GLP-1. It therefore remains active longer than human GLP-1 and can be given twice daily. The extended-release Bydureon formulation encloses the peptide in tiny microspheres. These release it slowly, allowing weekly dosing 1. Trials have shown moderate reductions in A1c and some weight loss. Source

Is exenatide FDA-approved?

Byetta was approved in 2005 as the first GLP-1 medicine; the weekly Bydureon formulation followed in 2012. According to the source article, AstraZeneca discontinued both products in the United States in 2024 for commercial reasons, not because of a safety issue. The source states that twice-daily exenatide continues to be sold there as a generic.

What is exenatide prescribed for?

Exenatide is used alongside diet and exercise to improve blood glucose control in adults with type 2 diabetes. It is not a treatment for type 1 diabetes. The long-acting Bydureon formulation must not be used in people with a personal or family history of medullary thyroid carcinoma 1, or with multiple endocrine neoplasia type 2.

What side effects are possible?

Gastrointestinal symptoms, particularly nausea, are the most common. Reported effects include:

  • Nausea

  • Vomiting

  • Diarrhea

  • Shakiness or jitteriness

  • Dizziness

  • Headaches

  • Reduced appetite

Less common but more serious risks include:

  • Pancreatitis, or inflammation of the pancreas Source

  • Hypoglycemia, particularly when combined with a sulfonylurea

  • Acute kidney injury, often associated with fluid loss from vomiting or diarrhea Source Source

  • Gallbladder problems, including gallstones Source

  • Injection-site nodules with the extended-release formulation

  • For the long-acting Bydureon formulation, US prescribing information carries a boxed warning about thyroid C-cell tumors based on rodent studies 1. The twice-daily Byetta formulation does not carry this warning.

How does exenatide differ from semaglutide, tirzepatide and liraglutide?

Exenatide was the first GLP-1 medicine. Newer medicines have surpassed it in many settings in terms of effectiveness and convenience.

The differences are particularly noticeable in weight outcomes. Exenatide produces relatively modest reductions in blood glucose and body weight. The newer medicines achieved greater average weight loss in their weight-management trials, as shown in the table.

These figures come from different studies and do not allow a direct comparison. Overall, however, they point to stronger effects of newer medicines on weight and blood glucose.

Exenatide, liraglutide and semaglutide act at the GLP-1 receptor. Tirzepatide also activates the receptor for the gut hormone GIP 7, which may contribute to its greater effect. Exenatide is based on the lizard peptide exendin-4; liraglutide and semaglutide were developed from human GLP-1.

Administration has also changed. Exenatide started with twice-daily injections and later gained a weekly formulation. Liraglutide is injected daily; semaglutide and tirzepatide are injected weekly. Semaglutide is also available as a daily tablet.

Newer medicines are also used beyond blood glucose control. The source article cites cardiovascular indications for liraglutide and semaglutide, as well as approvals for semaglutide in chronic kidney disease and fatty liver disease, and for tirzepatide in obstructive sleep apnea. By contrast, according to the source, the exenatide brands were discontinued in the United States in 2024. Exenatide thus belongs to the first generation, while newer options have taken over many of its former uses. Source Source Source

Studies at a glance

Medicine Average weight loss in the cited studies
Liraglutide, given daily, based on human GLP-1 About 8% [4]
Semaglutide, given weekly About 15% [5]
Tirzepatide Up to about 22.5% [6]

Source Source Source

References provided in the source article

Sources: FDA prescribing information for Bydureon BCise (exenatide) and Mounjaro (tirzepatide); the SCALE (Pi-Sunyer et al., 2015, DOI: 10.1056/NEJMoa1411892 4 ), STEP 1 (Wilding et al., 2021, DOI: 10.1056/NEJMoa2032183 5 ), and SURMOUNT-1 (Jastreboff et al., 2022, DOI: 10.1056/NEJMoa2206038 6 ) weight-management trials in the New England Journal of Medicine and a review of the development of exenatide from Gila monster venom, indexed on PubMed; and the 2024 U.S. discontinuation notice.

Provenance and editorial review status

Adapted for Nutrient Desk from the source article. The claims and source attributions in the original text still require clinical review. This draft has not been cleared for indexing.