Exenatide
Byetta · Bydureon · Exendin-4 · AC2993
First-in-class GLP-1 RA (Byetta BID / Bydureon weekly). Synthetic exendin-4 from Heloderma. Modest weight loss. A lyophilized cake is not Bydureon microspheres.
Use-case scores
0–10 against the evidence we have, not a gym ranking. Hidden domains do not apply here.
- Metabolic / weight7.5/10
Approved T2D since 2005. Ceiling 9 for approval; haircut because weight loss is modest, IR is twice daily, and a research exendin-4 vial is not Byetta.
Compound card
- Sequence
- Exendin-4, 39-aa (53% homology to human GLP-1)
- Class
- First-in-class GLP-1 RA (Byetta BID / Bydureon weekly)
- Formula
- C184H282N50O60S
- Status
- Not FDA-approved · research use
How it works
Exenatide (Byetta® / Bydureon®) was the first GLP-1 receptor agonist approved by the FDA (2005). It is a synthetic version of exendin-4, a peptide found in the Gila monster lizard's saliva that has 53% homology to human GLP-1. Exenatide acts on GLP-1 receptors to enhance glucose-dependent insulin secretion, suppress glucagon, slow gastric emptying, and reduce appetite. The extended-release version (Bydureon BCise) uses microspheres for once-weekly administration. Weight loss averages 2-4 kg versus semaglutide's 15-17%.
Source: PMID: 15765106 (AC2993 Phase 3)
Research Use Cases
- ✓Type 2 Diabetes: High
- ✓Weight Management: Moderate
Dosing
| Phase | Dose | Frequency | Notes |
|---|---|---|---|
| Immediate-Release (Byetta) | 5 mcg, then 10 mcg | Twice daily (SC, within 60 min before meals) | 5 mcg for 4 weeks, then 10 mcg if tolerated. |
| Extended-Release (Bydureon) | 2 mg | Once weekly (SC) | Weekly microsphere injection. Do not crush or mix with other medications. |
Administration
Timeline
Who it is for
Type 2 Diabetes
HighFDA-approved. First-in-class GLP-1 agonist - well-established safety profile since 2005.
Weight Management
ModerateModest weight loss. Largely superseded by semaglutide and tirzepatide for weight primary goals.
Reconstitution
| Vial | Water | Concentration | Example dose |
|---|---|---|---|
| Pen (Byetta / Bydureon) | n/a (device) | Device-labeled | Follow the pen. IR is micrograms twice daily, not milligrams weekly. |
Change vial size or water volume? Open the reconstitution calculator.
Safety & Considerations
FDA-approved. Pancreatitis risk - discontinue and do not restart if suspected. MTC/MEN 2 contraindication (class effect). Common: nausea, vomiting, diarrhea. Injection site nodules with extended-release form.
Regulatory & Legal Status
Not currently on the WADA 2026 Prohibited List. Policies may change - verify before competition.
Research Chemical
US Compounding: Not eligible / not available
⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.
Limits of current evidence
- Byetta is 5–10 mcg twice daily. That is not a milligram-weekly research chart.
- Bydureon is a microsphere depot. Do not copy its 2 mg weekly onto a simple lyophilized cake.
- Same MTC/MEN2 class warning as later GLP-1 RAs.
Verdict
Exenatide is the Gila-monster-era GLP-1 that started the class. Byetta and Bydureon are labeled pens. It is not Wegovy. Do not treat a 2 mg cake as Bydureon microspheres.
Interactions & Contraindications
FDA-approved. Pancreatitis risk - discontinue and do not restart if suspected. MTC/MEN 2 contraindication (class effect). Common: nausea, vomiting, diarrhea. Injection site nodules with extended-release form.
Frequently Asked Questions
Is exenatide still used when semaglutide exists?▼
What is the difference between Byetta and Bydureon?▼
References
- Blonde L et al. “"Exenatide (exendin-4) in the treatment of type 2 diabetes".” Clinical Therapeutics (2006). PMID: 16860174
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