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Metabolic & weight

Exenatide

Also called exendin-4 (synthetic), Byetta, Bydureon, Bydureon BCise

Exenatide was the first GLP-1 drug, a lab-made copy of a peptide found in Gila monster venom. It lowers blood sugar in type 2 diabetes. Its US brands Byetta and Bydureon BCise were discontinued in late 2024.

FDA-approvedApproved by the FDA for at least one use after large human trials.

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Drawn from its published sequence: 39 residues, one bead each.

Overview

Exenatide was the first GLP-1 drug, a lab-made copy of a peptide found in Gila monster venom. It lowers blood sugar in type 2 diabetes. Its US brands Byetta and Bydureon BCise were discontinued in late 2024.

How it works

Established: exenatide activates the GLP-1 receptor. This boosts insulin release only when blood sugar is high, lowers inappropriately high glucagon, and slows stomach emptying.

What research shows

  • In label trials with metformin and/or sulfonylurea, nausea occurred in 44% on Byetta vs 18% on placebo (FDA label, pooled RCTs).
  • Phase 3 Parkinson's disease trial (NCT04232969): no evidence of slowed progression over 96 weeks (Lancet 2025, as summarized by Wikipedia).

Doses studied in people

Study or labelDose usedSource
FDA label, Byetta, adults with type 2 diabetes5 mcg subcutaneously twice daily within 60 minutes before morning and evening meals; may increase to 10 mcg twice daily after 1 month1
FDA label, Bydureon BCise, adults and children 10+ with type 2 diabetes2 mg subcutaneously once every 7 days2

Label doses shown; both US brands have since been discontinued.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Weekly protocol

How the schedule looks week by week. Each chart says where it comes from: a prescribing label, a clinical trial, or a protocol commonly reported online.

Byetta label dosing

Prescribing label

One week

D1D2D3D4D5D6D7

Twice daily, within 60 minutes before the morning and evening meals · Subcutaneous injection

Dose by week

5 mcg twice dailyStarting · wk 1–4
10 mcg twice dailyMaintenance · wk 5+
Course
Ongoing
Note
The increase to 10 mcg after 1 month depends on clinical response. Both US exenatide brands have since been discontinued.
Source
BYETTA (exenatide) prescribing information (FDA, 2025)

Bydureon BCise label dosing

Prescribing label

One week

D1D2D3D4D5D6D7

Once every 7 days · Subcutaneous injection (extended-release)

Dose by week

2 mgwk 1+
Course
Ongoing
Note
Single fixed dose with no titration; approved for adults and children 10+ with type 2 diabetes.
Source
BYDUREON BCISE prescribing information (FDA, 2025)

Reference only, not a recommendation. Label and trial schedules were set for specific patients under medical supervision. Use the calculator only to understand the arithmetic.

Safety

  • Boxed warning (Bydureon BCise only): thyroid C-cell tumors in rats; contraindicated with personal/family history of medullary thyroid carcinoma or MEN 2 (label).
  • Acute pancreatitis, acute kidney injury from dehydration, severe GI reactions, gallbladder disease, drug-induced immune thrombocytopenia, hypersensitivity, and aspiration risk during anesthesia (labels).
  • Hypoglycemia mainly when combined with sulfonylureas or insulin (Byetta label: 35.7% with sulfonylurea at 10 mcg vs 3.3% placebo).
  • Common: nausea, vomiting, diarrhea, jitteriness, dizziness, headache (Byetta); injection-site nodules 10.5% and nausea 8.2% (Bydureon BCise).

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

History

Endocrinologist John Eng isolated exendin-4 from Gila monster venom in 1992 and patented it; Amylin Pharmaceuticals licensed it in 1996 and partnered with Eli Lilly in 2002. The FDA approved twice-daily Byetta in April 2005, followed by once-weekly Bydureon. AstraZeneca discontinued Byetta (October 25, 2024) and Bydureon BCise (October 28, 2024) in the US. A phase 3 trial in Parkinson's disease published in The Lancet in 2025 found no slowing of disease progression at 96 weeks.

Common questions

Is exenatide still available in the US?

Both US brands, Byetta and Bydureon BCise, were discontinued in October 2024 3. Byetta had been FDA-approved in 2005 for type 2 diabetes 4.

Where did exenatide come from?

It is based on exendin-4, a peptide isolated from Gila monster venom in 1992 4.

What doses did the FDA labels list?

Byetta's label listed 5 mcg injected twice daily before meals, with a possible increase to 10 mcg after a month 1. Bydureon BCise's label listed 2 mg once a week 2. Both are label figures for brands no longer sold in the US 3.

What are the side effects of exenatide?

Nausea was the most common, affecting 44% on Byetta vs 18% on placebo in label trials 1. The labels also warn of pancreatitis, kidney injury from dehydration, gallbladder disease and low blood sugar when combined with sulfonylureas or insulin 12.

Does exenatide help Parkinson's disease?

A phase 3 trial reported in The Lancet in 2025 found it did not slow Parkinson's progression over 96 weeks 4.

Is exenatide banned in sport?

It is not named on WADA's 2026 Prohibited List 5.

Related compounds

Metabolic & weightFDA-approvedFlashcard

Glucagon

Glucagon Emergency Kit · GlucaGen

Glucagon is a pancreatic hormone that does the opposite of insulin: it tells the liver to release stored sugar.

Metabolic & weightFDA-approvedFlashcard

Pramlintide

Symlin · SymlinPen

Pramlintide is a lab-made version of amylin, a hormone released with insulin after meals.

Metabolic & weightFDA-approvedFlashcard

Insulin (human insulin and analogs)

regular human insulin · Humulin R

Insulin is the hormone the pancreas makes to move sugar from the blood into the body's cells.

Sources

  1. BYETTA (exenatide) prescribing information (2025) FDA label
  2. BYDUREON BCISE (exenatide extended-release) prescribing information (2025) FDA label
  3. Discontinuation of Bydureon BCise and Byetta (UnitedHealthcare provider notice, Dec 2024) Regulatory
  4. Exenatide — Wikipedia (discovery history, CAS, Parkinson's trial summary) Reference
  5. WADA 2026 Prohibited List Regulatory

Last reviewed 2026-10-25 · How we research · Found an error? See our corrections policy.