Approved drugGLP-1 receptor agonist

Exenatide

Byetta, Bydureon BCise, synthetic exendin-4

Common dose: 5 → 10 mcg, 2× daily
Cycle: Continuous
Form: Ready-made pens

A synthetic copy of exendin-4, a 39-amino-acid peptide first found in the Gila monster lizard, that activates the GLP-1 receptor. It boosts insulin after meals, curbs glucagon and slows stomach emptying.

Evidence. FDA-approved for type 2 diabetes since 2005, when Byetta became the first GLP-1 drug. AstraZeneca discontinued Byetta and the weekly Bydureon BCise in the US in 2024, so a generic twice-daily pen is the only form sold now. EXSCEL (14,752 people) found the weekly form safe for the heart but not protective, and a 2025 Phase 3 trial found no benefit in Parkinson’s disease.

Status

Approval: Approved in the US for type 2 diabetes in adults. A generic twice-daily pen (approved November 2024) is the only form still sold; Byetta and the weekly Bydureon and Bydureon BCise (approved for adults and children 10 and older) are listed as discontinued.
Sport (WADA 2026): Not banned in sportNot named on the 2026 list, and S0 does not apply to an approved drug.

Sport status follows the WADA Prohibited List in force since January 1, 2026; athletes should confirm with their anti-doping organization. Checked October 5, 2026. Status of every compound.

How it works

Exenatide is a synthetic copy of exendin-4, a Gila monster peptide that partly matches human GLP-1, and it binds and switches on the GLP-1 receptor. When blood sugar is high it boosts insulin release, restoring the fast first wave of insulin that type 2 diabetes blunts, and it curbs glucagon, a hormone that raises blood sugar. It also slows stomach emptying, which slows the rise in sugar after meals, and it reduced food intake in animals and people.

LabelBased on the product label.

Not known

Whether the thyroid C-cell tumors the weekly form caused in rats matter for people is unknown. A small Parkinson’s trial hinted at effects in the brain, but a larger one found no benefit.

Protocol

Label

Byetta and generic

5 mcg twice daily within 60 minutes before the morning and evening meals (at least 6 hours apart); never after a meal. After 1 month it can rise to 10 mcg twice daily, based on response.

Label

Bydureon BCise

2 mg once weekly, any time of day, with or without meals. Discontinued in the US in 2024.

Frequency: Twice daily
Route: Subcutaneous injection
Timing: Within 60 minutes before the morning and evening meals, at least 6 hours apart. Not after a meal.
Cycle: Continuous. The label treats it as long-term therapy, not a cycle.
Continuous, shown over 26 weeks

Common protocols

The ways Exenatide is most often run, each tagged with where it comes from.

Twice daily (Byetta and generic)

Label

Dose: 5 mcg, rising to 10 mcg
How often: Twice daily, before morning and evening meals
How long: Long-term

10 mcg after 1 month only if needed. The generic pen is the only exenatide still sold in the US.

Once weekly (Bydureon BCise)

Label

Dose: 2 mg
How often: Once weekly
How long: Long-term

Extended-release microspheres, approved for adults and children 10 and older. Discontinued in the US in 2024; a powder vial can’t reproduce it.

Parkinson’s disease trials

Trial

Dose: 2 mg (extended-release)
How often: Once weekly
How long: 48–96 weeks

A 2017 Phase 2 trial (62 people) suggested slower worsening; the 2025 Phase 3 (194 people) found no benefit.

Label step-up schedule

Period	Dose
Weeks 1–4	5 mcg
Week 5 on (if needed)	10 mcg

Each dose is taken twice a day, before meals. The label raises it to 10 mcg after 1 month only if blood sugar needs it.

Taking it

Where it goes

Under the skin of the thigh, belly or upper arm (label). Rotate sites with every dose.

If you miss a dose

Twice-daily label: skip a missed dose and take the next one as scheduled; never take it after a meal. Bydureon BCise label (weekly): take a missed dose if the next one is at least 3 days away; otherwise skip it.

What to expect

Month 1
5 mcg twice daily to ease in. Nausea is most common early and usually fades.
Label
Week 30
Added to metformin and/or a sulfonylurea, HbA1c fell 0.8–0.9 points on 10 mcg vs a 0.1–0.2 point rise on placebo, and weight fell 1.6–2.8 kg.
Trial
Over the trials
3% stopped because of nausea and 1% because of vomiting, vs under 1% and none on placebo.
Label
Median 3.2 years (weekly form)
In EXSCEL, heart attack, stroke or cardiovascular death occurred in 11.4% vs 12.2% on placebo (HR 0.91), not a significant reduction.
Trial

Side effects and what to do

Nausea (label: 44% vs 18% on placebo, added to metformin and/or a sulfonylurea)

Dose-related and usually fades. The month at 5 mcg is meant to ease it.

Vomiting 13% and diarrhea 13% (label; placebo 4% and 6%)

Drink enough fluids. Heavy fluid loss can injure the kidneys.

Low blood sugar with a sulfonylurea (label: 14% at 5 mcg and 36% at 10 mcg vs 3% on placebo)

The label suggests lowering the sulfonylurea or insulin dose when starting.

Feeling jittery, dizziness, headache (label: 9% each vs 4–6% on placebo)

Usually mild. Shakiness can also be a sign of low blood sugar.

Antibodies to exenatide (label: low levels in 38% and high levels in 6% at 30 weeks)

About half of those with high levels (3% overall) had weaker blood-sugar control. The label suggests other treatment if control worsens.

Stop and get medical help

Severe belly pain that won’t go away (may spread to the back), face or throat swelling or trouble breathing, or unusual bleeding or bruising.

Who should avoid it

What its label rules out or warns about, most important first.

Past low platelets caused by exenatide: LabelRuled out. An immune reaction to exenatide can destroy platelets, the blood cells that help clotting, and cause serious, even fatal, bleeding; the label says never to restart it.
Serious allergy to exenatide: LabelRuled out after a severe reaction to exenatide or any ingredient; anaphylaxis and throat swelling have been reported. The label advises close monitoring after such a reaction to another GLP-1 drug.
History of medullary thyroid cancer or MEN 2: LabelRuled out only for the weekly forms (Bydureon and Bydureon BCise), which caused thyroid C-cell tumors in rats; MEN 2 is an inherited tumor syndrome. The twice-daily pen’s label has no such warning.
Severe kidney disease or dialysis: LabelNot recommended when creatinine clearance, a measure of kidney function, is under 30 mL/min, or on dialysis, where single doses were poorly tolerated. The label urges caution after a kidney transplant.
Severe gastroparesis (very slow stomach emptying): LabelNot recommended by the label. Exenatide slows stomach emptying, and severe stomach and gut side effects have been reported with GLP-1 drugs.
Planned surgery or deep sedation: LabelRare reports describe stomach contents entering the lungs under anesthesia, because the stomach empties slowly. The label says to tell the care team beforehand; whether pausing the drug helps is unknown.
Pregnancy: LabelHuman data are too limited to judge the risk, and animal studies suggest possible harm to the fetus. The label advises use only if the benefit justifies the risk.

Interactions

Only interactions stated on a product label or measured in a human study are listed.

Insulin or sulfonylureas (insulin-boosting diabetes pills such as glipizide): LabelLow blood sugar is much more likely: with a sulfonylurea it reached 36% at the higher dose vs 3% on placebo. The label advises considering lower insulin or sulfonylurea doses when starting.
Warfarin: LabelA study found no significant effect on INR, a clotting test, but INR rises, sometimes with bleeding, have been reported in use. The label advises more frequent INR checks after starting or changing exenatide.
Drugs that need a minimum level to work (such as birth-control pills and antibiotics): LabelTaken 30 minutes after exenatide, a birth-control pill’s peak estrogen level fell 45%. The label advises taking such drugs at least 1 hour before the injection, or with a meal when exenatide isn’t given.
Other oral medicines (such as lovastatin, digoxin or acetaminophen): LabelSlower stomach emptying delays and can reduce absorption: lovastatin exposure fell about 40% and acetaminophen’s peak level up to 56%. The label urges caution where slower absorption matters.
Other exenatide products: LabelThe labels say not to combine exenatide products, such as the twice-daily pen and a weekly form.

Label: a product label rules it out, warns about it or lists the interaction. This isn’t a complete list: a pharmacist or doctor can check a specific medicine or condition.

Tracking and pairing

Worth tracking

Blood sugar, especially with a sulfonylurea or insulin
HbA1c
Kidney function if vomiting or diarrhea is heavy
INR if you take warfarin
Unusual bruising or bleeding

Often paired with

Usually run on its own.

Human studies

5 key published human studies, with how many people took part. Animal studies aren’t listed here.

201714,752 people

Heart attack, stroke or cardiovascular death in 11.4% vs 12.2% on placebo (HR 0.91): noninferior but not superior, in type 2 diabetes with or without heart disease.

Design
Randomized double-blind placebo-controlled trial
Dose
2 mg extended-release once weekly
Length
Median 3.2 years

Holman et al., N Engl J Med 2017 (EXSCEL), PMID 28910237
2005733 people

HbA1c fell 0.8 points on 10 mcg and 0.6 on 5 mcg vs a 0.2-point rise on placebo; weight fell 1.6 kg vs 0.9 kg on placebo.

Design
Randomized double-blind placebo-controlled trial
Dose
5 or 10 mcg twice daily, added to metformin and a sulfonylurea
Length
30 weeks

Kendall et al., Diabetes Care 2005, PMID 15855571
2005336 people

HbA1c fell 0.78 points on 10 mcg and 0.40 on 5 mcg vs a 0.08-point rise on placebo; weight fell 2.8 kg on 10 mcg, with no more low blood sugar than placebo.

Design
Randomized triple-blind placebo-controlled trial
Dose
5 or 10 mcg twice daily, added to metformin
Length
30 weeks

DeFronzo et al., Diabetes Care 2005, PMID 15855572
2025194 people

Off-medication motor scores worsened by 5.7 points vs 4.5 on placebo (p=0.47): no sign that exenatide slows Parkinson’s disease.

Design
Phase 3 randomized double-blind placebo-controlled trial in Parkinson’s disease
Dose
2 mg extended-release once weekly
Length
96 weeks

Vijiaratnam et al., Lancet 2025 (Exenatide-PD3), PMID 39919773
201762 people

At 60 weeks off-medication motor scores improved 1.0 point vs worsening 2.1 on placebo (adjusted difference 3.5 points, p=0.03); the larger Phase 3 did not confirm it.

Design
Phase 2 randomized double-blind placebo-controlled trial in Parkinson’s disease (single center)
Dose
2 mg extended-release once weekly
Length
48 weeks, plus 12-week washout

Athauda et al., Lancet 2017, PMID 28781108

All human studies on Vial Guide

Limits of the evidence

The twice-daily pen’s evidence rests mainly on trials of 30 weeks or less, each with a few hundred adults, most taking metformin or a sulfonylurea. Long-term heart data come from EXSCEL, which tested the weekly form, not the pen, for a median 3.2 years. The pen isn’t approved for weight loss or for anyone under 18; in a trial of 120 children aged 10–17 with type 2 diabetes, it didn’t improve blood sugar.

How it’s supplied

Ready-made pens of 5 mcg or 10 mcg per dose (250 mcg/mL). The pen measures each dose, so there’s nothing to mix or draw up.

Exenatide comes as ready-made pens, not powder: 300 mcg in 1.2 mL for 5 mcg doses or 600 mcg in 2.4 mL for 10 mcg doses, both 250 mcg/mL. The weekly microsphere form (Bydureon BCise) can’t be made from a vial at all.

Datasheet

Half-life: about 2.4 hours LabelTwice-daily pen, subcutaneous, in adults with type 2 diabetes: levels peak about 2.1 hours after a dose and stay measurable for about 10 hours. The weekly microsphere form (Bydureon BCise) released it slowly, reaching steady levels after about 10 weeks.
Type: Peptide, 39 amino acids
Molecular weight: 4,186.6 g/mol
Formula: C₁₈₄H₂₈₂N₅₀O₆₀S
Sequence: HGEGTFTSDLSKQMEEEAVRLFIEWLKNGGPSSGAPPPS-NH2
Storage before use: Not a powder: pens hold a ready-made solution. Before first use, refrigerate at 2–8 °C and protect from light; never freeze.
After mixing or opening: After first use, keep at or below 25 °C and discard the pen 30 days after first use. Bydureon BCise (discontinued) was stored flat in the fridge and could stay at up to 30 °C for 4 weeks in total.

Half-life: Exenatide injection label rev. 05/2026, section 12.3; Bydureon BCise label rev. 05/2025, section 12.3
Molecule: Exenatide injection label rev. 05/2026, section 11 (sequence, formula, MW); KEGG D04121; PubChem CID 45588096
Storage: Label Exenatide injection label rev. 05/2026, section 16.2; Bydureon BCise label rev. 05/2025, section 16

Every compound side by side: the half-life chart and the storage chart.

Cautions

Pancreatitis, gallbladder disease, and kidney injury from dehydration are listed risks. Not recommended with severe kidney disease (creatinine clearance under 30 mL/min).
Low blood sugar is common with a sulfonylurea (36% at 10 mcg vs 3% on placebo); the label suggests lowering the sulfonylurea or insulin dose.
A rare immune reaction can destroy platelets and cause serious, even fatal, bleeding. Anyone who has had it must not use exenatide again.
Slows stomach emptying: the label says to take birth-control pills and antibiotics at least 1 hour before a dose. Tell the care team before surgery or sedation.
The weekly forms (Bydureon, Bydureon BCise) carried a boxed warning for thyroid C-cell tumors; the twice-daily pen does not.

Questions

What is exenatide?

How does exenatide work?

Is exenatide FDA-approved?

Approved in the US for type 2 diabetes in adults. A generic twice-daily pen (approved November 2024) is the only form still sold; Byetta and the weekly Bydureon and Bydureon BCise (approved for adults and children 10 and older) are listed as discontinued.

What is the usual exenatide dose?

From the label (Byetta and generic): 5 mcg twice daily within 60 minutes before the morning and evening meals (at least 6 hours apart); never after a meal. After 1 month it can rise to 10 mcg twice daily, based on response. Bydureon BCise: 2 mg once weekly, any time of day, with or without meals. Discontinued in the US in 2024. These are the amounts sources reference, not recommendations.

How is exenatide given?

Ready-made pens of 5 mcg or 10 mcg per dose (250 mcg/mL), injected under the skin. Within 60 minutes before the morning and evening meals, at least 6 hours apart. Not after a meal. The pen measures each dose, so there’s nothing to mix.

Who should avoid exenatide?

Past low platelets caused by exenatide: Ruled out. An immune reaction to exenatide can destroy platelets, the blood cells that help clotting, and cause serious, even fatal, bleeding; the label says never to restart it. Serious allergy to exenatide: Ruled out after a severe reaction to exenatide or any ingredient; anaphylaxis and throat swelling have been reported. The label advises close monitoring after such a reaction to another GLP-1 drug. History of medullary thyroid cancer or MEN 2: Ruled out only for the weekly forms (Bydureon and Bydureon BCise), which caused thyroid C-cell tumors in rats; MEN 2 is an inherited tumor syndrome. The twice-daily pen’s label has no such warning. The “Who should avoid it” section lists 4 more groups and 5 interactions.

What is the half-life of exenatide?

About 2.4 hours, according to the prescribing information. Twice-daily pen, subcutaneous, in adults with type 2 diabetes: levels peak about 2.1 hours after a dose and stay measurable for about 10 hours. The weekly microsphere form (Bydureon BCise) released it slowly, reaching steady levels after about 10 weeks.

How should exenatide be stored?

Not a powder: pens hold a ready-made solution. Before first use, refrigerate at 2–8 °C and protect from light; never freeze. After first use, keep at or below 25 °C and discard the pen 30 days after first use. Bydureon BCise (discontinued) was stored flat in the fridge and could stay at up to 30 °C for 4 weeks in total.

Is exenatide banned in sport?

No. Not named on the 2026 list, and S0 does not apply to an approved drug.

Has exenatide been studied in people?

Yes. The human studies section lists 5 published studies. The largest, from 2017, included 14,752 people. Heart attack, stroke or cardiovascular death in 11.4% vs 12.2% on placebo (HR 0.91): noninferior but not superior, in type 2 diabetes with or without heart disease.

Sources

Exenatide injection prescribing information (Amneal), rev. 05/2026
Bydureon BCise prescribing information, rev. 05/2025 (AstraZeneca; discontinued)
Drugs@FDA: Byetta, Bydureon and Bydureon BCise listed as discontinued (2026)
Holman et al., EXSCEL trial (NEJM 2017) PMID 28910237
Vijiaratnam et al., Exenatide-PD3 trial (Lancet 2025) PMID 39919773

For the protocol details

Exenatide injection prescribing information (Amneal), rev. 05/2026, sections 2, 5, 6 and 7
Bydureon BCise prescribing information, rev. 05/2025, sections 2 and 12.3
Kendall et al., exenatide with metformin and a sulfonylurea (Diabetes Care 2005) PMID 15855571
DeFronzo et al., exenatide with metformin (Diabetes Care 2005) PMID 15855572
Buse et al., exenatide with a sulfonylurea (Diabetes Care 2004) PMID 15504997
Athauda et al., exenatide in Parkinson’s disease, Phase 2 (Lancet 2017) PMID 28781108

For how it works, who should avoid it and the limits of the evidence

Exenatide injection prescribing information, sections 1, 4, 5, 7, 8 and 12 (Amneal, DailyMed, rev. 05/2026)
Bydureon BCise prescribing information, boxed warning and sections 1 and 4 (AstraZeneca, openFDA, rev. 05/2025; discontinued)

By Vial Guide editorsLast reviewed October 5, 2026

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