GLP-1 Overdose: What Happens and What to Do

Most GLP-1 overdoses are accidents, usually a dose drawn wrong from a compounded vial, and most cause severe nausea and vomiting rather than lasting harm. The danger is in how long it lasts. Semaglutide (Ozempic, Wegovy, Rybelsus) has a half-life of about a week and tirzepatide (Mounjaro, Zepbound) about five days, so the drug cannot be flushed out and symptoms can run for days. Every one of these labels tells you what to do first: call the Poison Help line at 1-800-222-1222, free and open around the clock.^[3][7][15] Call 911 instead if the person has collapsed, had a seizure, is struggling to breathe or cannot be woken.^[15]

If you took too much: what to do now

1. Call Poison Help at 1-800-222-1222. It reaches your local poison center, staffed by specialists, at no cost, for emergencies and for “is this a problem?” questions alike.^[15] Each GLP-1 label names this line for overdose.^[3][6]
2. Call 911 if the person has collapsed, had a seizure, has trouble breathing or cannot be woken.^[15]
3. Have the vial, pen or box in hand. The specialist will want the drug, the concentration printed on the label (for a vial, in mg/mL), how many units or clicks were injected, and when.
4. Tell them about other diabetes drugs. Insulin or a sulfonylurea such as glipizide or glimepiride raises the risk of low blood sugar.^[3][7]
5. Do not take the next dose until a clinician has told you when to resume. The extra drug from an overdose is still working through the following week.^[3][7]

What the FDA labels say about overdose

Each approved GLP-1 label has a short section titled “Overdosage.” None names an antidote, because there is none. All five say the same three things in slightly different words: treat the symptoms the person actually has, consider calling Poison Help or a medical toxicologist, and expect to watch the person for a while because the drug lingers.

The Wegovy label is the only one that describes what an overdose looks like, and it borrows that description from reports on other drugs in the class: “severe nausea, severe vomiting, and severe hypoglycemia.”^[4] Ozempic and Rybelsus give the same advice without the symptom list.^[3][5] The two tirzepatide labels drop the word “prolonged,” reflecting a half-life closer to five days, and the Zepbound label goes furthest, telling you to contact Poison Help rather than to consider it.^[6][7]

The half-life is why an overdose is different from a bad week on a normal dose. After an injection, the amount of drug in the body falls by half roughly every seven days for semaglutide and five for tirzepatide. So half of an accidental extra dose of semaglutide is still in the body a week later, and a quarter two weeks later. How long ordinary side effects tend to last is covered in how long GLP-1 side effects last.

How overdoses happen: FDA's warning on compounded vials

Brand pens are hard to overdose on by accident: they are built to deliver set doses in milligrams, at a standard concentration.^[1] Compounded semaglutide and tirzepatide usually arrive in a multi-dose vial with a box of insulin syringes, and the dose has to be measured by hand. That is where FDA found the problem.

On 26 July 2024 the agency warned health care providers, compounders and patients that it had received reports of adverse events, some needing hospital care, linked to dosing errors with compounded injectable semaglutide.^[1] In most of the reports, patients drew more than their prescribed dose from a multi-dose vial and injected five to 20 times the intended amount.^[1] Clinicians made errors too: several miscalculated the conversion from milligrams to units or milliliters, producing doses five to ten times too high.^[1]

• Units are not milligrams. Patients told to inject 5 units (0.05 mL) with a 1 mL U-100 syringe injected 50 units instead.^[1]
• Concentration varies. FDA said strength “may vary depending on the compounder,” and one compounder may sell several.^[1] The same number of units therefore delivers a different dose from a different vial.
• Wrong-size syringes. Some patients were given syringes far larger than the volume they needed.^[1]
• Prescribing slips. One provider meant 0.25 mg (5 units) and wrote 25 units; the patient got five times the dose and had severe vomiting. Another wrote 20 units instead of 2, and three patients received ten times their dose.^[1]
• No one to ask. One patient could not get clear instructions from the telehealth prescriber, searched online, and took five times the intended dose.^[1]

The effects in those reports were nausea, vomiting, abdominal pain, fainting, headache, migraine, dehydration, acute pancreatitis and gallstones.^[1] FDA has since widened its warning. Its page on unapproved GLP-1 drugs, last updated in October 2026, now covers compounded tirzepatide as well, and adds reports of patients prescribed compounded doses above what the approved labels allow, taken more often or increased faster than the label schedule.^[2] As of 31 May 2026 FDA had 990 adverse event reports of all kinds for compounded semaglutide and more than 730 for compounded tirzepatide, and it expects the true numbers are higher because most compounding pharmacies are not required to report.^[2]

Poison centers saw the same pattern before FDA’s alert. A 2023 case series from one regional center described three people on compounded semaglutide bought through compounding pharmacies and a spa; two had injected ten times their dose, and symptoms lasted for days. One patient received a vial and syringes with no pharmacist counseling.^[11] A New York City Poison Control Center series described three accidental overdoses at the start of treatment, including 2 mg injected instead of 0.1 mg and 2.4 mg instead of 0.25 mg.^[12]

What poison center data show

The National Poison Data System records calls to all US poison centers. Three national analyses of it, all in the Journal of Medical Toxicology, tell a consistent story: calls about GLP-1 drugs have risen sharply since semaglutide was approved for weight loss, most involve dosing mistakes, and most people have mild effects.

The rate of reported cases more than quintupled from 2017 to 2022, from 1.16 to 6.32 per million US residents.^[8] By 2024 it had reached 18.79 per million, an increase of more than 1,800% from 2017.^[9] After semaglutide’s weight-loss approval in 2021, semaglutide calls grew by an extra 9.9% each quarter.^[10] America’s Poison Centers, the association of the 53 US centers, puts the rise in calls about injectable weight-loss drugs since 2019 at nearly 1,500%, a figure it publishes without a stated method.^[15]

Two cautions apply to these numbers. Calls count people who phoned, not everyone who made a mistake, and some calls are about side effects at normal doses. And the rise follows a huge increase in the number of people taking these drugs, so more calls do not by themselves mean each dose became more dangerous. What has changed is who is calling: younger people, more women, and a growing share referred to a hospital.^[10] Children 6 to 17 were more than twice as likely as adults to be admitted.^[9]

Symptoms of too much semaglutide or tirzepatide

An overdose usually looks like the normal side effects, turned up and stretched out. In 152 patients managed in emergency departments by three Florida poison centers, 92% of those with symptoms had nausea and 76% vomiting; most effects lasted 8 to 24 hours, and the usual treatment was intravenous fluids and anti-nausea medicine.^[14] In a separate Alabama poison center review, 67% of callers reported no symptoms at all and 62% were monitored at home.^[13]

• Severe nausea and repeated vomiting. The most common effect in every series.^[12][13][14]
• Abdominal pain, weakness, headache, fainting. Reported by FDA and in poison center cases.^[1][11]
• Dehydration. The labels warn that vomiting and diarrhea can dehydrate a person enough to injure the kidneys, in some reported cases badly enough to need dialysis.^[3][7]
• Low blood sugar. The risk is clearest with insulin or a sulfonylurea.^[3][7] It is less common without them, but not absent (see below).
• Pancreatitis or gallstones. Both appear in FDA’s overdose reports.^[1] Severe upper abdominal pain that spreads to the back needs urgent care; the background risk is covered in GLP-1 pancreatitis and gallbladder risk.

Does a GLP-1 overdose cause low blood sugar?

Sometimes. GLP-1 drugs raise insulin mainly when glucose is high, which is why the New York case series saw no hypoglycemia in its three overdoses.^[12] The Alabama review found it rare: two cases on a GLP-1 alone and two more with insulin.^[13] But the Florida study, which excluded anyone who had also taken a glucose-lowering drug, still found low blood sugar in 9% of patients.^[14] The Zepbound label adds that hypoglycemia has been seen in adults without diabetes on these drugs.^[7] Anyone who has overdosed should know the signs of low blood sugar, and people on insulin or a sulfonylurea should tell Poison Help straight away.

Who is most at risk

• People on compounded vials, measuring doses by hand in units, especially in the first weeks.^[1][2]
• People new to injecting. In the Alabama data, 21% of exposures were errors on first use of a pen.^[13]
• People on insulin or a sulfonylurea, for low blood sugar.^[3][7]
• Children and teenagers, who are admitted more often than adults after an exposure.^[9]
• Anyone who cannot keep fluids down, because of the dehydration and kidney risk.^[3][7]

How to avoid an overdose

Nearly every overdose in the published reports traces back to a measuring or prescribing mistake, so most are preventable.

• Read the concentration on your own vial. It is printed in mg/mL, and it decides how many units your dose is. The arithmetic and tables are in GLP-1 units to mg.
• Check your prescriber’s numbers. Convert their instruction yourself with the GLP-1 unit converter, or work backwards from the units you drew with the reverse dose calculator. If the answers disagree, ask before injecting.
• Learn your label. The vial label reader explains each field on a compounded vial label.
• Use a syringe sized for your dose. FDA urged prescribers and compounders to supply the appropriate syringe size and to show patients how to measure the dose with it.^[1]
• Re-check after any change: a new pharmacy, a new vial strength or a dose increase. Each one changes the units.^[1]
• Missed a dose? Do not double up. The missed dose guide sets out each label’s rule.

Why compounded products carry these extra risks, and what you give up with them, is set out in compounded vs brand semaglutide and what is in a compounded GLP-1 vial. FDA asks patients and clinicians to report dosing errors through its MedWatch program.^[1]