GLP-1 overdose: symptoms and what to do

A GLP-1 overdose usually happens by mistake: a dose drawn up wrong from a vial, two doses taken too close together, or a pen used the wrong way. The usual symptoms are severe nausea, vomiting and stomach pain, sometimes with dangerously low blood sugar, and because semaglutide and tirzepatide stay in the body for days, the symptoms can last. If it happens to you or someone you care for, call Poison Help at 1-800-222-1222.

What to do right now

1. Call Poison Help at 1-800-222-1222. Poison control experts answer 24/7, free of charge, for emergencies and non-emergencies, including questions about GLP-1 doses (America’s Poison Centers). The Wegovy, Ozempic, Zepbound and Mounjaro labels all point to this line in an overdose.
2. Call 911 for an emergency. Poison centers say to call 911 right away if someone has collapsed, had a seizure, has trouble breathing or can’t be woken (Poison Help).
3. Have the details ready. Keep the vial, pen or syringe. Know the dose you meant to take, the amount you took, the concentration on the vial label and when you injected.
4. Don’t take another dose until a clinician tells you to.
5. Watch for low blood sugar if you also take insulin or a sulfonylurea, which raise that risk (America’s Poison Centers).
6. Report it. The FDA asks patients and clinicians to report GLP-1 dosing errors to its MedWatch program.

To save the number in your phone, text POISON to 301-597-7137. If an overdose was on purpose, or you are thinking about harming yourself, call or text 988 to reach the Suicide and Crisis Lifeline.

Symptoms of a GLP-1 overdose

The Wegovy label says overdoses reported with other GLP-1 drugs caused severe nausea, severe vomiting and severe low blood sugar (hypoglycemia) (Wegovy label, rev. 06/2026). The Ozempic, Zepbound and Mounjaro labels don’t list overdose symptoms; they advise supportive care based on the symptoms a person has. Poison centers say overdose symptoms look like the usual side effects (nausea, vomiting, diarrhea, constipation and stomach pain) but last longer, and that severe cases can bring dehydration or low blood sugar.

In its reports of compounded semaglutide dosing errors, the FDA also lists fainting, headache, migraine, dehydration, acute pancreatitis and gallstones. Some patients needed medical care or a hospital stay (FDA, Jul 26, 2024).

The reason symptoms can drag on is half-life, the time the body takes to clear half a dose. Semaglutide’s is about 1 week and tirzepatide’s about 5 days, and the labels warn that a long period of observation and treatment may be needed (Ozempic label; Zepbound label).

What published cases show

Single cases can’t tell you how likely an outcome is, but they show the range:

How dosing errors happen

Poison centers say most of their GLP-1 calls are accidental dosing errors with FDA-approved drugs, such as taking doses too close together or a higher dose at once. With compounded products, callers report taking 10 times the recommended dose because of confusing measurement units on a syringe. From 2019 to 2025, US poison centers managed 22,966 GLP-1 exposure cases, and calls about overdoses or side effects of injectable weight-loss drugs rose nearly 1,500% since 2019 (America’s Poison Centers). An exposure call is not always a poisoning, and call counts rise with public awareness.

Compounded vials measured in units

FDA-approved semaglutide injections come in pens that are dosed in milligrams at standard strengths. Compounded semaglutide and tirzepatide are different. They are not Wegovy, Ozempic or Zepbound, and not generics of them; a compounding pharmacy prepares them, and they aren’t FDA-approved. They often come in multiple-dose vials, at strengths that vary between pharmacies, sometimes with instructions in “units” rather than milligrams.

The FDA’s 2024 alert describes what went wrong (FDA):

• Most reports involved patients drawing up more than the prescribed dose from a vial. They injected 5 to 20 times the intended dose, and most were unfamiliar with measuring a dose in a syringe.
• Several patients were told to draw 5 units (0.05 mL) with a U-100 insulin syringe and drew 50 units instead.
• Clinicians also miscalculated. One meant to prescribe 0.25 mg (5 units) and wrote 25 units; another wrote 20 units instead of 2, and 3 patients received 10 times their dose.
• One patient couldn’t get clear instructions from the telehealth prescriber, searched online and took 5 times the intended dose.

The FDA has since received reports of compounded semaglutide or tirzepatide prescribed beyond the label’s doses: more per dose, more often, or with faster dose increases (FDA, updated Oct 1, 2026). As of May 31, 2026, it had 990 adverse event reports for compounded semaglutide and more than 730 for compounded tirzepatide. Those totals cover every kind of event, and the FDA notes that many pharmacies aren’t required to report, so the true number is likely higher.

A study of the FDA’s adverse event database from 2018 to 2024 found 707 reports for compounded products among 81,078 GLP-1 reports. Compounded products had higher reporting odds for preparation and prescribing errors, but lower odds for administration and dosing errors than brand products (McCall et al., 2026). Errors happen with both.

Brand pens and vials

Brand products can be misused too. The Zepbound KwikPen holds 4 fixed doses, and its instructions say not to count clicks as you select a dose. Zepbound vials need a syringe that can measure a 0.5 mL or 0.6 mL dose, with a new syringe and needle each time (Zepbound label). Our guide to injecting Zepbound walks through each form.

How to avoid a dosing mistake

• Know your dose three ways. Ask your prescriber or pharmacy for the dose in milligrams, the vial’s strength in mg per mL, and the volume or units to draw, and ask for a syringe sized for that dose. The FDA urges both steps for compounded vials.
• Double-check before you leave the pharmacy and before every injection (America’s Poison Centers).
• Set a reminder for the next dose, and don’t inject until it goes off.
• Follow the missed-dose rules on your label. Zepbound: take a missed dose within 4 days, and never take 2 doses within 3 days of each other. Wegovy: take it if the next dose is more than 2 days away; if you miss 2 or more doses in a row, the label restarts you at a lower dose. Ozempic: take it within 5 days.
• Throw out multiple-dose vials 28 days after first use and use a new needle and syringe for every dose, as the FDA advises.
• Buy only from state-licensed pharmacies or FDA-registered outsourcing facilities, never from unregulated online marketplaces.

If you would rather use a pen with a preset dose, our list of programs that prescribe brand-name GLP-1s orders the ones we list by our published rating method.

The bottom line

Most GLP-1 overdoses are accidents: doses taken too close together or too large with brand products, and unit mix-ups with compounded vials. Expect severe nausea, vomiting and stomach pain, watch for low blood sugar, and know that symptoms can last days because these drugs clear slowly. Call Poison Help at 1-800-222-1222 right away, call 911 for collapse, seizures, breathing trouble or someone who can’t be woken, and confirm your dose in milligrams and units before the next injection. At normal doses, every GLP-1 label in this guide leads with a boxed warning for thyroid C-cell tumors; our GLP-1 side effects guide covers that warning and the other label risks.