Quick answer: a semaglutide overdose usually causes severe nausea, vomiting and belly pain, and can lead to dehydration or low blood sugar. Because semaglutide has a half-life of about 1 week, symptoms can last for days.[1] If you took too much Ozempic, Wegovy or compounded semaglutide, call Poison Help at 1-800-222-1222, or 911 for severe symptoms. The labels recommend supportive care and a longer period of monitoring.[2]
The labels do not list an antidote. Treatment focuses on managing symptoms, such as fluids and anti-nausea medicine, while the drug slowly clears. For background on the drug, see our semaglutide profile.
What counts as an overdose?
Anything above your prescribed dose, or doses closer together than prescribed, is too much. The label maximums are:
| Product | Maximum on the label |
|---|---|
| Ozempic injection | 2 mg once weekly[2] |
| Wegovy injection | 7.2 mg once weekly (adult weight reduction)[1] |
| Wegovy pill | 25 mg once daily; no more than one tablet a day[1] |
| Rybelsus / Ozempic tablets | 14 mg / 9 mg once daily; no more than one tablet a day[7] |
Branded pens make big mistakes harder because they only dial to fixed doses. The most common overdose route is drawing compounded semaglutide from a vial with a syringe.[3][5]
Symptoms of taking too much semaglutide
From the labels, FDA reports and poison center data, symptoms include:
- Stomach and gut: severe nausea, vomiting, belly pain and diarrhea, the most common problems.[1][3]
- Dehydration: dizziness, fainting, headache. The labels warn that fluid loss from vomiting or diarrhea can cause acute kidney injury.[1][3]
- Low blood sugar: shakiness, sweating, confusion. This is more likely if you also take insulin or a sulfonylurea.[1]
- Pancreatitis or gallstones: the FDA received overdose reports involving both.[3]
- Other: loss of appetite, weakness and fatigue.[5]
Compounded semaglutide dosing errors: units vs mg
In July 2024, the FDA warned about overdoses from compounded injectable semaglutide.[3] Compounded products often come in multi-dose vials. You draw your own dose with a syringe, often an insulin syringe marked in “units”. The FDA described two kinds of mistakes:
- Patients measuring wrong. Several patients were told to draw 5 units (0.05 mL) on a U-100 syringe and drew 50 units instead. Patients took 5 to 20 times their intended dose.
- Prescribers calculating wrong. In one report, a provider meant to prescribe 0.25 mg (5 units) but wrote 25 units. These errors led to 5 to 10 times the intended dose.
The core problem is that “units”, milliliters and milligrams are different measures:
| Measure | What it means |
|---|---|
| Milligrams (mg) | The amount of semaglutide, which is what your dose is |
| Milliliters (mL) | The volume of liquid |
| Units (U-100 syringe) | Syringe markings; 1 unit = 0.01 mL, so 100 units = 1 mL |
The number of milligrams in each unit depends on your vial’s concentration (mg per mL), and concentrations differ between compounders.[3] The same 0.25 mg dose can be a different number of units from one pharmacy to the next. The FDA asked prescribers and compounders to supply the right syringe size and teach patients how to measure.[3]
To understand syringe math in general, see our peptide calculator and our reconstitution guide. They don’t replace your prescriber’s exact instructions.
What the FDA has seen since
As of May 31, 2026, the FDA had received 990 adverse event reports involving compounded semaglutide. The agency notes that reports are likely underreported and don’t always prove the drug caused the problem.[4] It has also received reports of harm from doses above the label, larger single doses, more frequent dosing or faster increases.[4] For more on how compounded products differ, see compounded semaglutide vs Ozempic.
What poison center data show
- Poison center case series (2023): three people had adverse events after compounded semaglutide errors, two of them from 10-fold mistakes. All had nausea, vomiting and belly pain, mostly lasting days. One person who went to a clinic did well with an anti-nausea drug and IV fluids. One received a vial and syringes with no pharmacist counseling.[5]
- California, 2017-2023: 1,047 GLP-1 exposures were reported. Calls rose after Wegovy’s 2021 approval. 80% were unintentional dosing errors, two-thirds were managed at home, 21% were seen in an emergency department and 4.4% were admitted. Low blood sugar occurred in 3.8%. Of 36 cases involving compounded GLP-1s, 92% were administration errors.[6]
What to do if you took too much
- Call Poison Help (1-800-222-1222) or your prescriber right away, even if you feel fine. The labels name Poison Help or a medical toxicologist for overdose advice.[1][2]
- Have the details ready: product, concentration, how much you took and when, and your other medicines, especially insulin or sulfonylureas.
- Sip fluids if you can keep them down, and watch for the warning signs above.
- Check your blood sugar if you have diabetes and a meter.
- Don’t take your next dose until a clinician tells you how and when to restart. Restarting may need a lower dose.
- Report it to FDA MedWatch.[3]
Preventing a semaglutide overdose
- Know your dose in mg and in mL or units for your exact vial, and write both down.
- Use the syringe size your pharmacy supplies. Ask them to show you the mark.
- On an Ozempic pen, set the dose with the dose counter, not by counting clicks.[2]
- Take no more than one tablet a day of oral semaglutide.[7]
- If your pharmacy changes, or your vial’s concentration changes, recheck the mL or units for your dose before the next injection. The same milligram dose can mean a different number of units.[3]
- Keep a dose log. Our guide to missed GLP-1 doses covers what to do if you aren’t sure whether you already took this week’s shot.
How long symptoms last depends on how long the drug stays in you. See how long semaglutide stays in your system, and our semaglutide dosage chart for the label doses. More guides are on the semaglutide topic hub.
