# Low blood sugar on a GLP-1

> Mostly with diabetes and a sulfonylurea or insulin: the Mounjaro, Wegovy and Ozempic leaflets and Zepbound’s label each say that raises the risk, and your doctor may lower those doses. Signs listed include headache, sweating, hunger, confusion and a fast heartbeat. Wegovy’s and Ozempic’s say they may come on suddenly.

Canonical: https://jabwise.app/guides/low-blood-sugar. Sources checked 12 October 2026. General information, not medical advice: follow your prescriber.

## Who it’s most likely for

From each leaflet and Zepbound’s label, quoted as written. All four name the same two medicines that raise the risk: a sulfonylurea and insulin.

- **Mounjaro**: Who’s at risk: "you are using a sulphonylurea (another diabetes medicine) or insulin for your diabetes, as low blood sugar (hypoglycaemia) can occur." ([Mounjaro KwikPen patient leaflet](https://www.medicines.org.uk/emc/product/15481/pil)); What may change: "Your doctor may need to change your dose of these other medicines to reduce this risk." ([Mounjaro KwikPen patient leaflet](https://www.medicines.org.uk/emc/product/15481/pil))
- **Zepbound**: Who’s at risk: "Your risk for getting low blood sugar may be higher if you use ZEPBOUND with medicines that can cause low blood sugar, such as an insulin or sulfonylurea." ([Zepbound prescribing information](https://uspl.lilly.com/zepbound/zepbound.html)); What may change: "Reducing dose of insulin or insulin secretagogue may be necessary." ([Zepbound prescribing information](https://uspl.lilly.com/zepbound/zepbound.html))
- **Wegovy**: Who’s at risk: "If you have diabetes and are taking a sulfonylurea or an insulin with wegovy® the risk of getting low blood sugar levels (hypoglycaemia) might increase." ([Wegovy FlexTouch patient leaflet](https://www.medicines.org.uk/emc/product/13800/pil)); What may change: "Your doctor may reduce your dose of these medicines before you start using this medicine." ([Wegovy FlexTouch patient leaflet](https://www.medicines.org.uk/emc/product/13800/pil))
- **Ozempic**: Who’s at risk: "Combining a sulfonylurea or an insulin with this medicine might increase the risk of getting low blood sugar levels (hypoglycaemia)." ([Ozempic patient leaflet](https://www.medicines.org.uk/emc/product/9748/pil)); What may change: "Your doctor may reduce your dose of these medicines before you start using this medicine." ([Ozempic patient leaflet](https://www.medicines.org.uk/emc/product/9748/pil))

## The warning signs

Each source’s own list, quoted as written. Wegovy’s and Ozempic’s leaflets use the same words, and the two NHS pages list different signs.

- **Mounjaro**: Signs it lists: "Symptoms of low blood sugar may include headache, drowsiness, weakness, dizziness, feeling hungry, confusion, irritability, fast heartbeat and sweating." ([Mounjaro KwikPen patient leaflet](https://www.medicines.org.uk/emc/product/15481/pil))
- **Zepbound**: Signs it lists: "Signs and symptoms of low blood sugar may include: dizziness or light-headedness; sweating; confusion or drowsiness; headache; blurred vision; slurred speech; shakiness; fast heartbeat; anxiety, irritability, or mood changes; hunger; weakness; feeling jittery" ([Zepbound prescribing information](https://uspl.lilly.com/zepbound/zepbound.html))
- **Wegovy**: Signs it lists: "The warning signs of low blood sugar may come on suddenly. They can include: cold sweat, cool pale skin, headache, fast heartbeat, feeling sick (nausea) or very hungry, changes in vision, feeling sleepy or weak, feeling nervous, anxious or confused, difficulty concentrating or shaking." ([Wegovy FlexTouch patient leaflet](https://www.medicines.org.uk/emc/product/13800/pil))
- **Ozempic**: Signs it lists: "The warning signs of low blood sugar may come on suddenly. They can include: cold sweat, cool pale skin, headache, fast heartbeat, feeling sick (nausea) or very hungry, changes in vision, feeling sleepy or weak, feeling nervous, anxious or confused, difficulty concentrating or shaking." ([Ozempic patient leaflet](https://www.medicines.org.uk/emc/product/9748/pil))
- **NHS (tirzepatide)**: Signs it lists: "low blood sugar (more likely if used with other diabetes medicines), which can cause headaches, vision problems, feeling dizzy, weak or confused, a fast heartbeat or sweating" ([NHS: Tirzepatide](https://www.nhs.uk/medicines/tirzepatide/))
- **NHS (semaglutide)**: Signs it lists: "low blood sugar, which can cause sweating, shaking, heart palpitations and feeling dizzy (this is more likely if used with other diabetes medicines)" ([NHS: Semaglutide](https://www.nhs.uk/medicines/semaglutide/))

## What they say to do

- **Treatment plan**: Mounjaro’s leaflet says your doctor should tell you how to treat low blood sugar; Wegovy’s and Ozempic’s say they will.
- **Testing**: On a sulfonylurea or insulin, Mounjaro says test as your doctor instructs; Wegovy and Ozempic say they may ask you to.
- **Driving**: With any signs of low blood sugar, Mounjaro’s leaflet says avoid driving; Wegovy’s and Ozempic’s say do not drive.
- **Telling your doctor**: On insulin or a sulfonylurea, Zepbound’s label says report any signs of low blood sugar to your healthcare provider.

## Questions

### Can it happen without diabetes?

Wegovy’s leaflet lists low blood sugar in patients without diabetes as uncommon, affecting up to 1 in 100 people. Zepbound’s label says it has also been associated with Zepbound in adults without type 2 diabetes.

### How common is it with diabetes medicines?

Mounjaro’s and Ozempic’s leaflets list it as very common, more than 1 in 10 people, with a sulfonylurea or insulin, and common with some other diabetes medicines. Wegovy’s lists it as common, up to 1 in 10, in patients with diabetes.

### What should I do if I get the signs?

Wegovy’s and Ozempic’s leaflets say your doctor will tell you how to treat low blood sugar and what to do if you notice the signs. If you think you’re having serious side effects, the NHS says call 111.

## In Jabwise: Side effects

Jabwise keeps your side effects in one place. Each check-in asks “Any side effects currently?”, a tap per answer. Side Effects then counts the days you felt each one, over 7, 30 or 90 days, ready for your next review.

## Getting real advice

- **A pharmacist, your doctor or NHS 111**: If you’re not sure how to use your medicine, or a side effect bothers you or won’t go away. NHS 111 if you think you might be having serious side effects, or you’ve used too much. [NHS: Semaglutide](https://www.nhs.uk/medicines/semaglutide/), [NHS: Tirzepatide](https://www.nhs.uk/medicines/tirzepatide/), [NHS 111 online](https://111.nhs.uk/)
- **Report a side effect**: Anyone can, not only doctors. [Yellow Card (UK)](https://yellowcard.mhra.gov.uk/), [MedWatch (US)](https://www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program)

## Sources

- [Mounjaro KwikPen patient leaflet](https://www.medicines.org.uk/emc/product/15481/pil)
- [Zepbound prescribing information](https://uspl.lilly.com/zepbound/zepbound.html)
- [Wegovy FlexTouch patient leaflet](https://www.medicines.org.uk/emc/product/13800/pil)
- [Ozempic patient leaflet](https://www.medicines.org.uk/emc/product/9748/pil)
- [NHS: Tirzepatide](https://www.nhs.uk/medicines/tirzepatide/)
- [NHS: Semaglutide](https://www.nhs.uk/medicines/semaglutide/)