# Feeling sick on a GLP-1

> Mounjaro’s, Wegovy’s and Ozempic’s leaflets list feeling sick as very common, more than 1 in 10 people, and both NHS pages list it. In two Zepbound trials, 25% to 29% reported nausea, against 8% on placebo. Mounjaro’s leaflet says it’s most common when first starting, and decreases over time in most patients.

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

## How common it is

Each leaflet’s own words for how common it is, quoted as written. Zepbound’s figures are the share of people in its two weight trials who reported it.

- **Mounjaro**: Feeling sick: "Very common (may affect more than 1 in 10 people)" ([Mounjaro KwikPen patient leaflet](https://www.medicines.org.uk/emc/product/15481/pil)); Being sick: Very common for weight management; common in adults treated for type 2 diabetes
- **Zepbound**: Feeling sick: 25% to 29%, against 8% on placebo; Being sick: 8% to 13%, against 2% on placebo
- **Wegovy**: Feeling sick: "Very common: may affect more than 1 in 10 people" ([Wegovy FlexTouch patient leaflet](https://www.medicines.org.uk/emc/product/13800/pil)); Being sick: "Very common: may affect more than 1 in 10 people" ([Wegovy FlexTouch patient leaflet](https://www.medicines.org.uk/emc/product/13800/pil))
- **Ozempic**: Feeling sick: "Very common (may affect more than 1 in 10 people)" ([Ozempic patient leaflet](https://www.medicines.org.uk/emc/product/9748/pil)); Being sick: "Common (may affect up to 1 in 10 people)" ([Ozempic patient leaflet](https://www.medicines.org.uk/emc/product/9748/pil))

## What else they say

- **Most common at the start**: Mounjaro’s leaflet says feeling sick is usually not severe, most common at first, and decreases over time in most patients.
- **While the dose goes up**: Zepbound’s label says most nausea, vomiting and diarrhoea in its trials came while the dose was going up, then decreased.
- **Fluids**: Wegovy’s and Ozempic’s leaflets say being sick can cause dehydration, and that drinking fluids is important to prevent it.
- **Stopping for gut side effects**: In two Zepbound trials, 1.9% to 4.3% stopped treatment due to stomach and gut side effects, against 0.5% on placebo.

## Questions

### Is nausea a side effect of Mounjaro?

Yes. Mounjaro’s leaflet lists feeling sick as very common, more than 1 in 10 people, and says it’s usually not severe and decreases over time in most patients.

### Does alcohol make it worse?

Both NHS pages say alcohol can increase side effects like feeling or being sick. The semaglutide page says it’s best not to drink it; the tirzepatide page, best to avoid it.

### When is it serious?

Mounjaro’s, Wegovy’s and Ozempic’s leaflets say stop using it and seek urgent medical help for severe, persistent stomach pain, with or without nausea and vomiting, as it could be pancreatitis.

## In Jabwise: Patterns

See where it falls in your jab week. Tap Nausea or Vomiting in a check-in. After 8 regular jab weeks, After Your Jab counts the days you felt each, and names a day of your jab week if one stands out.

## 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/)