Jabwise

Diarrhoea on a GLP-1

Mounjaro’s, Wegovy’s and Ozempic’s leaflets list diarrhoea as very common, more than 1 in 10 people, and both NHS pages list it. In two Zepbound trials, 19% to 23% reported it, against 8% on placebo. Wegovy’s and Ozempic’s leaflets say it can cause dehydration, and that drinking fluids is important to prevent it.

Placebo: 8 in 10015mg: 23 in 100

Reported diarrhoea in Zepbound’s trials

How common it is

Each leaflet’s own words for how common diarrhoea is, quoted as written. Zepbound’s label counts it among its most common side effects.

MedicineHow common
MounjaroVery common (may affect more than 1 in 10 people)Mounjaro KwikPen patient leaflet
ZepboundThe most common adverse reactions, reported in ≥5% of patients treated with ZEPBOUND are: nausea, diarrheaZepbound prescribing information
WegovyVery common: may affect more than 1 in 10 peopleWegovy FlexTouch patient leaflet
OzempicVery common (may affect more than 1 in 10 people)Ozempic patient leaflet

What else they say

  • It usually eases

    Wegovy’s and Ozempic’s leaflets say diarrhoea usually goes away over time; Mounjaro’s says it decreases in most patients.

  • By dose in the trials

    In Zepbound’s trials, diarrhoea was reported by 19% on 5mg, 21% on 10mg and 23% on 15mg, against 8% on placebo.

  • Losing fluids

    Mounjaro’s leaflet says losing fluids at the start may reduce kidney function, and to avoid dehydration with plenty of fluids.

  • If it bothers you

    If a side effect bothers you or doesn’t go away, the NHS says a pharmacist or doctor may give advice on how to reduce it.

Questions

Is diarrhoea a side effect of Mounjaro?

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

How long does it last?

None of the sources gives a timescale. Wegovy’s and Ozempic’s leaflets say it usually goes away over time; Zepbound’s label says most cases in its trials came while the dose was going up.

When should I get help?

The NHS says call 111 if you think you’re having a serious side effect. Zepbound’s label asks you to tell your healthcare provider right away if diarrhoea doesn’t go away.

Side effects

Count the days it’s there.

Each check-in asks “Any side effects currently?”, and Diarrhoea is one tap. Side Effects counts the days you felt it, over 7, 30 or 90 days, ready for your next review.

Jabwise Side Effects: constipation on 2 of 6 days with a check-in, over the last 7 days

Sources

General information, not medical advice. Follow your prescriber’s guidance.

Getting real advice

We’re not doctors. This page sums up what the NHS and the official medicine information say, and can’t tell you what’s right for your body: your prescriber’s instructions and the leaflet in your box come first. More in our terms.

  • Quoted from official sources, each one linked
  • Sources checked 12 October 2026
  • No dosing advice; your prescriber comes first