Diarrhea on a GLP-1: 30 percent on Wegovy and 23 percent on Zepbound
Diarrhea reached 30 percent on Wegovy 2.4 mg and 23 percent on Zepbound 15 mg in the clinical trials printed on their FDA labels, against 16 and 8 percent on placebo. GLP Chart read both labels on DailyMed, revised June and August 2026.
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| Label and dose | Who was in the trial | On the drug | On placebo |
|---|---|---|---|
| Wegovy 2.4 mg (June 2026 label) | adults with obesity or overweight, n=2,116 | 30% | 16% (n=1,261) |
| Zepbound 5 mg (August 2026 label) | adults with obesity or overweight, n=630 | 19% | 8% (n=958) |
| Zepbound 10 mg (August 2026 label) | adults with obesity or overweight, n=948 | 21% | 8% (n=958) |
| Zepbound 15 mg (August 2026 label) | adults with obesity or overweight, n=941 | 23% | 8% (n=958) |
| Ozempic 0.5 mg (June 2026 label) | adults with type 2 diabetes, n=260 | 8.5% | 1.9% (n=262) |
| Ozempic 1 mg (June 2026 label) | adults with type 2 diabetes, n=261 | 8.8% | 1.9% (n=262) |
| Mounjaro 5 mg (August 2026 label) | adults with type 2 diabetes, n=237 | 12% | 9% (n=235) |
| Mounjaro 10 mg (August 2026 label) | adults with type 2 diabetes, n=240 | 13% | 9% (n=235) |
| Mounjaro 15 mg (August 2026 label) | adults with type 2 diabetes, n=241 | 17% | 9% (n=235) |
Half of that 30 percent is not the drug
16 percent of the Wegovy placebo arm reported diarrhea. So the drug accounts for a 14 point gap, not the full 30. Nausea on the same label is a 28 point gap.
Print 30 percent on its own and the reader concludes the drug did all of it. The label prints both columns.
The dose step, where the label prints one
Tirzepatide climbs. Zepbound reads 19 percent at 5 mg, 21 percent at 10 mg and 23 percent at 15 mg. Mounjaro reads 12 percent at 5 mg and 17 percent at 15 mg. Semaglutide barely moves: Ozempic is 8.5 percent at 0.5 mg and 8.8 percent at 1 mg.
The Wegovy table that compares 2.4 mg with 7.2 mg has no diarrhea row. The label does not answer that question, so neither do we.
What a slower ladder costs
Neither label says what the slower route costs. On some programs the lower dose is the cheaper one and on others the price does not move at all.
| Drug | Cheapest program we track | At the maintenance dose | At the top dose it publishes |
|---|---|---|---|
| Wegovy | Knownwell | $299 a month | Publishes one figure only |
| Zepbound | Sam's Club Member Health | $399 a month | $449 a month, with refills inside 45 days |
LifeMD charges $200 a month more at the top of its ladder than at the dose you stay on. Ask the program what it charges at each dose before you agree to climb.
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What the labels tell a prescriber
- Zepbound's label says what its diarrhea row counts:
The label counts diarrhea and frequent bowel movements in this row.
Zepbound label, section 6.1 - No label in this set names an anti-diarrheal.Wegovy, Zepbound, Ozempic and Mounjaro labels
- In the pooled STEP 1 to 3 trials, 99.5 percent of the gut reactions on semaglutide 2.4 mg were non-serious.Wharton 2022, DOI 10.1111/dom.14551
- Neither weight-management label prints an instruction aimed at diarrhea. The two dose sentences the weight-management labels carry are general. Wegovy's reads:
If patients do not tolerate a dose during dosage escalation, consider delaying dosage escalation for 4 weeks.
Zepbound's reads:If patients do not tolerate a maintenance dosage, consider a lower maintenance dosage.
Wegovy label, section 2 and Zepbound label, section 2
How long it lasts
Zepbound's label puts it this way: The majority of nausea, vomiting, and/or diarrhea events occurred during dose escalation and decreased over time.
Mounjaro's label carries the same sentence, and Ozempic's carries the escalation half of it. In SURMOUNT-1 those reactions came mostly inside the 20 week escalation period. Neither document published a day count.Zepbound, Ozempic and Mounjaro labels, section 6.1; Jastreboff 2022, DOI 10.1056/NEJMoa2206038
What a dose change costs
Both weight-management labels answer a tolerability problem the same way, by slowing the ladder or stepping back down. What that does to the bill depends on the program. Shed lists $199 a month, the same figure at every dose. Strut Health lists $149 a month, with auto-refill. Medvi lists $299 a month, after $179 for the first month. None of the three sets its price by the dose, so holding a step costs the same as taking it.
Frequently asked questions
How common is diarrhea on a GLP-1?
Wegovy's label puts it at 30 percent at 2.4 mg against 16 percent on placebo. Zepbound's puts it at 19 percent at 5 mg, 21 percent at 10 mg and 23 percent at 15 mg, against 8 percent on placebo. It is the second most reported reaction on both labels after nausea.
Why does the placebo number matter so much here?
Because it is large. 16 percent of the Wegovy placebo arm reported diarrhea, so the gap between drug and placebo is 14 points, not 30. Nausea on the same label is a 28 point gap. Both arms of the trial were on a reduced-calorie diet.
Does a higher dose mean more of it?
On tirzepatide, yes. Zepbound climbs from 19 percent at 5 mg to 23 percent at 15 mg and Mounjaro from 12 percent to 17 percent. On semaglutide the move is small: Ozempic reads 8.5 percent at 0.5 mg and 8.8 percent at 1 mg. Wegovy's high-dose table has no diarrhea row at all, so the label does not answer the 2.4 mg against 7.2 mg question.
What is in the label's diarrhea row?
Zepbound's label says the row counts diarrhea and frequent bowel movements together. Wegovy's lists diarrhea on its own. The two figures are not a clean head to head.
Does the label say what to do?
Only through the dose. Wegovy's label says to consider delaying escalation by 4 weeks if a dose is not tolerated. Zepbound's says to consider a lower maintenance dosage. Both sentences are addressed to the prescriber. Persistent diarrhea with signs of dehydration is a same-day call to the prescriber.
Every dosage sentence on this page is written to a prescriber, not to you. Holding a dose, dropping back or stopping changes what the drug is doing. Take the label language to the appointment.
Sources
Evidence checked August 31, 2026
Every figure above is taken from the document beside it, the FDA label or the trial that produced it, so you can read the source instead of trusting us. No clinician reviews these pages. What that means.
- The 30 percent Wegovy figure, its 16 percent placebo column and the tolerability sentence about delaying escalationFDA prescribing information for Wegovy, injection and tablets (DailyMed, revised June 2026)
- The Zepbound rates at 5 mg, 10 mg and 15 mg, the note that the row counts frequent bowel movements as well as diarrhea, and the sentence about considering a lower maintenance dosageFDA prescribing information for Zepbound (DailyMed, revised August 2026)
- The Ozempic rates at 0.5 mg and 1 mg in adults with type 2 diabetesFDA prescribing information for Ozempic injection (DailyMed, revised June 2026)
- The Mounjaro rates at 5 mg, 10 mg and 15 mg in adults with type 2 diabetesFDA prescribing information for Mounjaro (DailyMed, revised August 2026)
- The share of gut reactions that were non-seriousWharton S et al. Diabetes Obes Metab 2022;24(1):94-105
- The dose-escalation period and the paper's own description of when the reactions cameJastreboff AM et al. N Engl J Med 2022;387(3):205-216