Typical durations
In the pooled STEP 1 to 3 analysis of semaglutide 2.4 mg, the median episode lasted:[1]
| Side effect | Median episode |
|---|---|
| Nausea | 8 days |
| Vomiting | 2 days |
| Diarrhea | 3 days |
| Constipation | 47 days (35 on placebo) |
A median means half of episodes were shorter and half were longer. A person can also have more than one episode, often one per dose step.[1]
When they come
- Weeks 1 to 20: dose build-up Most first episodes of nausea, vomiting and diarrhea happened during escalation, and their prevalence peaked around week 20, when escalation ends.[1]
- After week 20 New cases flattened off. Constipation plateaued earlier, around week 10.[1][2]
- Tirzepatide The Zepbound label and the pooled SURMOUNT analysis report the same pattern: most gut events during escalation, decreasing over time.[3][4]
How bad they get
98.1% of gut side effects in the semaglutide trials were rated mild or moderate, and 99.5% were not serious; severe events were 4.1% versus 0.9% on placebo.[1] Stopping because of them was 4.3% versus 0.7%.[1] Other side effects, such as hair loss, follow their own timelines and are covered on their own pages.
Heard vs evidence
The short version
Short on the way. A 35-second captioned version of this page is in production for the Fewer Bites channel. It will be embedded here when it is live.
Questions to bring to your prescriber
Print these or screenshot them. They are conversation starters, not a checklist of things to do.
- If a dose step is rough, is slowing the build-up an option for me?
- How long should a side effect last before I call you?
- Which side effects should I never wait out?
Education, not advice. This page explains what trials, labels and guidelines report. It does not tell anyone to start, change or stop a medicine. Your prescriber knows your history; this page does not.
Sources
- Wharton S et al. Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg: post hoc analysis of STEP 1–3. Diabetes Obes Metab 2022;24:94–105. primary read · post hoc · industry-funded
- Fewer Bites nausea dossier, section 3.2 (onset, escalation timing and duration). secondary · dossier summary of primary sources
- Eli Lilly / FDA. Zepbound (tirzepatide) prescribing information, revised 08/2026. label
- Rubino DM et al. Gastrointestinal tolerability of tirzepatide: post hoc analysis of SURMOUNT-1 to -4. Diabetes Obes Metab 2025;27:1826–35. primary read · post hoc · industry-funded