Nausea is the most common side effect of both semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound). On Wegovy 2.4 mg, 44% of adults in the weight-loss trials reported it, against 16% on placebo. On Zepbound it was 25% to 29% depending on dose, against 8%. This guide lays out what the FDA labels say about how often nausea happens at each dose, when it tends to happen, what the patient guides tell you to do, and when they say to call your doctor.
Everything here comes from the current prescribing information and a few trial papers, linked in the references. Where the labels say nothing, we say so.
These are the nausea rates from the label tables. The Wegovy and Zepbound numbers come from weight-loss trials. The Ozempic and Mounjaro numbers come from type 2 diabetes trials, which had different people and lower doses. The labels warn that rates from different drug trials "cannot be directly compared," so read across a row, not down the column.
| Label and trial pool | Placebo | Drug, by dose |
|---|---|---|
| Wegovy, adults, weight loss | 16% | 2.4 mg: 44% |
| Wegovy, adults, 7.2 mg trials | 13% | 2.4 mg: 35% · 7.2 mg: 39% |
| Wegovy, ages 12 and up | 18% | 2.4 mg: 42% |
| Ozempic, type 2 diabetes | 6.1% | 0.5 mg: 15.8% · 1 mg: 20.3% |
| Zepbound, adults, weight loss | 8% | 5 mg: 25% · 10 mg: 29% · 15 mg: 28% |
| Mounjaro, type 2 diabetes | 4% | 5 mg: 12% · 10 mg: 15% · 15 mg: 18% |
Sources: Wegovy label, 6.1, Tables 3 and 4 and the pediatric section; Ozempic label, 6.1, Table 1; Zepbound label, 6.1, Table 1; Mounjaro label, 6.1, Table 1.
Two things stand out. First, placebo groups report nausea too, sometimes a lot of it, so not every queasy day is the drug. Second, the tirzepatide weight-loss numbers barely move between 10 mg and 15 mg. The table does not show a simple "higher dose, more nausea" line for Zepbound.
On Wegovy, nausea was the most common side effect that led people to stop for good: 1.8% versus 0.2% on placebo (Wegovy label, 6.1).
The labels do not give a day-by-day or week-by-week nausea rate. What they do say is consistent across all four drugs: most nausea, vomiting and diarrhea happened while the dose was being raised.
The trial papers agree. A pooled look at the STEP 1 to 3 semaglutide trials found most GI events were mild to moderate, transient, and happened "most frequently during/shortly after dose escalation" (Wharton 2022). The STEP 1 paper described nausea and diarrhea as "typically transient and mild-to-moderate in severity" and said they "subsided with time" (Wilding 2021). For tirzepatide, the SURMOUNT-1 paper said GI events occurred "primarily during dose escalation" (Jastreboff 2022).
How long does it last? None of the labels give a number of days. "Transient" and "decreased over time" is as far as they go. For a phase-by-phase walk through the escalation schedule, see GLP-1 side effects week by week.
Not according to the trials. In the pooled STEP 1 to 3 data, weight loss on semaglutide 2.4 mg was similar in people without GI side effects (9.6% to 17.1%) and with them (11.4% to 17.7%). Of the extra weight lost versus placebo, less than 1 percentage point was explained by GI side effects (Wharton 2022). A similar analysis of SURMOUNT-1 to 4 found weight loss on tirzepatide was similar whether people reported no nausea, nausea alone or any nausea, vomiting or diarrhea, and that these symptoms accounted for up to 3.1% of total weight reduction (Rubino 2025). Both analyses list drug-maker employees among their authors.
So feeling sick is not a sign you need to feel sick. Not feeling sick does not mean the drug is failing.
Each drug comes with a Medication Guide, a plain-language part of the label written for patients. For nausea, the advice in the Wegovy, Ozempic, Zepbound and Mounjaro guides is short and nearly word for word the same:
The Wegovy and Zepbound guides add a separate line about severe stomach problems: tell your provider "if you have stomach problems that are severe or will not go away" (Wegovy Medication Guide; Zepbound Medication Guide).
What the guides do not include: food tips. We searched the full Wegovy, Ozempic, Zepbound and Mounjaro labels as published on DailyMed and found no advice about smaller meals, bland food or avoiding fatty food. You will see those tips on many websites, and your prescriber may suggest them, but they are not in the FDA labels.
This is the main reason the labels take nausea seriously. Each one has a warning called "Acute Kidney Injury Due to Volume Depletion" (Wegovy label, 5.5; Ozempic label, 5.6; Zepbound label, 5.3; Mounjaro label, 5.5). Volume depletion just means losing more fluid than you take in. The labels say:
The Wegovy label gives trial numbers too. In the adult weight-loss trials, sudden kidney injury happened in 7 people on Wegovy (0.4 cases per 100 patient-years) versus 4 on placebo (0.2). Some cases came with GI side effects or dehydration. The risk was higher in people who already had kidney problems, and it showed up more often while the dose was being raised (Wegovy label, 6.1).
The counseling section of the labels asks prescribers to tell patients to "take precautions to avoid fluid depletion" and to report "persistent (or extended) nausea, vomiting, and diarrhea" (Wegovy label, 17; Zepbound label, 17).
Only one label says so in plain words. The Wegovy label reads: "If patients do not tolerate a dose during dosage escalation, consider delaying dosage escalation for 4 weeks" (Wegovy label, 2.2). For people with the liver condition MASH, it also allows dropping from 2.4 mg to 1.7 mg if 2.4 mg is not tolerated, then trying 2.4 mg again later.
The others are less direct:
All four labels say the step-up schedule exists "to reduce the risk of gastrointestinal adverse reactions." Holding or lowering a dose is a call for your prescriber. Do not change it on your own.
One more timing rule: on Wegovy, if you miss 2 or more doses in a row, the label says to restart escalation at a lower dose, again to lower the risk of GI side effects (Wegovy label, 2.4). The Wegovy missed-dose guide and Zepbound missed-dose guide go through each label's rule.
The labels list a few situations where nausea comes with other symptoms that need a call right away:
The labels also say these drugs are not recommended for people with severe gastroparesis, a condition where the stomach empties very slowly (Wegovy label, 5.6; Zepbound label, 5.2).
Because the labels only say nausea is "mostly during escalation," a simple record of your own is worth bringing to appointments. Dose Track lets you log each dose, the injection site and any side effects on the same day, with reminders so doses are not missed. It also tracks pens, vials and supplies across all your compounds. Over a few step-ups, you can see whether nausea starts a day after the shot and fades, or keeps going. The guide to tracking GLP-1 doses and side effects covers what to write down.
This article is general information, not medical advice. Talk to your prescriber before you start, change or stop any medicine.