Semaglutide side effects, and how long they last
On this page
Week by week: when they start and when they peak
The week-by-week picture comes from an analysis of four trials of semaglutide 2.4 mg, called STEP 1 to 4. They’re the trials the WEGOVY label reports as Studies 2 to 5; both list the same ClinicalTrials.gov numbers. The drug was started at 0.25 mg and stepped up every four weeks to 2.4 mg at week 16, the same climb as the label’s own schedule.3
| Weeks | Dose | What the trials saw |
|---|---|---|
| 1 to 16 | 0.25 to 1.7 mg | Most first episodes happen here. Constipation reaches a plateau by about week 10. |
| About 20 | 2.4 mg | Nausea, diarrhea and vomiting are at their most common. New first episodes level off. |
| 20 to 68 | 2.4 mg | All three become less common, nausea most of all, though they stay above placebo for the whole trial. |
Doses: WEGOVY prescribing information, Table 1 (label revised 6/2026). Timing: Wharton et al., Diabetes, Obesity and Metabolism 2022, pooled STEP 1–3 trials (2,117 people on semaglutide 2.4 mg, 1,262 on placebo, 68 weeks).
The WEGOVY label says the same thing in one line about its trials: “These reactions were most frequently reported during dosage escalation.” The OZEMPIC label, whose trials were in type 2 diabetes at lower doses, puts it this way:1,2
The majority of reports of nausea, vomiting, and/or diarrhea occurred during dose escalation.
So the stretch to plan around is the escalation itself, roughly the first five months. Where your own steps fall is on the semaglutide dosage chart.
How often each of these was reported is a separate question from how long it lasts, and each label answers it for its own product, in its own population: WEGOVY’s table is from weight trials at 2.4 mg, and OZEMPIC’s from diabetes trials at 0.5 mg and 1 mg. The rates are roughly twice as high on the first. Three of the four effects have a page of their own now: nausea, diarrhea and constipation.
How long one episode lasts
Days. Half of episodes were shorter than the figure shown and half longer.
Wharton et al., Diabetes, Obesity and Metabolism 2022, Results, pooled STEP 1–3 trials. The authors report the nausea, diarrhea and vomiting durations as similar to placebo.
The authors’ summary is that people “typically recovered from each event within a few days.” Constipation is the exception, lasting weeks rather than days, on placebo as well as on the drug.3
Almost all of these episodes were mild or moderate: 98.1% of the stomach side effects reported on semaglutide in STEP 1 to 3. More serious ones did happen, and the WEGOVY label counts severe stomach side effects in 4.1% of people on the injection against 0.9% on placebo.3,1
After the escalation: do they stop?
Mostly, for people who got through the first 20 weeks. STEP 4 followed the 803 people who reached 2.4 mg in its run-in to week 68, and the paper counts only two discontinuations for stomach side effects after week 20. Among those who stayed on the drug, nausea, diarrhea and constipation grew less common over time, and vomiting stayed low.3
It isn’t zero, and the paper says so. Stomach side effects stayed more common than on placebo for the whole 68 weeks, and the authors note that a small proportion of people may keep having them throughout treatment. They read the later excess as mostly repeat episodes in people who had already had one during the escalation.
What moves the timeline: holds and restarts
Pausing the climb is part of the label, not a failure of it. If a dose isn’t tolerated during escalation, the WEGOVY label tells the prescriber to consider waiting:
If patients do not tolerate a dose during dosage escalation, consider delaying dosage escalation for 4 weeks.
In the trials, stomach side effects led to a dose reduction or a temporary break for 12.5% of people on semaglutide, against 1.7% on placebo, and 74.0% of those people still finished the study on treatment. A four-week hold pushes every later step back by four weeks.3
A gap does the same thing in reverse. After two or more missed WEGOVY doses in a row, the label restarts the escalation at a lower dose, and the escalation weeks come back with it. If you missed a semaglutide dose quotes that instruction in full.1
When it’s more than the usual pattern
A bout that runs days and eases fits the trial pattern. The label names the ones that don’t, in the Medication Guide written for patients:
Tell your healthcare provider right away if you have nausea, vomiting, or diarrhea that does not go away.
Stop using WEGOVY and call your healthcare provider right away if you have severe pain in your stomach area (abdomen) that will not go away, with or without nausea or vomiting.
For the day-to-day side, nausea on semaglutide covers what people try in the days after a step up, and what to eat on semaglutide covers the food.
Questions
Do side effects mean it’s working?
Not in the trials. In STEP 1 to 3, people on semaglutide 2.4 mg lost 11.4% to 17.7% of their weight on average if they had stomach side effects and 9.6% to 17.1% if they didn’t. The authors found the side effects accounted for less than one percentage point of the extra weight lost compared with placebo.3
Will they come back when my dose goes up?
They may. The trials saw stomach side effects most often during and shortly after the escalation, peaking around week 20, just after the last step up to 2.4 mg. The WEGOVY label says they were most frequently reported during dosage escalation.
How long does constipation last on semaglutide?
Longer than the others. A constipation episode lasted a median of 47 days on semaglutide 2.4 mg in STEP 1 to 3, against 35 days on placebo, and how common it was leveled off at about week 10.3
Is it the same on OZEMPIC?
The timing is. The OZEMPIC label says the majority of reports of nausea, vomiting and diarrhea occurred during dose escalation. The day counts come from trials of the 2.4 mg dose, which is WEGOVY’s, so they aren’t OZEMPIC’s own figures.
A held step moves everything after it back, including when the weight comes off. What the WEGOVY trials measured at each stage covers that side of the same weeks.
Read next
Sources
A reference, not medical advice, and not a substitute for your prescriber or pharmacist. If you think you are having a medical emergency, call your local emergency number.