Constipation is one of the most common side effects of semaglutide. It is usually mild. It also tends to hang on longer than the nausea people expect.
Here is what the trials counted, why it happens, and what clinical guidance suggests. You will also see when it stops being a routine side effect.
How common is it?
The Wegovy label pools three trials of the 2.4 mg injection [1]. Constipation was reported by 24% on semaglutide and 11% on placebo.
| Drug and dose | Drug group | Placebo |
|---|---|---|
| Semaglutide 2.4 mg weekly | 24% | 11% |
| Tirzepatide 5 mg weekly | 17% | 5% |
| Tirzepatide 10 mg weekly | 14% | 5% |
| Tirzepatide 15 mg weekly | 11% | 5% |
The tirzepatide rows come from the Zepbound label’s own pooled trials [5]. The trials differ, so the two drugs’ rates are not a head-to-head result.
A pooled analysis of STEP 1 to 3 gave the same picture: 24.2% on semaglutide against 11.1% on placebo [2]. Across all stomach and bowel effects, 99.5% of events were not serious. The rest of the record is in semaglutide side effects.
Why it happens
Semaglutide slows how fast the stomach empties. The Wegovy label names that delay as a direct effect of the drug [1].
You also eat and often drink less. The consensus paper notes that feeling full can cut how much water people take in, which may add to it [3].
When it starts and how long it lasts
Most stomach and bowel side effects showed up during or soon after dose increases [2]. They were mostly mild to moderate and passed with time.
Constipation is the exception in one way. The consensus paper reports it can begin in the first 16 weeks, especially the first 28 days [3].
It also lasts longer than the other effects. In people with obesity on a GLP-1 drug, symptoms persisted for a median of 47 days, the paper reports.
What the guidance suggests
No trial has compared ways to treat constipation on semaglutide. What exists is expert guidance, and it starts with the basics.
The 2025 nutrition advisory calls constipation common with weight loss and says to manage it early [4]. It encourages enough fluids and fiber from food, raised gradually, such as prunes or other dried fruit.
It notes that high-protein and high-fat foods slow the stomach further. Limiting them for a while may help, it says.
If food changes are not enough, the advisory lists daily magnesium, fiber supplements, polyethylene glycol 3350 and stool softeners. The consensus paper adds more movement and more water [3].
The consensus paper says a prescriber may consider a lower dose if symptoms get worse [3]. The dose steps are covered in semaglutide dosage.
When it is more than routine
After approval, the Wegovy label lists reports of ileus, intestinal obstruction and severe constipation with fecal impaction [1]. These are voluntary reports, so their true rate is unknown.
Severe stomach and bowel reactions affected 4.1% on the injection and 0.9% on placebo in the weight trials. The label says Wegovy is not recommended in severe gastroparesis.
A 2025 meta-analysis pooled 55 placebo-controlled trials with 106,395 people [6]. It found GLP-1 drugs probably have little or no effect on intestinal obstruction or ileus. They did raise the risk of gallstones and reflux.
The consensus paper’s own last step is to tell your prescriber if symptoms persist despite everything above [3].
Related reading
Food choices on the drug are covered in what to eat on semaglutide. Eating habits that ease nausea are in the same food guide.
For tirzepatide, see tirzepatide side effects. Planning a pregnancy on the drug is covered in Ozempic and pregnancy.
To compare prescribers, see the compounded semaglutide rankings.