Constipation in the product information
The US label and the Canadian monograph draw on the same two placebo-controlled trials, which the US label calls Trial 1 and Trial 6 and Canada calls PIONEER 1 and PIONEER 8 [1][3]. The US table only lists reactions seen in at least 5% of people on the tablets and more often than on placebo; Canada lowers that bar to 1% [1][3].
| Source | Placebo | 7 mg | 14 mg |
|---|---|---|---|
| US PI, Table 2 [1] | 2% | 6% | 5% |
| Canadian PM, Table 3 [3] | 2.5% | 5.9% | 5.3% |
| EU SmPC 4.8, ten phase 3a trials [2] | — | “Common” (1 in 100 to 1 in 10) | — |
| Bowel obstruction, ileus (all three) [1][2][3] | — | After approval only; frequency not known | — |
Lower strength, higher number
For nausea, stomach pain, diarrhoea, reduced appetite and vomiting, the 14 mg column is the highest. Constipation is the exception, at 6% on 7 mg and 5% on 14 mg [1]. Both are roughly two and a half to three times the placebo figure. With about 356 people per group, a one-point gap could easily be chance, so the safer reading is that constipation was more common on either strength than on placebo.
The label’s timing sentence names nausea, vomiting and diarrhoea, not constipation, as mostly reported while the dose was rising [1]. The Canadian leaflet likewise says nausea and diarrhoea usually fade with time but makes no such remark about constipation [3]. Neither tells you whether it shows up early or late, so only a dated personal record can show your own pattern.
When constipation becomes a blockage
The US label lists ileus, intestinal obstruction and severe constipation with faecal impaction among reactions reported voluntarily after semaglutide reached the market [1]. Canada names ileus among serious adverse reactions and warns that GLP-1 medicines may be linked to it [3]. Europe places intestinal obstruction in its “not known” column, because a frequency cannot be estimated [2].
Trial evidence points the other way. A 2025 meta-analysis of 55 placebo-controlled randomised trials with 106,395 participants found that GLP-1 medicines probably have little or no effect on intestinal obstruction, while raising the risk of gallstones [4]. Trials may still be too short to catch rare events.
Patient reports keep the topic visible. A 2024 study of FDA reports and online reviews for both forms of semaglutide counted 1,053 constipation reports in the database and 88 mentions in the reviews [5]. Neither source can give a rate or show cause [5].
Why semaglutide may slow the bowel
- From the label: part of how semaglutide lowers glucose is a minor delay in stomach emptying after meals [1]. The label stops at the stomach and does not link this to constipation.
- Plausible but not measured: Europe describes lower energy intake and reduced appetite as part of how semaglutide works [2], and NIH lists eating less fibre, drinking too little and changing how much and what you eat among causes of constipation [6]. No Rybelsus® study has tested this chain.
- Easy to overlook: NIH also names diabetes itself as a condition that can cause constipation [6], which is one reason the placebo group still reported it.
Other things that cause constipation
NIH lists many medicines and supplements that can make constipation worse, including antacids containing aluminium or calcium, iron supplements, narcotic pain medicines, some antidepressants, anticonvulsants, calcium channel blockers and diuretics [6]. Pregnancy, travel, ageing, ignoring the urge to go, an underactive thyroid, irritable bowel syndrome, coeliac disease and diverticular disease can all play a part [6]. If constipation began with another new medicine, mention both to your prescriber.
Self-care, fibre and laxatives around the tablet
MedlinePlus suggests regular exercise, more water, adding fibre slowly to avoid gas and bloating, not skipping meals, going when you feel the urge and trying a regular time each day [7]. It cautions against taking a laxative if you have severe stomach pain, nausea or vomiting, and against using one for more than a week without your provider’s advice [7].
Two tablet rules matter here. Rybelsus® is taken only with plain water, up to 4 ounces, and nothing else may be eaten, drunk or swallowed for 30 minutes; after that, you can eat and drink normally [1]. Semaglutide also slows stomach emptying, which can change how other oral medicines are absorbed [1]. So fibre powders, stool softeners and laxatives belong after the 30-minute wait, and your pharmacist or prescriber should know about them.
Rybelsus® and Ozempic® are registered trademarks of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.
When to get help
The signs and contact information below come from this article’s sourced guidance.
Emergency
- Constipation with constant belly pain, vomiting or being unable to pass gas
Contact: A doctor right away; emergency care if severe
- Severe stomach pain that does not go away, sometimes reaching the back
Contact: Stop Rybelsus® and call your provider right away
Rybelsus® Medication Guide [1]
Today
- Bleeding from the rectum, blood in the stool, fever, lower back pain or weight loss without trying
Contact: A doctor right away
NIDDK [6]
- No bowel movement for 3 days, or constipation with bloating, pain or nausea
Contact: Your provider
MedlinePlus [7]
- Severe or lingering stomach trouble of any kind
Contact: Your prescriber
Rybelsus® Medication Guide [1]
At your next appointment
- Constipation that self-care does not fix, or a family history of colon or rectal cancer
Contact: Your doctor at a planned visit
NIDDK [6]