Constipation across the three product documents
All three sets of Saxenda® product information list constipation for adults. [1][2][3] The US and Canadian figures come from the same five placebo-controlled adult trials of 32 to 56 weeks, and every participant was also counselled on diet and activity. [1][3]
| Document and group | Saxenda® | Placebo | Note |
|---|---|---|---|
| US label, Table 2, adults [1] | 19.4% | 8.5% | Third most common adult reaction |
| Canadian monograph, Table 3, adults [3] | 658 of 3,384 (19.4%) | 165 of 1,941 (8.5%) | Same adult pool |
| US label, Table 3, ages 12–17 [1] | 4.8% | 2.4% | About six of 125 teens |
| EU SmPC, Table 4 [2] | Very common (≥1 in 10) | — | Leaflet: usually goes away in days or weeks |
| Post-approval reports [1][2][3] | Severe constipation, impaction, ileus, obstruction | — | No frequency; cause not established |
Reading the adult and teen numbers
The teen figure is about a quarter of the adult one, but it comes from a single trial of 125 young people, so it describes that trial rather than a rule about age. [1] What the two tables share is the ratio: in each, constipation was about twice as frequent on liraglutide as on placebo. [1]
Constipation was not among the leading reasons people stopped the medicine. In adults those were nausea, vomiting and diarrhea; in teenagers, vomiting and nausea. [1] Across all stomach and bowel complaints, 67.9% of adults on Saxenda® reported at least one, against 39.3% on placebo. [3]
What studies add for liraglutide
A 2025 systematic review and network meta-analysis pooled 39 studies with 33,354 adults who had overweight or obesity but no diabetes. Nausea, vomiting, diarrhea and constipation were the most common digestive effects, and liraglutide and semaglutide were the medicines associated with a higher constipation risk than placebo. [4]
In a 12-week Danish trial of 52 adults that stepped liraglutide up to 3 mg, nausea and constipation were the most frequently reported adverse events. [5]
For the rare serious end, a 2025 meta-analysis combined trials, cohort and case-control studies. Overall, GLP-1 medicines were not linked with a clearly higher risk of bowel obstruction or ileus, and results varied widely between studies. In the liraglutide subgroup, however, the odds were about three times higher than in comparison groups. [6] Observational data like these can show an association but not prove cause, and the events remain uncommon.
How liraglutide may slow things down
Label level: liraglutide delays gastric emptying, and it lowers weight by reducing how much people eat rather than by burning more energy. [1] The label lists constipation but does not explain its mechanism.
Study level: the liraglutide 3 mg studies cited on this site measured how quickly the stomach empties, not how fast stool moves through the colon, so a direct effect on the large bowel is not shown in these sources. [5]
General level: the NIH digestive diseases institute lists eating less or differently, too little fibre, too little fluid or dehydration, and less physical activity among causes of constipation. [7] Eating smaller portions on Saxenda®, or losing fluid through vomiting or diarrhea, could therefore play a part.
Other reasons stools may slow
- Medicines and supplements the NIH lists: iron, antacids containing aluminium or calcium, opioid pain medicines, some antidepressants, calcium channel blockers, diuretics and seizure medicines. [7]
- Routine changes: travel, pregnancy, getting older, putting off going to the toilet, or changing medicines or diet. [7]
- Health conditions: irritable bowel syndrome, an underactive thyroid, diabetes, coeliac disease and pelvic floor problems. [7]
- Severe stomach slowing: the US label does not recommend Saxenda® for people with severe gastroparesis, and the EU summary advises against it in inflammatory bowel disease. [1][2]
What the health agencies suggest
MedlinePlus self-care guidance centres on habits: add fibre-rich foods gradually, because a sudden increase can cause bloating and gas; drink more water, especially alongside extra fibre; keep active through the week; do not skip meals; avoid heavily processed and fast foods; and go when you feel the urge rather than holding it. Some people find a regular time each day, often after a meal, helps. [8] Getting to know your usual pattern makes changes easier to spot. [8]
On products, MedlinePlus notes that stool softeners are sold in pharmacies and that laxatives should be used as a provider advises, not taken when you have severe belly pain, nausea or vomiting, and not used for more than a week without advice. [8] The MedlinePlus summary adds asking your provider whether any medicine you take may be contributing. [9] Saxenda® slows stomach emptying, so the US label asks for monitoring of medicines taken by mouth at the same time; tell your pharmacist you use it. [1]
The Medication Guide asks you to report stomach problems that are severe or do not go away, and the EU leaflet asks you to drink plenty of fluids to avoid dehydration early in treatment. [1][2]
Saxenda® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| Constant belly pain with vomiting, a swollen belly or being unable to pass wind or stool | Emergency care now; a possible blocked bowel | Emergency | EU leaflet [2]; NIDDK [7] |
| Severe belly pain that does not go away, sometimes reaching the back | Stop Saxenda® and seek medical help straight away | Emergency | Medication Guide [1] |
| Blood in the stool, bleeding from the rectum, fever or losing weight without trying | A doctor the same day | Today | NIDDK [7] |
| No bowel movement for three days, with bloating, belly pain or nausea | Your prescriber or GP | Today | MedlinePlus [8] |
| Constipation that is severe, does not ease with self-care or keeps returning | Your prescriber | At your next appointment | Medication Guide [1]; NIDDK [7] |
