Constipation on Wegovy® tablets

Tablet figures, and the one injection row

The tablet-specific number comes from OASIS 4, the US label’s Study 7: 204 adults without type 2 diabetes took the 25 mg tablet and 102 took placebo for up to 64 weeks. ^[1] The EU product information quotes the trial’s constipation rate and classes constipation as very common. ^[2] The ClinicalTrials.gov record shows the counts the sponsor entered; it is an official registry, not a peer-reviewed paper, and it lists non-serious events only when at least 5% of a group reported them. ^[3]

The US label instead refers the reader to Table 3, saying the tablet trial’s common reactions were similar in type and frequency. That table describes three trials of the 2.4 mg weekly injection, so its constipation row is an injection figure. ^[1]

Longer-lasting, and slightly ahead of diarrhea

The EU description of OASIS 4 sorts the digestive effects into two groups. Nausea, vomiting, indigestion, diarrhea and stomach pain were mostly mild to moderate and short. Constipation was also mild to moderate, but of longer duration. ^[2] The document gives no number of days, so how much longer is not stated. The EU leaflet still lists constipation among effects mainly seen during the dose climb that usually settle over time. ^[2]

On the tablet, constipation edged out diarrhea: 20.1% against 17.6%. In the injection trials behind the US Table 3 the order was the other way round, with diarrhea at 30% and constipation at 24%. ^[1][2] A second tablet trial, OASIS 1, which used 50 mg rather than the approved US tablet strength, showed constipation in 92 of 334 people on semaglutide (27.5%) and 50 of 333 on placebo (15.0%) over 75 weeks, again slightly above diarrhea. ^[4] These are separate trials, so the pattern is a description, not a rule.

Blockage, ileus and impacted stool

The serious end of the spectrum appears in two places. Section 6.2 of the US label lists ileus, intestinal obstruction and severe constipation including faecal impaction among problems reported during use of semaglutide after approval, and explains that such voluntary reports cannot give a frequency or establish cause. ^[1] The EU table lists intestinal obstruction, a grouped term that includes ileus, with the frequency “not known”, from the same kind of reports, and the EU leaflet describes bowel obstruction as a severe form of constipation with extra symptoms such as stomach ache, bloating and vomiting. ^[2]

In OASIS 4 itself, the registry’s full list of serious adverse events contains no bowel obstruction, ileus or constipation in either group. ^[3] A 2025 meta-analysis of 55 placebo-controlled trials with 106,395 participants, covering the whole GLP-1 class rather than this tablet, found that these medicines raised the risk of gallstones and probably reflux, but probably had little or no effect on intestinal obstruction, ileus and most other serious digestive events. ^[5] Trials of this size and length can miss very rare events, which is one reason the after-approval reports stay in the label.

MedlinePlus explains the difference: a mechanical obstruction is a physical block, for example from scar tissue, a hernia or impacted stool, while ileus is a bowel that stops moving without a structural cause. Symptoms include a swollen belly, cramping pain, nausea and vomiting, constipation and being unable to pass wind. ^[9]

What could slow the bowel on semaglutide

• What the label states: semaglutide slows stomach emptying and reduces how much people eat, an effect thought to work through appetite. ^[1] The label does not explain constipation itself.
• Plausible but not measured for the tablet: the NIDDK lists eating less or differently, too little fibre and too little fluid among common causes of constipation. ^[6] No source has shown how much of tablet constipation comes from these changes.
• What the timing suggests: the EU document places most digestive effects in the dose climb, yet describes constipation as the longest-lasting of them. ^[2]

Other things that cause constipation

Constipation often has more than one cause. The NIDDK lists medicines and supplements such as iron, antacids containing aluminium or calcium, opioid pain medicines, some antidepressants, diuretics, calcium channel blockers and anticonvulsants; life changes such as pregnancy, ageing and travel; and conditions including irritable bowel syndrome, diabetes, an underactive thyroid, pelvic floor problems and blockages from tumours. ^[6]

Ignoring the urge to go and a lack of physical activity also play a part. ^[6][8] If constipation started alongside a new supplement or another new medicine, that is worth mentioning, because the Wegovy® label asks you to tell your provider about everything you take. ^[1]

Self-care around a morning tablet

General guidance from the NIDDK and MedlinePlus is consistent: add fibre gradually, because a sudden increase can cause gas and bloating; drink plenty of fluids, especially with extra fibre; stay active; do not put off the urge; and try to go at the same time each day, often after a meal. ^[7][8] Over-the-counter laxatives are described as short-term options to discuss with a healthcare professional, with stimulant types kept for severe cases. MedlinePlus adds not to take a laxative if you have severe stomach pain, nausea or vomiting. ^[7][8]

The tablet changes the timing, not the advice. The label asks for nothing but the tablet and a little plain water first thing, then at least 30 minutes before food, other drinks or other oral medicines. ^[1] A fibre drink, a laxative or a stool softener therefore belongs after that window. The EU text adds that swallowing the tablet with several other tablets reduced semaglutide absorption, which is another reason to keep it alone. ^[2] A pharmacist can help you fit everything around the morning dose.

Wegovy® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.