Constipation on Ozempic: Causes and Practical Fixes

Constipation doesn't get talked about as much as nausea, but for a lot of people on Ozempic or other GLP-1 medications, it's the side effect that sticks around the longest. Estimates vary, but constipation affects up to roughly 30% of Ozempic users (Doctronic, 2026) — and unlike nausea, it tends to improve slowly and incompletely rather than resolving within a few weeks (LifeOnGLP, 2026).

Why it happens: two mechanisms working together

Slowed gastrointestinal motility. Semaglutide slows gastric emptying by an estimated 50–70% compared to baseline, and that slowdown extends beyond the stomach to the rest of the digestive tract (Doctronic, 2026). As waste spends longer in the colon, more water gets reabsorbed from it, leaving stool harder and more difficult to pass (Shield Medical Group, 2026; Sesame Care, 2026).

Reduced food and fluid intake. Because appetite drops, people naturally eat and drink less — and both fibre and fluid intake typically fall as a direct result. Since fibre adds bulk to stool and fluid keeps it soft, reduced intake of both compounds the mechanical slowdown already happening (GoodRx, 2026; Mochi Health, 2024).

Notably, fibre can also aggravate other GLP-1 side effects like gassiness and bloating in the short term, which can make people avoid it — precisely the food group that would actually help (GoodRx, 2026).

How common it actually is, and why it varies

Reported constipation rates vary quite a bit depending on the study and the dose. In diabetes-focused clinical trials, a relatively small percentage of participants reported constipation, but the side effect appears more prevalent among people using semaglutide for weight management at higher doses (Shield Medical Group, 2026). Higher doses of semaglutide have specifically been linked to a greater likelihood of gastrointestinal side effects generally (Shield Medical Group, 2026).

Constipation is also mechanistically distinct from other common GLP-1 side effects. It tends to last longer than nausea or diarrhoea, and doesn't resolve as reliably without active management (LifeOnGLP, 2026).

What actually helps: the evidence-backed strategies

Increase soluble fibre — gradually. Aim for roughly 25–35 grams of fibre daily from sources like psyllium husk, oats, beans, and fruit (Doctronic, 2026). Soluble fibre absorbs water and forms a gel-like substance that softens stool and promotes regularity (Doctronic, 2026). Increase intake gradually rather than all at once, since a sudden large increase can itself cause bloating and gas (Mochi Health, 2024).

Prioritise hydration. Adequate fluid intake becomes more important, not less, on a GLP-1 — the slowed transit gives your colon more time to draw water out of your stool, so replacing that fluid matters (Doctronic, 2026). General fluid guidance suggests roughly 9 cups (72 oz) daily for women and 13 cups (104 oz) for men, adjusted upward for exercise or heat (Sesame Care, 2026).

Prunes specifically have evidence behind them. Dried prunes or prune juice have been shown to help with constipation specifically, beyond their fibre content alone (Mochi Health, 2024).

Stay consistently active. Regular movement stimulates intestinal motility and has been shown to help relieve constipation, independent of dietary changes (Mochi Health, 2024).

Over-the-counter options exist if lifestyle measures aren't enough. Osmotic laxatives and stool softeners are commonly recommended as an additional step, alongside — not instead of — hydration and fibre (LifeOnGLP, 2026; GoodRx, 2026).

When it's more than a manageable side effect

If constipation is severe, persistent, or significantly affecting quality of life after four to six weeks of proactive management, it's worth a conversation with your prescriber about whether a dose adjustment makes sense (LifeOnGLP, 2026). This is a recognised clinical management tool, not a sign of failure — gastrointestinal side effects led to dose reduction or a temporary pause in treatment for 12.5% of semaglutide participants in the STEP trials (LifeOnGLP, 2026). Seek medical attention if constipation is accompanied by severe pain, vomiting, or rectal bleeding, or if you have a history of gastroparesis, slow gut motility, or bowel surgery that your prescriber should already be aware of (Doctronic, 2026; LifeOnGLP, 2026).

Why constipation management and nutrition are the same problem

The advice above only works if you're actually eating enough to get the fibre in — and that's exactly where GLP-1 constipation becomes a nutrition problem, not just a digestive one. If appetite suppression means you're eating too little overall, hitting 25–35 grams of fibre daily is genuinely difficult, regardless of how much you know you should.

This is exactly the kind of practical gap our While You're On It programme is built to close — structured nutrition support that accounts for reduced appetite, so fibre and fluid targets are realistic rather than theoretical.

If getting enough through food alone is a struggle, our Alongside Daily Support powder is formulated to help fill nutritional gaps when appetite is low.

Looking further ahead, our Coming Off It programme covers the tapering and maintenance phase, for when digestive side effects and everything else around treatment need a plan for winding down safely.

And if constipation isn't responding to the standard approach after a few weeks, our 1:1 coaching can help you troubleshoot alongside your prescriber.

The bottom line

Constipation on Ozempic comes from slowed gut motility combined with reduced food and fluid intake — a genuine, well-understood mechanical cause rather than bad luck. It tends to last longer than nausea and respond more slowly to management, but soluble fibre, consistent hydration, movement, and — when needed — osmotic laxatives are all backed by clinical guidance as effective steps. Persistent or severe constipation after weeks of proactive management is a legitimate reason to talk to your prescriber about your dose.

This article is for general information and isn't a substitute for medical advice. Contact your prescriber if constipation is severe, persistent, or accompanied by significant pain, vomiting, or rectal bleeding.

References

Doctronic. (2026, July 24). Ozempic and constipation: Why it happens and what helps. https://www.doctronic.ai/blog/ozempic-and-constipation/

GoodRx. (2026, April 2). Ozempic can cause constipation: Here's how to get relief. https://www.goodrx.com/ozempic/constipation

LifeOnGLP. (2026, March 24). Ozempic and constipation: Why it happens and how to fix it. https://lifeonglp.com/ozempic-and-constipation-why-it-happens-and-how-to-fix-it/

Mochi Health. (2024, August 28). Can Ozempic® cause constipation? https://joinmochi.com/blog/can-ozempic-cause-constipation

Sesame Care. (2026, July 22). Semaglutide (Ozempic and Wegovy) constipation: Causes and treatment options for relief. https://sesamecare.com/blog/ozempic-constipation

Shield Medical Group. (2026, April 2). Ozempic constipation: Causes & relief tips. https://shieldmedicalgroup.com/ozempic-and-your-gut-constipation-causes-and-remedies/