GLP-1 Constipation: What Causes It and How to Fix It
The complete guide to GLP-1 constipation — why it happens on Ozempic, Wegovy, Mounjaro, and Zepbound, and the fiber, magnesium, and hydration fixes that actually work.
Key takeaways
- Fiber + magnesium + hydration is the three-part fix that works for 90% of GLP-1 constipation.
- Soluble fiber (psyllium, acacia) works better than insoluble fiber on a GLP-1.
- Magnesium citrate at night is the fastest supplement-based fix.
- Aim for a bowel movement at least every 2 days; call your provider if 4+ days pass.
- Prunes, kiwi, and chia seeds are the best food-based fixes.
Constipation is the second-most common GLP-1 side effect after nausea and the one that quietly ruins quality of life. Slower digestion, less food volume, and lower fluid intake stack up fast.
The good news: constipation on a GLP-1 responds well to a simple three-part protocol. Here is how to fix it.
Why GLP-1s cause constipation
GLP-1s slow the entire GI tract, not just the stomach. Combine that with less food (less bulk), less water (less lubrication), and less fiber (less stimulation) and constipation becomes the default.
The three-part fix
- Fiber — 5–10 g soluble fiber daily (psyllium or acacia)
- Magnesium — 300–400 mg magnesium citrate or glycinate at night
- Water — 80+ oz daily plus one electrolyte serving
Foods that help
- Prunes — 3–5 daily
- Kiwifruit — 2 per day is a clinically studied dose
- Chia seeds — 1–2 tablespoons soaked in water or yogurt
- Berries, pears, apples with skin
- Leafy greens and cruciferous vegetables
- Beans and lentils in small portions
When to escalate
If you have not had a bowel movement in 3+ days despite fiber, magnesium, and water, a short course of an osmotic laxative like MiraLAX (polyethylene glycol) is safe for most adults. Clear it with your prescriber first. If constipation is severe, causes vomiting, or lasts more than a week, call your provider.
Frequently asked questions
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