GLP-1 and Constipation: Why It Happens and How to Find Relief
Why GLP-1s Cause Constipation
GLP-1 medications work by slowing your gastric motility—essentially, they tell your stomach to empty more slowly. This is what creates the appetite suppression that helps you eat less and lose weight. But slower stomach emptying also means slower movement through your entire digestive tract. Food spends more time in your system, which leads to harder stools and less frequent bowel movements. It's a direct trade-off baked into how these medications work. The good news is that your body usually adapts within 4-6 weeks, and there are proven ways to manage it in the meantime.
Your First Line of Defense
Increasing soluble and insoluble fiber is the most effective natural remedy for GLP-1-related constipation. Fiber adds bulk to your stool and helps move things along. But here's the critical part: you have to drink enough water. Fiber without hydration can actually make constipation worse. Aim for 25-35 grams of fiber daily—fruits, vegetables, legumes, whole grains—but increase slowly over 1-2 weeks. A sudden jump to high fiber can cause bloating and cramping.
Drink at least 8-10 glasses of water daily, more if you're active or live in a hot climate. Many people on GLP-1s don't realize they're drinking less because they're eating less overall. Dehydration worsens constipation. A simple habit: drink a glass of water before and after each meal, plus with snacks.
Physical activity stimulates bowel movement. A 20-30 minute walk after meals, strength training, or gentle yoga can make a real difference. You don't need intense exercise—even light movement helps your digestive system do its job.
Over-the-Counter Options That Work
If fiber, water, and movement aren't enough, OTC medications can help:
1- Mag07 (Our Go-To Next Step)
For patients without kidney disease, Mag07 — an ozonated magnesium oxide supplement — is our favorite next-line option. The manufacturer recommends 3 capsules, but 2 is often enough. Mag07 is gentle enough to take on an ongoing basis, which makes it especially useful when you need regular maintenance rather than just occasional relief. (One important note: patients with chronic kidney disease should avoid magnesium-based laxatives. Your Shapely provider can help you pick a different option.)
2- Psyllium Husk
Psyllium (the fiber in Metamucil and similar products) is another effective option. It works by adding bulk and drawing water into your stool. Some patients get mild cramping with psyllium, especially when starting out, so begin with a smaller dose and increase gradually. Like all fiber, it only helps if you drink plenty of water with it.
3- Miralax
Miralax pulls water into your intestines, making stools softer and easier to pass. Mix one scoop in water daily. Most people feel relief within 2-3 days, and it’s gentle enough for longer-term use without causing dependency.
4- Senna
Senna is a stimulant laxative that’s been a constipation workhorse for decades. You may have read warnings online about long-term senna use causing dependency or damaging the bowel. The good news: rigorous reviews over the last twenty years have largely debunked these fears as medical myths. At standard therapeutic doses, chronic senna use appears to be safe. We think of senna as a reasonable option when osmotic laxatives like Miralax aren’t quite enough on their own, and it can be used on an ongoing basis if you and your Shapely provider find it works for you.
5- A Note on Docusate
Docusate (sometimes sold as Colace) is often recommended as a gentle stool softener, but in our experience it’s usually too mild to make a real dent in GLP-1-related constipation. We don’t typically lean on it.
Avoid These Common Mistakes
The biggest mistake we see is waiting too long. The good news is that constipation on GLP-1s is usually mild and tends to improve over time as your body adjusts — but it’s much easier to prevent than to fix once it sets in. Many patients do best on a regular daily bowel regimen (for example, Mag07 every evening) rather than reacting after things have already backed up. Severe constipation can also become bad enough to interfere with your ability to keep taking your GLP-1, so staying on top of it really matters. One other thing to skip: don’t assume high-dose fiber alone is the answer — without enough water, it can backfire.
When to See Your Provider
Constipation from GLP-1s usually resolves with the strategies above. But reach out to your Shapely provider if you experience severe abdominal pain (not just discomfort), you haven’t had a bowel movement in more than 3-4 days despite trying these interventions, you see blood in stool, or constipation persists beyond 6 weeks on medication. These could signal something else that needs attention. Your Shapely provider may also recommend stronger interventions when needed — a bottle of magnesium citrate (a single, strong dose used to clear things out) for severe constipation, or, in really stubborn cases, an enema. Both work, but they’re uncomfortable, which is exactly why catching constipation early matters. We can also adjust your GLP-1 dose or check for other underlying causes if your symptoms aren’t responding.
Final Thoughts
Constipation on GLP-1s is temporary and treatable. Your body is adjusting to slower digestion, but that adjustment period doesn't have to be miserable. Start with hydration and fiber, add movement, and use OTC stool softeners if needed. Most people find relief within 2-3 weeks with these approaches.
Remember: your provider wants you comfortable on this medication. If you're struggling, speak up. The goal is sustainable weight loss—and that only happens when you feel good enough to stick with it.