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ForumsSide Effects & ManagementDiarrhea vs constipation on GLP-1 — why different people get different GI effects Page 3

Diarrhea vs constipation on GLP-1 — why different people get different GI effects

Dr.GutHealth Mon, May 25, 2026 at 11:45 PM 15 replies 580 viewsPage 3 of 3
BiostatsBrad
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Jun 1, 2026 at 12:34 PM#11
jim_asheville said:
Fiber trials in this population are thin, and most of what gets quoted is extrapolated from idiopathic constipation in people eating normally.

Bookmarking. The distinction being drawn above is the one nobody else makes. Sending this to two other people who asked me the same thing last week.

26 24LindaRN_retired, tommy_boulder, hyun_seoul and 23 others
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jim_asheville
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Jun 2, 2026 at 4:08 AM#12

Clinical perspective, offered as context rather than as advice.

Heartburn management on constipation: Tums as needed has been my savior. The delayed gastric emptying means stomach acid just sits there.

Don't ignore persistent heartburn — chronic acid exposure can damage your esophagus. If OTC remedies aren't cutting it after 2 weeks, see your doctor for something stronger. You shouldn't suffer through this.

27 0BenResearch_OR, MikeKY_noInsulin, Dr.RaviCardio and 24 others
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LibrarianMeg
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Jun 2, 2026 at 7:42 PM#13
anders_CPH said:
Drug interaction alert relevant to constipation: if you take oral levothyroxine (Synthroid), GLP-1 agonists can reduce absorption due to delayed…

Gastric emptying studies and constipation: semaglutide delays gastric emptying by ~40% at steady state, as measured by acetaminophen absorption testing and scintigraphy[1].

Clinically relevant implications:

  • Explains early satiety and nausea
  • Affects absorption of co-administered oral medications
  • Creates aspiration risk for procedures under anesthesia
  • Contributes to constipation via slowed GI transit

Importantly, the gastric emptying delay attenuates with continued use (tachyphylaxis), which correlates with the transient nature of GI side effects.

References:
[1] Blundell J, et al. Diabetes Obes Metab. 2017;19(9):1242-1251.
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DataDave
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Jun 3, 2026 at 11:15 AM#14
Dr.GutHealth said:
The mechanism is slowed transit plus reduced intake, and that combination determines which interventions work.

Sulfur burps on constipation — the most underrated side effect nobody warned me about. 🤢 The smell is absolutely vile and comes on without warning.

What finally helped: Gas-X (simethicone) daily. Also, eating smaller portions and chewing thoroughly reduces the gas production.

If sulfur burps persist beyond 2-3 weeks, talk to your provider — it could indicate gastroparesis that needs medical attention.

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mike_mod
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Jun 4, 2026 at 2:48 AM#15

Moderator note: a post naming a supplier has been edited. Discuss suppliers in the review sections, not here. Report rather than reply if it drifts again.

Last edited: Jun 4, 2026 at 4:48 AM
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