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ForumsSide Effects & ManagementDiarrhea vs constipation on GLP-1 — anyone have experience? Page 3

Diarrhea vs constipation on GLP-1 — anyone have experience?

HPLC_Greg Sun, Jan 4, 2026 at 3:28 AM 21 replies 1,190 viewsPage 3 of 5
nick_SD_fit
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Jan 8, 2026 at 2:58 AM#11
Dr.PeteFamMed said:
Fiber trials in this population are thin, and most of what gets quoted is extrapolated from idiopathic constipation in people eating normally.

Thank you — that is the clearest version of this I have read, and I have read a lot of them. Sending this to two other people who asked me the same thing last week.

Last edited: Jan 8, 2026 at 4:58 AM
6 4SkepticalSean, Dr.CardioMD, EndoResFellow and 3 others
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carl_compliance
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Jan 10, 2026 at 5:00 PM#12

Clinical perspective, offered as context rather than as advice.

Gastroparesis symptoms with constipation: the delayed gastric emptying from GLP-1 agonists can cause early satiety, bloating, and feeling "full" for hours after a small meal.

Tips: eat your protein FIRST (most important macro), then vegetables, then carbs last. Chew thoroughly — 20-30 chews per bite isn't excessive. Avoid carbonated beverages with meals. If symptoms are severe, your doctor may recommend a gastric emptying study.

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CarlaRPh_TPA
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Jan 13, 2026 at 7:00 AM#13
DeniseRN_TPA said:
Drug interaction alert relevant to constipation: if you take oral levothyroxine (Synthroid), GLP-1 agonists can reduce absorption due to delayed…

Heartburn management on constipation: Pepcid (famotidine) 20mg 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.

Last edited: Jan 13, 2026 at 11:00 AM
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Dr.RaviCardio
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Jan 15, 2026 at 8:59 PM#14
HPLC_Greg said:
The mechanism is slowed transit plus reduced intake, and that combination determines which interventions work.

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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mike_mod
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Jan 18, 2026 at 10:57 AM#15

Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful. Report rather than reply if it drifts again.

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