Peptide library / Digestive & weight / Linaclotide
Linaclotide
A 14 amino acid peptide taken by mouth that acts only inside the gut for irritable bowel syndrome with constipation.
Effects studied or claimed
What it is used or promoted for, and where each effect has actually been seen
- Irritable bowel syndrome with constipationFDA approved
- Chronic idiopathic constipationFDA approved
How it is thought to work
Linaclotide activates guanylate cyclase-C on the lining of the intestine, which increases fluid secretion and speeds transit, and also reduces pain signals from the gut.
What the evidence shows
Phase 3 trials showed more patients had improvement in abdominal pain and bowel movements than with placebo. The peptide is barely absorbed into the bloodstream.
Safety and unknowns
Diarrhea is the most common effect. The label carries a boxed warning against use in children under 2 because of the risk of severe dehydration.
Regulatory status
FDA-approved as Linzess in 2012.
Regulatory status changes quickly. This entry was last reviewed on 27 October 2026. Confirm current status with the FDA before relying on it.
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General information, not medical advice. Do not buy or inject unregulated peptides.