Peptide · Fact sheet
Linaclotide
Also known as Linzess · guanylate cyclase-C agonist
Linaclotide is FDA approved as Linzess for specific forms of constipation and constipation-predominant irritable bowel syndrome in defined adult and pediatric age groups. It is not a systemic recovery, metabolic, or gut-healing peptide.
What is Linaclotide?
Linaclotide is a 14-amino-acid peptide that activates guanylate cyclase-C on the intestinal surface and is minimally absorbed into the bloodstream.
Its local action increases intestinal fluid and can change pain signaling, which is why evidence is tied to constipation outcomes.
Benefits people look for
It demonstrates that an oral peptide can work primarily at the gut surface without needing broad systemic exposure.
The same secretory mechanism that helps constipation also explains the main risk: diarrhea and dehydration.
What the evidence supports
- Phase 3 trials found improvements in bowel-frequency and abdominal-symptom endpoints compared with placebo.
- Pediatric trials supported selected age-specific label expansions rather than unrestricted use in children.
All research areas
- IBS with constipation
- Chronic idiopathic constipation
- Pediatric functional constipation
- Abdominal pain and bowel symptoms
- Other carefully defined disorders of gut sensation and motility
Anecdotal reports & lived experiences
Reports describe what someone noticed. They cannot establish cause, typical results, or how often a side effect happens.
No attributable personal reports are summarized here yet. The benefits above describe research interests; the side effects below come from the cited medical sources.
We do not fill this gap with unsourced testimonials or estimated success rates.
Side effects & risks
- The label carries a boxed warning about serious dehydration risk in children younger than 2 years.
- Severe diarrhea can occur and is the main clinically important adverse effect.
- It is contraindicated when mechanical gastrointestinal obstruction is known or suspected.
This is a summary of the cited evidence, not a complete product label. A lack of human safety data does not establish safety.
Clinical research: how strong is it?
Strong human evidence for approved usesMultiple controlled trials and indication expansions support the labeled gastrointestinal uses. The peptide's local action and evidence do not establish general microbiome, anti-inflammatory, or wellness benefits.
Selected research to read
Controlled trial of abdominal pain and bowel outcomes with randomized withdrawal.
Age-specific Phase 3 evidence supporting a pediatric indication.
FDA approval & research status
Current FDA labeling covers IBS with constipation, chronic idiopathic constipation, and pediatric functional constipation in the specific age groups listed for each indication.
Approved uses covered here
- The adult and age-specific pediatric constipation indications in current Linzess labeling
FDA approved for labeled constipation disorders
Linaclotide is approved under the Linzess label for specific adult and pediatric constipation-related indications. The approval is label-specific.
This summarizes the cited product or research record. Trial phases do not establish successful completion of earlier stages, and a stopped program is not ongoing development. Approval applies only to the labeled product, use and population.
What we still don’t know
- Which patients will have a durable response rather than intolerable diarrhea
- Long-term comparative effectiveness across approved constipation medicines
- Whether other formulations can separate pain relief from secretory effects
- Benefits outside labeled constipation disorders
The takeaway
Linaclotide is a well-studied local gut peptide for specific constipation disorders. It should not be stretched into a general claim about repairing or optimizing the gut.
Sources & further reading
Medical evidence and regulatory sources are listed here. Personal reports are linked separately in the experiences section.
- 1fdaFDA prescribing information: Linzess
Current age-specific indications, boxed warning, contraindications, and safety information.
- 2pubmedRandomized Phase 3 IBS-C trial
Controlled trial of abdominal pain and bowel outcomes with randomized withdrawal.
- 3pubmedRandomized pediatric functional-constipation trial
Age-specific Phase 3 evidence supporting a pediatric indication.