Recovery ⏱ Half-life: 3-4 minutes (GI-localized, minimal systemic) FDA-Approved

Linaclotide

Linaclotide (Linzess/Constella)

Updated March 30, 2026

Evidence at a Glance

Regulatory statusFDA-Approved
FDA-approved 2012 as Linzess (Ironwood/AbbVie) for IBS-C and chronic idiopathic constipation; pediatric IBS-C added.
Human evidenceExtensive
Animal evidenceExtensive

Linaclotide is an FDA-approved oral guanylate cyclase-C agonist with large Phase 3 trials establishing efficacy for constipation-predominant IBS and chronic idiopathic constipation.

What the research does not support

  • It is not a weight-loss, muscle-recovery, or systemic performance peptide despite the catalog label; it acts locally in the gut.
  • It is minimally absorbed into the bloodstream, so it produces no hormonal or body-wide 'peptide therapy' effects.
  • It does not cure IBS; it manages constipation and abdominal symptoms only while being taken.
  • Diarrhea is its most common side effect, and it carries a boxed warning against use in young children.
Half-Life
3-4 minutes (GI-localized, minimal systemic)
Purity
Pharmaceutical grade
Mol. Weight
1,526.8 Da
Form
Oral capsules (72, 145, 290 mcg)

What is Linaclotide?

Linaclotide (Linzess) represents a novel approach to GI therapeutics — an oral peptide that works entirely within the gut without systemic absorption. It is one of the few peptides that can be administered orally by design, using the gut’s own receptor system to treat constipation-predominant IBS and chronic constipation.

Dosage Information (Research Use)

IBS-C: 290mcg orally once daily on an empty stomach, ≥30 minutes before first meal. CIC: 145mcg daily. Prescription medication.

Reconstitution & Handling

Oral capsule — no reconstitution.

Half-Life & Pharmacokinetics

3-4 minutes (GI-localized, minimal systemic)

Reported Observations in Literature

Diarrhea (20% — most common, may be severe in 2%), abdominal pain, flatulence, abdominal distension. Contraindicated in pediatric patients <2 years (risk of dehydration). Not a systemic drug — no significant systemic side effects.

Key Research References

  • Rao S et al. “A 12-week, randomized, controlled trial with a 4-week randomized withdrawal period to evaluate the efficacy and safety of linaclotide in IBS-C.” Am J Gastroenterol. 2012;107:1714-24

How Linaclotide Works

Linaclotide is a 14-amino acid peptide agonist of guanylate cyclase-C (GC-C) receptors on intestinal epithelial cells. Activation increases intracellular and extracellular cGMP, stimulating chloride and bicarbonate secretion into the intestinal lumen. This draws water into the gut, softening stool and accelerating transit. The extracellular cGMP also reduces visceral pain signaling, addressing both constipation and abdominal pain in IBS-C.

Research Applications

🔬 Irritable bowel syndrome with constipation
🔬 Chronic idiopathic constipation
🔬 Visceral pain modulation

Research Findings

Phase 3 trials showed significant improvements in both constipation (complete spontaneous bowel movements) and abdominal pain in IBS-C patients. Minimal systemic absorption — peptide is degraded in the GI tract, providing a localized mechanism. FDA-approved 2012.

Dosage & Administration

IBS-C: 290mcg orally once daily on an empty stomach, ≥30 minutes before first meal. CIC: 145mcg daily. Prescription medication.

Safety & Side Effects

Diarrhea (20% — most common, may be severe in 2%), abdominal pain, flatulence, abdominal distension. Contraindicated in pediatric patients <2 years (risk of dehydration). Not a systemic drug — no significant systemic side effects.

Important: All safety information is derived from published research, primarily animal studies. No controlled human clinical trial data exists unless explicitly noted. This compound is sold for research purposes only.

Quick Facts

Molecular Weight 1,526.8 Da
Half-Life 3-4 minutes (GI-localized, minimal systemic)
Purity Pharmaceutical grade
Form Oral capsules (72, 145, 290 mcg)
Storage Room temperature. Protect from moisture.

Key Research References

  • Rao S et al. "A 12-week, randomized, controlled trial with a 4-week randomized withdrawal period to evaluate the efficacy and safety of linaclotide in IBS-C." Am J Gastroenterol. 2012;107:1714-24

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