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Immune

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Tight-junction modulator (gut)

Larazotide

Also known as: Larazotide acetate, AT-1001, INN-202, Gly-Gly-Val-Leu-Val-Gln-Pro-Gly

Furthest-developed clinical-stage peptide for celiac disease. The pivotal Phase 3 trials missed their primary endpoints; community marketing for general 'leaky gut' goes far past the evidence.

Reviewed 2026-05-05

What it does

Larazotide is a synthetic short peptide that targets the signaling pathway controlling intestinal tight junctions — the seals between cells in the gut lining. Its target indication is the roughly one-third of celiac patients on a strict gluten-free diet who continue to experience symptoms from inadvertent gluten exposure. Earlier mid-stage results were mildly encouraging. The pivotal Phase 3 trials, read out in 2022, did not meet their primary endpoints, and the program was wound down. Community and functional-medicine use for general 'leaky gut' or non-celiac gut permeability runs far past what the evidence supports — the trials were designed for active gluten exposure in celiac patients, not for a syndromic 'leaky gut' diagnosis.

Used for

Dose

Starting
500 mcg · 3× daily before meals
Common
1,250 mcg · 3× daily before meals
Upper
2,000 mcg · 3× daily before meals
When
Before activityTrials dosed at 0.5 mg, 15 minutes before meals. Time-of-day matters less than meal-relative timing — what's protected is the gluten-exposure window.
Site
oral

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⚠ Caution

  • Known hypersensitivity to larazotide
  • Pregnancy and breastfeeding (no human safety data outside clinical trials)
  • Pediatric use outside formal trials
  • Active GI malignancy (no data on tight-junction modulation in this context)

Your stack

Track this peptide in your protocol — dose, schedule, vials on hand, refill projection. Stays in your browser; no account needed.

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Use this peptide

Featured in protocols
  • Gut Healing — Phase 3 — Tight-junction layer (+Larazotide, optional)
Reconstitution & storage

Oral capsule formulation — no reconstitution. Taken approximately 15 minutes before meals.

Storage. Manufacturer instructions; typically room temperature, dry, protect from light.

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Monitoring & questions

Reported side effects
  • Generally well tolerated in trials — adverse-event profile similar to placebo
  • Headache
  • Upper-respiratory-tract symptoms
  • Urinary tract infection (modest excess vs placebo in Phase 2b)
  • Nausea
Biomarkers Juno tracks

Reference

How it works

Antagonizes zonulin signaling at the apical surface of intestinal epithelial cells. Zonulin (haptoglobin precursor 2) loosens tight junctions in response to gluten and certain bacteria; larazotide blocks this loosening, maintaining tight-junction integrity and reducing paracellular permeability. Active locally in the small intestine; minimal systemic absorption is expected given the route and design.

Juno's take

Larazotide is the most clinically-developed peptide in the gut-permeability space, and that's the story: a serious clinical program that worked encouragingly in mid-stage trials, then missed the bar in the pivotal trials. Real evidence for residual celiac symptoms; no evidence at all for the 'leaky gut' use case the community markets it for. We hold the line on that distinction. Anyone selling it as a general gut-healing tool is selling past what the science says.

EvidenceTier 2 — Human observational

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Symptom relief in celiac patients on gluten-free diet (residual symptoms)

Tier 2high confidence

Phase 2b trial (Leffler 2015, n=342) reported improved symptom scores at 0.5 mg TID. The pivotal Phase 3 CeDLara trial (n=525) did not meet its primary endpoint of celiac symptom-free days when read out in 2022, leading 9 Meters to wind down the program. Tier 2 reflects strong RCT-grade trials with mixed/null primary outcomes — better evidence than most peptides in this library, but not a positive Phase 3.

Leffler DA et al. 2015

Non-celiac 'leaky gut' / general intestinal permeability

Tier 4high confidence

Functional-medicine and community marketing extends larazotide use to non-celiac gut-permeability syndromes, IBS, and food-intolerance presentations. There is no RCT supporting any of these indications — the entire clinical development program targeted celiac.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Inflammatory and autoimmune conditions linked to gut permeability

Tier 4high confidence

The 'leaky gut as a driver of autoimmunity' hypothesis is mechanistically coherent but underpowered as a therapeutic rationale. Some preclinical work in NOD mice and other models exists; no human RCT in non-celiac autoimmune disease.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Citations (1)
  1. [1]
    Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free diet: a randomized controlled trial
    Leffler DA, Kelly CP, Green PH, et al. · Gastroenterology · 2015 · PMID 26060847
    Phase 2b RCT (n=342) — best published evidence for larazotide in residual celiac symptoms. Anchor for Tier 2 indication.
    View source