Larazotide
Larazotide Acetate (AT-1001)
Larazotide acetate (AT-1001) is a synthetic octapeptide derived from the Zonula occludens toxin of Vibrio cholerae, developed primarily for the treatment of celiac disease. It acts as a tight junction regulator to prevent gliadin-induced intestinal permeability, thereby reducing the immune activation triggered by gluten exposure. It has been investigated in Phase 2 and Phase 3 clinical trials as an adjunct to the gluten-free diet in celiac patients experiencing persistent symptoms.
Mechanism of Action
Larazotide antagonizes the action of zonulin, an endogenous protein that regulates tight junction permeability in the intestinal epithelium. By binding to tight junction-associated receptors and stabilizing occludin and claudin protein complexes, it prevents the paracellular passage of gluten-derived gliadin peptides across the gut epithelial barrier. This upstream blockade reduces lamina propria antigen presentation, thereby attenuating the downstream adaptive immune response, cytokine release, and intestinal inflammation characteristic of celiac disease.
Evidence by Health Goal(11 goals)
Dosing Protocols
Approximately 30 minutes before meals
0.5mg three times daily (1.5mg total daily dose) demonstrated the most favorable efficacy-to-safety ratio in Phase 2b trials. Higher doses of 1mg TID did not confer additional benefit and showed diminishing returns. Use in conjunction with a gluten-free diet, not as a replacement for dietary adherence.
Safety & Side Effects
Larazotide has demonstrated a generally favorable safety profile across multiple Phase 2 clinical trials with adverse event rates comparable to placebo; however, it is not yet FDA-approved and remains an investigational compound without long-term safety data beyond 12-week trial durations. It is not a prescription drug in most jurisdictions due to its investigational status, but sourcing outside clinical trials raises concerns about purity, peptide integrity, and lack of regulatory oversight.
Possible Side Effects
- !Headache (most commonly reported adverse event in clinical trials, ~14-18% of subjects)
- !Nausea, particularly when taken without adequate pre-meal timing
- !Abdominal discomfort or cramping
- !Diarrhea, typically mild and transient
- !Upper respiratory tract infection (reported at similar rates to placebo, likely not causally related)
- !Fatigue reported in a subset of trial participants
- !Rare hypersensitivity reactions including skin rash
Interactions
- -May theoretically reduce intestinal absorption of orally co-administered drugs if tight junction modulation affects paracellular transport dynamics — space administration from critical medications
- -Caution with other gut permeability-modifying agents (e.g., glutamine supplements, zinc carnosine) as combined effects on tight junction regulation are unstudied
- -No established pharmacokinetic interactions with immunosuppressants used in refractory celiac disease (e.g., budesonide, azathioprine), but concurrent use has not been rigorously studied
- -Probiotic supplementation may have additive or competing effects on intestinal barrier function; interaction magnitude is unknown
- -NSAIDs, which independently increase intestinal permeability, may blunt the therapeutic effect of larazotide
Cost & Where to Buy
Not commercially available as an approved pharmaceutical; cost reflects research-grade peptide sourcing from compounding or peptide vendors. Price varies significantly by vendor purity (HPLC-verified), lyophilization quality, and quantity purchased. Compounded oral capsule formulations may be available through specialty pharmacies at higher cost.
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