L-tryptophan supplementation for celiac disease symptoms

Restoration of Impaired Microbiota-mediated Aryl Hydrocarbon Receptor Signaling in Celiac Disease by Oral Tryptophan Supplementation: an Exploratory, Pilot Trial

Not applicable Interventional McMaster University · NCT05576038

This study is testing if taking L-tryptophan can help people with celiac disease who still have symptoms after a year on a gluten-free diet feel better.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment50 (estimated)
Ages18 Years to 75 Years
SexAll
SponsorMcMaster University Academic / other
Locations1 site (Hamilton, Ontario)
Trial IDNCT05576038 on ClinicalTrials.gov

What this trial studies

This trial evaluates the effects of L-tryptophan supplementation on individuals with biopsy-confirmed celiac disease who continue to experience symptoms despite following a gluten-free diet for over a year. Fifty participants aged 18 to 75 will be randomly assigned to receive either L-tryptophan or a placebo for three weeks. Participants will also receive dietary counseling to maintain a low tryptophan, gluten-free diet, and their compliance will be monitored through dietary recalls. The study will assess symptom changes and collect various biological samples to understand the impact of the intervention.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 to 75 with biopsy-confirmed celiac disease and persistent symptoms despite a gluten-free diet.

Not a fit: Patients with concurrent gastrointestinal diseases or those on certain medications may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a new dietary intervention for patients with celiac disease who do not respond to a gluten-free diet.

How similar studies have performed: While the approach of using L-tryptophan supplementation is novel, similar dietary interventions have shown promise in other gastrointestinal conditions.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion criteria:

* 18 and 75 years of age
* Celiac disease (CeD) diagnosis: Individuals with histological and serological evidence of CeD serology (positive biopsy and anti-tTG IgA)
* Persistent CeD related symptoms (\>40 on the Celiac Symptom Index) despite \>1 year of a gluten free diet (GFD)

Exclusion criteria:

* Acid anti-secretory and antacid medications
* Antibiotics, antibacterial agents or probiotics, currently, or within the last 8 weeks
* Current organic gastrointestinal or other autoimmune diseases, such as inflammatory bowel disease or diabetes mellitus (type 1)
* Lactose and/or fructose intolerance
* History of bariatric surgery, fundoplication or gastrectomy (partial or complete)
* Connective tissue disease
* Concurrent organic GI pathology other than benign polyps, haemorrhoids, lipomas, Helicobacter pylori infection, diverticulosis and melanosis coli
* Chronic treatment with high dose opioids
* Alcohol or drug abuse
* Concurrent systemic disease and/or laboratory abnormalities considered by investigators to be a risk or that could interfere with data collection
* Allergy or sensitivity to any component of the study medication or placebo
* Use of lithium and monoamine oxidase inhibitors (MAOIs)
* Participation in another dietary treatment study within the last 4 weeks

Where this trial is running

Hamilton, Ontario

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Tryptophan Metabolism AlterationsCeliac DiseaseTryptophanCeliac diseaseAryl Hydrocarbon Receptor
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.