Clinical Trials

Numerous clinical trials sponsored by academic medical centers, including University Hospital Ghent, the University of Utah, and the University of Alberta, have evaluated 5-hydroxytryptophan across Phase 2 through Phase 4 studies. Completed research has investigated its efficacy in inflammatory bowel disease, mood regulation, and major depressive disorder as an antidepressant augmentation agent. Additionally, actively recruiting Phase 2/3 trials and related studies focus on its therapeutic potential in spinal cord injury, neuroendocrine tumors, cognitive changes, and tropical infections.

NCT Number Recruitment Conditions Sponsor/Collaborators Start Date Phases
NCT05895747 RECRUITING
Major Depressive Disorder
University of Utah
 2023-09-28 PHASE2
NCT07777328 RECRUITING
Attention Deficit and Hyperactivity Disorder (ADHD); Attention Deficit Hyperactivity Disorder in Adults; Attention Deficits
University of Sheffield
 2025-11-25
NCT06718452 NOT_YET_RECRUITING
Tinnitus; Neuroinflammation
University of Campania Luigi Vanvitelli
 2026-04-20
NCT04520178 RECRUITING
Spinal Cord Injuries
University of Alberta
 2020-07-01 PHASE2; PHASE3
NCT04160910 RECRUITING
Mild or Moderate Asthma With Allergic Sensitization
Indiana University
 2021-02-11 PHASE2
NCT04395183 COMPLETED
Major Depressive Disorder
University of Utah
 2021-03-01 PHASE2
NCT04000919 SUSPENDED
Spinal Cord Injuries
Jessica M D'Amico
 2019-06-19 PHASE2; PHASE3
NCT05030129 COMPLETED
Fragile X Syndrome
Elizabeth Berry-Kravis
 2021-10-07 PHASE2
NCT05543811 COMPLETED
Cognitive Change; Memory; Disturbance, Mild; Emotional Regulation; Concentration Ability Impaired
Federal State Budgetary Scientific Institution
 2022-09-15
NCT04078724 COMPLETED
Sleep; Gut Microbiome
National University of Singapore
 2020-07-04
NCT05216406 COMPLETED
Body Composition
Nova Southeastern University
 2021-01-01
NCT03574948 COMPLETED
Crohn Disease; Ulcerative Colitis; Fatigue; Remission
University Hospital, Ghent
 2018-12-06 PHASE2
NCT02922725 TERMINATED
Major Depressive Disorder
Brent Michael Kious, MD, PhD
 2016-11 PHASE4
NCT03574948 Completed
Crohn Disease|Ulcerative Colitis|Fatigue|Remission
University Hospital Ghent
 2018-12-06 Phase 2
NCT03112655 Completed
African Trypanosomiasis|African; Trypanosomiasis West|Sleeping Sickness; West African|Trypanosoma Brucei Gambiense; Infection
Institut de Recherche pour le Developpement|Institute of Tropical Medicine Belgium|Institut National de Recherche Biomédicale. Kinshasa République Démocratique du Congo|Ministry of Public Health Democratic Republic of the Congo
 2017-02-24 Not Applicable
NCT02815969 Completed
Neuroendocrine Tumors
University Medical Center Groningen
 2016-09 --
NCT02356107 COMPLETED
Major Depressive Disorder
Perry Renshaw
 2015-04 PHASE4
NCT02187341 UNKNOWN
Plasma Cortisol
Benedictine University
 2014-06
NCT02967354 COMPLETED
Type2 Diabetes
Per-Ola Carlsson
 2013-01
NCT02689479 COMPLETED
Type 1 Diabetes
National Institute of Allergy and Infectious Diseases (NIAID)
 2013-05
NCT01514409 COMPLETED
Mood
Northumbria University
 2011-05
NCT00227136 TERMINATED
Carcinoid Tumors; Neuroendocrine Tumors
University of Western Ontario, Canada
 2005-05 PHASE3
NCT00328913 COMPLETED
Obesity
TNO
 2006-03 PHASE2

(data from https://clinicaltrials.gov, updated on 2026-08-27)

Check the 5-hydroxytryptophan (5-HTP) product page for in-depth specifications, including solubility, stock solutions, MOA, and working concentrations.

Compliance for Clinical Use

Mechanism and Biochemical Profile

As a direct metabolic precursor, 5-hydroxytryptophan crosses the blood-brain barrier and undergoes decarboxylation by aromatic-L-amino-acid decarboxylase to increase serotonin synthesis and elevate central neurotransmitter bioavailability. This enhancement of central serotonergic signaling modulates downstream neurochemical pathways, providing a biological rationale for its clinical evaluation in major depressive disorder, mood dysregulation, and functional recovery from spinal cord injury.

Appendix RUO and cGMP Quality Standards

Quality Dimension RUO (Research Use Only) cGMP (Current Good Manufacturing Practice)
Clinical Applicability Prohibited in human clinical trials or medical diagnostics. Mandatory for human clinical trials (Phase I–III) and therapies.
Regulatory Status Non-regulated grade; exempt from drug manufacturing laws. Legally enforced by health authorities (e.g., FDA, EMA, NMPA).
Facility Environment Unclassified analytical or research laboratories. Validated Cleanrooms (ISO Class 5–8) with continuous monitoring.
Quality Control Basic purity and activity testing. Rigorous safety release testing (Sterility, Endotoxin, Mycoplasma).
Process Validation Basic equipment calibration; no process validation required. Full qualification (IQ/OQ/PQ) and complete batch records.
Quality Assurance Vendor self-declared without required formal QMS. Mandatory QA/QC unit, Change Control, CAPA, and vendor audits.
Regulatory Impact High risk of IND rejection if used as a critical raw material. Required for IND/NDA filings, supported by Drug Master Files (DMF).

Footnotes

Regulatory Note: Governed by FDA (21 CFR Parts 210/211/312), EMA (EudraLex Vol 4), ICH Guidelines (E6/Q7/Q9/Q10), and compendial standards (USP <71>/<85>/<1043>).

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Note: Technical data last updated: Sep 1, 2026.