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Effect of Oral 5-HTP Intake on Urinary 5-HIAA Excretion

Phase 3
18 Years
Not Enrolling
Carcinoid Tumors, Neuroendocrine Tumors

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Trial Information

Effect of Oral 5-HTP Intake on Urinary 5-HIAA Excretion

5-HTP is a common over the counter product that is sold in natural food stores and via the
Internet. It is claimed to improve sleep problems, depression, anxiety, compulsive
disorders, restless leg syndrome, migraines, fibromyalgia, and low pain threshold.Increased
levels of 5-HIAA in the urine can be a of a specific type of cancer, called carcinoid tumor.
Urinary 5-HIAA levels can also be increased by a number of food products and drugs. Oral
5-HTP is not known as a cause of elevation of 5-HIAA in urine. However, recent information
suggests that 5-HTP may cause an increase.

In this study we examine the effect of oral 5-HTP intake (100 mg at bedtime for 10 days) on
5-HIAA excretion in the urine, following a prospective, double-blind placebo-controlled
study design.

Understanding this effect may help to determine which tests should be done in a patient with
increased 5-HIAA excretion who’s also taking 5-HTP.

Inclusion Criteria:

- 18 years and older

- in good health

Exclusion Criteria:

- Pregnancy

- Intake of drugs that affect 5-HIAA excretion in urine

- Anti-depressants

- Participation in other studies

Type of Study:


Study Design:

Allocation: Randomized, Endpoint Classification: Pharmacodynamics Study, Intervention Model: Crossover Assignment, Masking: Double-Blind, Primary Purpose: Diagnostic

Outcome Measure:

Urinary excretion of 5-HIAA

Principal Investigator

Stan HM Van Uum, MD, PhD

Investigator Role:

Principal Investigator

Investigator Affiliation:

University of Western Ontario, Canada


Canada: Health Canada

Study ID:




Start Date:

May 2005

Completion Date:

September 2005

Related Keywords:

  • Carcinoid Tumors
  • Neuroendocrine Tumors
  • 5Hydroxytryptamine
  • Chromogranin A
  • 5HIAA
  • carcinoid
  • Carcinoid Tumor
  • Neuroendocrine Tumors