Encyclopedia of Clinical Neuropsychology

2018 Edition
| Editors: Jeffrey S. Kreutzer, John DeLuca, Bruce Caplan


  • Marla SanzoneEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-3-319-57111-9_1666


5-HTP; 5-hydroxytryptophan; Trp; Tryptophan; W

Indications and Definition

The term is sometimes used interchangeably with the term “tryptophan” and abbreviated “Trp” or “W.” l-Tryptophan is one of the nine essential amino acids available in most protein-based foods. Essential amino acids must be derived from food or supplements. Nonessential amino acids can be synthesized from essential or other nonessential amino acids. During digestion, l-tryptophan is broken down by intestinal bacteria that cause the odor associated with fecal material. The l-isomer from tryptophan contains the organic structural heterocyclic, indole, distinguishing it from tryptophan’s d-isomer. The l-isomer comprises the structure of the protein (IUPAC-IUB-JCBN 1983; l-Tryptophan 2009).

l-Tryptophan can be synthetically and organically derived. Synthetically, it is formulated from the bacterium, Escherichia coli, and the fermentation of serine, a nonessential organic polar amino acid, and indole....

This is a preview of subscription content, log in to check access.

References and Readings

  1. (IUPAC-IUB) (JCBN) International Union of Pure & Applied Chemistry & International Union of Biochemistry & Molecular (JCBN) Joint Commission on Biochemical Nomenclature. (1983). Nomenclature and symbolism for amino acids and peptides. In: Recommendations on organic and biochemical nomenclature, symbols and terminology. Retrieved February 3, 2009, from http://www.chem.qmul.ac.uk/iupac/AminoAcid.
  2. 5-Hydroxytryptophan. (2009). In Wikipedia. Retrieved February 3, 2009, from http://en.wikipedia.org/wiki/5-HTP.
  3. Fructose malabsorption. (2009). In Wikipedia. Retrieved February 3, 2009, from http://en.wikipedia.org/wiki/fructosemalabsorption.
  4. l-Tryptophan. (2009). In Wikipedia. Retrieved February 2, 2009, from http://en.wikipedia.org/wiki/Tryptophan.
  5. Metabolomics Toolbox. (2009). In Human metabolome database. Retrieved January 19, 2009, from http://hmdb.ca/scripts/show_card.cgi?METABOCARD=HMDB00216.txt.
  6. Monson, K., & Schoenstadt, A. (2008). In eMedTV. Retrieved February 2, 2009, from http://insomnia.emedtv.com/tryptophan/tryptophan-side-effects.html.
  7. Sandyk, R. (1992). l-tryptophan in neuro-psychiatric disorders: A review. International Journal of Neuroscience, 67, 24–144.Google Scholar
  8. South, J. (2009). l-Tryptophan, nature’s answer to Prozac. In Smart nutrition – International antiaging systems. Retrieved February 2, 2009, from http://www.smartnutrition.info/JamesSouth-tryptophan.htm.
  9. Tryptophan. (2003). In MedicineNet. Retrieved February 2, 2009, from http://www.medterms.com/tryptophan.
  10. Turner, E. H., Loftis, J. M., & Blackwell, A. D. (2006). Serotonin a la carte: Supplementation with the serotonin precursor 5-hydroxytryptophan. Pharmacology & Therapeutics, 109(3), 325–338.CrossRefGoogle Scholar
  11. Van Praag, H. M. (1983). In search of the action of antidepressants, 5HTP, tyrosine mixtures in depression. Neuropharmacology, 22, 433–440.PubMedCrossRefGoogle Scholar
  12. Vitamin B3. (2006). Vitamin B3 (niacin, nicotinic acid, nicotinamide) deficiency. In Vitamins & health supplements guide. Retrieved February 3, 2009, from http://www.vitamins-supplements.org/niacin-deficiency.php.

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Independent Practice, Loyola College of MarylandAnnapolisUSA