You are using an unsupported browser. Please upgrade your browser to a newer version to get the best experience on Human Metabolome Database.
Record Information
Creation Date2005-11-16 15:48:42 UTC
Update Date2015-03-09 22:57:05 UTC
Secondary Accession Numbers
  • HMDB00504
Metabolite Identification
Common Name5-Hydroxy-L-tryptophan
Description5-Hydroxy-L-tryptophan is an aromatic amino acid naturally produced by the body from the essential amino acid l-tryptophan. 5-Hydroxy-L-tryptophan is the immediate precursor of the neurotransmitter serotonin. The conversion to serotonin is catalyzed by the enzyme aromatic l-amino acid decarboxylase (EC, AADC1 also known as dopa decarboxylase), an essential enzyme in the metabolism of the monoamine neurotransmitters. An accumulation of 5-Hydroxy-L-tryptophan in cerebrospinal fluid occurs in Aromatic l-amino acid decarboxylase deficiency (OMIM 608643 ), accompanied by an increased excretion in the urine of the patients, which are indicative of the disorder but not specific 5-Hydroxy-L-tryptophan is also increased in other disorders such as in Parkinson's patients with severe postural instability and gait disorders. Confirmation of the diagnosis AADC deficiency is then required by enzyme activity measurement or genetic analysis. The amount of endogenous 5-Hydroxy-L-tryptophan available for serotonin synthesis depends on the availability of tryptophan and on the activity of various enzymes, especially tryptophan hydroxylase (EC, indoleamine 2,3-dioxygenase (EC, and tryptophan 2,3-dioxygenase. (EC, TDO). 5-Hydroxy-L-tryptophan has been used clinically for over 30 years. In addition to depression, the therapeutic administration of 5-Hydroxy-L-tryptophan has been shown to be effective in treating a wide variety of conditions, including fibromyalgia, insomnia, binge eating associated with obesity, cerebellar ataxia, and chronic headaches. 5-Hydroxy-L-tryptophan easily crosses the blood-brain barrier and effectively increases central nervous system (CNS) synthesis of serotonin. Supplementation with 5-Hydroxy-L-tryptophan is hypothesized to normalize serotonin synthesis, which is putatively related to its antidepressant properties. (PMID: 9295177 , 17240182 , 16023217 ).
  1. (+-)-5-Hydroxytryptophan
  2. (S)-5-Hydroxytryptophan
  3. 5-Hydroxy-L-Tryptophan
  4. 5-Hydroxy-tryptophan
  5. 5-Hydroxyl-L-tryptophan
  6. 5-Hydroxytryptophan
  7. 5-Hydroxytryptophan L form
  8. 5-Hydroxytryptophan L-form
  9. Cincofarm
  10. Hydroxytryptophan
  11. L-5-Hydroxytryptophan
  12. Levothym
  13. Levotinine
  14. Oxitriptan
  15. Oxyfan
  16. Oxytryptophan
  17. Pretonine
  18. Quietim
  19. Serotonyl
  20. Telesol
  21. Triptene
Chemical FormulaC11H12N2O3
Average Molecular Weight220.2246
Monoisotopic Molecular Weight220.08479226
IUPAC Name2-amino-3-(5-hydroxy-1H-indol-3-yl)propanoic acid
Traditional NameDL-5-hydroxytryptophan
CAS Registry Number4350-09-8
InChI Identifier
Chemical Taxonomy
DescriptionThis compound belongs to the class of organic compounds known as serotonins. These are compounds containing a serotonin moiety, which consists of an indole that bears an aminoethyl a position 2 and a hydroxyl group at position 5.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassIndoles and derivatives
Sub ClassTryptamines and derivatives
Direct ParentSerotonins
Alternative Parents
  • Serotonin
  • Indolyl carboxylic acid derivative
  • Hydroxyindole
  • Alpha-amino acid or derivatives
  • Alpha-amino acid
  • Indole
  • Aralkylamine
  • Amino fatty acid
  • Fatty acyl
  • Benzenoid
  • Substituted pyrrole
  • Heteroaromatic compound
  • Pyrrole
  • Azacycle
  • Monocarboxylic acid or derivatives
  • Carboxylic acid
  • Carboxylic acid derivative
  • Hydrocarbon derivative
  • Primary amine
  • Organooxygen compound
  • Organonitrogen compound
  • Primary aliphatic amine
  • Carbonyl group
  • Amine
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External DescriptorsNot Available
StatusDetected and Quantified
  • Endogenous
  • Protein synthesis, amino acid biosynthesis
ApplicationNot Available
Cellular locations
  • Cytoplasm
Physical Properties
Experimental Properties
Melting Point293 - 298 °CNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogP-2.051Not Available
Predicted Properties
Water Solubility3.63 mg/mLALOGPS
pKa (Strongest Acidic)2.15ChemAxon
pKa (Strongest Basic)9.18ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count4ChemAxon
Polar Surface Area99.34 Å2ChemAxon
Rotatable Bond Count3ChemAxon
Refractivity58.18 m3·mol-1ChemAxon
Polarizability22.03 Å3ChemAxon
Number of Rings2ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Biological Properties
Cellular Locations
  • Cytoplasm
Biofluid Locations
  • Blood
  • Cerebrospinal Fluid (CSF)
  • Urine
Tissue Location
  • Prostate
Tryptophan MetabolismSMP00063map00380
Normal Concentrations
BloodDetected and Quantified0.018 +/- 0.0027 uMAdult (>18 years old)BothNormal details
Cerebrospinal Fluid (CSF)Detected and Quantified0.005 (0.00-0.010) uMInfant (0-1 year old)BothNormal details
UrineDetected and Quantified0.0078 umol/mmol creatinineAdult (>18 years old)BothNormal details
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDDB02959
DrugBank Metabolite IDNot Available
Phenol Explorer Compound IDNot Available
Phenol Explorer Metabolite IDNot Available
FoodDB IDFDB006231
KNApSAcK IDC00001371
Chemspider ID141
KEGG Compound IDC01017
BiGG ID36630
Wikipedia Link5-HTP
NuGOwiki LinkHMDB00472
Metagene LinkHMDB00472
METLIN IDNot Available
PubChem Compound144
PDB IDNot Available
ChEBI ID28171
Synthesis ReferenceBoroda, E.; Rakowska, S.; Kanski, R.; Kanska, M. Enzymatic synthesis of L-tryptophan and 5'-hydroxy-L-tryptophan labeled with deuterium and tritium at the a-carbon position. Journal of Labelled Compounds & Radiopharmaceuticals (2003), 46(8), 691-698.
Material Safety Data Sheet (MSDS)Download (PDF)
General References
  1. Sreekumar A, Poisson LM, Rajendiran TM, Khan AP, Cao Q, Yu J, Laxman B, Mehra R, Lonigro RJ, Li Y, Nyati MK, Ahsan A, Kalyana-Sundaram S, Han B, Cao X, Byun J, Omenn GS, Ghosh D, Pennathur S, Alexander DC, Berger A, Shuster JR, Wei JT, Varambally S, Beecher C, Chinnaiyan AM: Metabolomic profiles delineate potential role for sarcosine in prostate cancer progression. Nature. 2009 Feb 12;457(7231):910-4. [19212411 ]
  2. Magnussen I, Van Woert MH: Human pharmacokinetics of long term 5-hydroxytryptophan combined with decarboxylase inhibitors. Eur J Clin Pharmacol. 1982;23(1):81-6. [6182005 ]
  3. Li Kam Wa TC, Freestone S, Samson RR, Johnson NR, Lee MR: A comparison of the renal and neuroendocrine effects of two 5-hydroxytryptamine renal prodrugs in normal man. Clin Sci (Lond). 1993 Nov;85(5):607-14. [8287650 ]
  4. Li Kam Wa TC, Freestone S, Samson RR, Johnston NR, Lee MR: Renal metabolism and effects of the glutamyl derivatives of L-dopa and 5-hydroxytryptophan in man. Clin Sci (Lond). 1996 Aug;91(2):177-85. [8795441 ]
  5. Iacono RP, Kuniyoshi SM, Ahlman JR, Zimmerman GJ, Maeda G, Pearlstein RD: Concentrations of indoleamine metabolic intermediates in the ventricular cerebrospinal fluid of advanced Parkinson's patients with severe postural instability and gait disorders. J Neural Transm. 1997;104(4-5):451-9. [9295177 ]
  6. Verbeek MM, Geurtz PB, Willemsen MA, Wevers RA: Aromatic L-amino acid decarboxylase enzyme activity in deficient patients and heterozygotes. Mol Genet Metab. 2007 Apr;90(4):363-9. Epub 2007 Jan 19. [17240182 ]
  7. Turner EH, Loftis JM, Blackwell AD: Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan. Pharmacol Ther. 2006 Mar;109(3):325-38. Epub 2005 Jul 14. [16023217 ]
  8. Bouchard S, Roberge AG: Biochemical properties and kinetic parameters of dihydroxyphenylalanine--5-hydroxytryptophan decarboxylase in brain, liver, and adrenals of cat. Can J Biochem. 1979 Jul;57(7):1014-8. [39668 ]
  9. Amamoto T, Sarai K: On the tryptophan-serotonin metabolism in manic-depressive disorders. Changes in plasma 5-HT and 5-HIAA levels and urinary 5-HIAA excretion following oral loading of L-5HTP in patients with depression. Hiroshima J Med Sci. 1976 Sep;25(2-3):135-40. [1088369 ]
  10. Caruso I, Sarzi Puttini P, Cazzola M, Azzolini V: Double-blind study of 5-hydroxytryptophan versus placebo in the treatment of primary fibromyalgia syndrome. J Int Med Res. 1990 May-Jun;18(3):201-9. [2193835 ]
  11. De Benedittis G, Massei R: Serotonin precursors in chronic primary headache. A double-blind cross-over study with L-5-hydroxytryptophan vs. placebo. J Neurosurg Sci. 1985 Jul-Sep;29(3):239-48. [3913752 ]
  12. Magnussen I, Jensen TS, Rand JH, Van Woert MH: Plasma accumulation of metabolism of orally administered single dose L-5-hydroxytryptophan in man. Acta Pharmacol Toxicol (Copenh). 1981 Sep;49(3):184-9. [6175178 ]
  13. Rahman MK, Nagatsu T, Sakurai T, Hori S, Abe M, Matsuda M: Effect of pyridoxal phosphate deficiency on aromatic L-amino acid decarboxylase activity with L-DOPA and L-5-hydroxytryptophan as substrates in rats. Jpn J Pharmacol. 1982 Oct;32(5):803-11. [6983619 ]
  14. Sternberg EM, Van Woert MH, Young SN, Magnussen I, Baker H, Gauthier S, Osterland CK: Development of a scleroderma-like illness during therapy with L-5-hydroxytryptophan and carbidopa. N Engl J Med. 1980 Oct 2;303(14):782-7. [6997735 ]
  15. Trouillas P, Serratrice G, Laplane D, Rascol A, Augustin P, Barroche G, Clanet M, Degos CF, Desnuelle C, Dumas R, et al.: Levorotatory form of 5-hydroxytryptophan in Friedreich's ataxia. Results of a double-blind drug-placebo cooperative study. Arch Neurol. 1995 May;52(5):456-60. [7733839 ]
  16. Birdsall TC: 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Altern Med Rev. 1998 Aug;3(4):271-80. [9727088 ]
  17. Birdsall TC: 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Altern Med Rev. 1998 Aug;3(4):271-80. [9727088 ]
  18. Shaw K, Turner J, Del Mar C: Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database Syst Rev. 2002;(1):CD003198. [11869656 ]
  19. Turner EH, Blackwell AD: 5-Hydroxytryptophan plus SSRIs for interferon-induced depression: synergistic mechanisms for normalizing synaptic serotonin. Med Hypotheses. 2005;65(1):138-44. [15893130 ]
  20. Nakatani Y, Sato-Suzuki I, Tsujino N, Nakasato A, Seki Y, Fumoto M, Arita H: Augmented brain 5-HT crosses the blood-brain barrier through the 5-HT transporter in rat. Eur J Neurosci. 2008 May;27(9):2466-72. doi: 10.1111/j.1460-9568.2008.06201.x. [18445233 ]


General function:
Involved in carboxy-lyase activity
Specific function:
Catalyzes the decarboxylation of L-3,4-dihydroxyphenylalanine (DOPA) to dopamine, L-5-hydroxytryptophan to serotonin and L-tryptophan to tryptamine.
Gene Name:
Uniprot ID:
Molecular weight:
General function:
Involved in heme binding
Specific function:
Catalyzes the cleavage of the pyrrol ring of tryptophan and incorporates both atoms of a molecule of oxygen.
Gene Name:
Uniprot ID:
Molecular weight:
General function:
Involved in amino acid binding
Specific function:
Not Available
Gene Name:
Uniprot ID:
Molecular weight:
General function:
Involved in amino acid binding
Specific function:
Not Available
Gene Name:
Uniprot ID:
Molecular weight:
General function:
Involved in heme binding
Specific function:
Catalyzes the first and rate-limiting step in the kynurenine pathway of tryptophan catabolism.
Gene Name:
Uniprot ID:
Molecular weight: