5-Hydroxytryptophan
822579
225919200
2008-07-16T00:39:54Z
68.188.188.179
Linked carbidopa
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|ImageFile=5-hydroxytryptophan.png
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|ImageFile2=5-htp-3d.png
|IUPACName=2-amino-3- (5-hydroxy-1H-indol-3-yl) propanoic acid
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|Section1= {{Chembox Identifiers
| CASNo=56-69-9
| PubChem=144
| SMILES=C1=CC2=C(C=C1O)C (=CN2)CC(C(=O)O)N
| MeSHName=5-Hydroxytryptophan
}}
|Section2= {{Chembox Properties
| Formula=C<sub>11</sub>H<sub>12</sub>N<sub>2</sub>O<sub>3</sub>
| MolarMass=220.225
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|Section3= {{Chembox Hazards
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'''5-Hydroxytryptophan''' or '''5-HTP''' is a naturally-occurring [[amino acid]], a [[precursor (chemistry)|precursor]] to the [[neurotransmitter]] [[serotonin]] and an intermediate in [[tryptophan]] [[metabolism]]. It is marketed in the [[United States]] and other countries as a dietary supplement for use as an [[antidepressant]], [[appetite suppressant]], and [[sleep aid]].
==Metabolism==
5-Hydroxytryptophan is [[decarboxylation|decarboxylated]] to [[serotonin]] (5-hydroxytryptamine or 5-HT) by the [[enzyme]] [[aromatic-L-amino-acid decarboxylase]] with the help of [[Vitamin B6]].<ref>{{cite journal |author=Rahman MK, Nagatsu T, Sakurai T, Hori S, Abe M, Matsuda M |title=Effect of pyridoxal phosphate deficiency on aromatic L-amino acid decarboxylase activity with L-DOPA and L-5-hydroxytryptophan as substrates in rats |journal=Jpn. J. Pharmacol. |volume=32 |issue=5 |pages=803–11 |year=1982 |pmid=6983619 |doi=10.1254/jjp.32.803}}</ref>
This reaction occurs both in nervous tissue and in the liver.<ref>Bouchard S, Bousquet C, Roberge AG. Characteristics of dihydroxyphenylalanine/5-hydroxytryptophan decarboxylase activity in brain and liver of cat. J Neurochem. 1981 Sep;37(3):781-7. PMID 6974228</ref> 5-HTP crosses the [[blood-brain barrier]], while 5-HT does not. Excess 5-HTP, especially when administered with [[Vitamin B6]], is thought to be metabolized and excreted.<ref>{{cite journal |author=Bouchard S, Roberge AG |title=Biochemical properties and kinetic parameters of dihydroxyphenylalanine--5-hydroxytryptophan decarboxylase in brain, liver, and adrenals of cat |journal=Can. J. Biochem. |volume=57 |issue=7 |pages=1014–8 |year=1979 |pmid=39668 |doi=}}</ref><ref>{{cite journal |author=Amamoto T, Sarai K |title=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 |journal=Hiroshima J. Med. Sci. |volume=25 |issue=2-3 |pages=135–40 |year=1976 |pmid=1088369 |doi=}}</ref>
==Pharmacology==
The psychoactive action of 5-HTP is thought to derive from its effect on serotonin synthesis in [[central nervous system]] tissue. It is believed that an artificially high supply of 5-HTP causes the brain's serotonin-producing neurons to increase production. Increased serotonin production then leads to increased serotonin release.
Research shows that co-administration with [[carbidopa]] greatly increases [[blood plasma|plasma]] 5-HTP levels.<ref>{{cite journal |author=Magnussen I, Jensen TS, Rand JH, Van Woert MH |title=Plasma accumulation of metabolism of orally administered single dose L-5-hydroxytryptophan in man |journal=Acta pharmacologica et toxicologica |volume=49 |issue=3 |pages=184–9 |year=1981 |pmid=6175178 |doi=}}</ref> However, several studies have reported that 5-HTP is effective even without a PDI.<!-- Removed: "and refuting its adverse effects on the heart". The studies did not address that issue. --><ref>{{cite journal |author=Birdsall TC |title=5-Hydroxytryptophan: a clinically-effective serotonin precursor |journal=Alternative medicine review : a journal of clinical therapeutic |volume=3 |issue=4 |pages=271–80 |year=1998 |pmid=9727088 |doi=}}</ref><ref>[http://www.mwilliamson.com/5htps.htm VRP's Articel on 5-HTP Safety<!-- Bot generated title -->]</ref>
Other studies have indicated the risk of a [[scleroderma]]-like condition resulting from the combination of 5-HTP and carbidopa.<ref>{{cite journal |author=Sternberg EM, Van Woert MH, Young SN, ''et al'' |title=Development of a scleroderma-like illness during therapy with L-5-hydroxytryptophan and carbidopa |journal=N. Engl. J. Med. |volume=303 |issue=14 |pages=782–7 |year=1980 |pmid=6997735 |doi=}}</ref>
==5-HTP as therapeutic supplement==
5-HTP, which is found in minute amounts in certain foods like [[turkey]] and [[cheese]]{{Fact|date=October 2007}}, is often sold as an over-the-counter therapeutic supplement. In this case, it is usually sourced from the seeds of ''[[Griffonia simplicifolia]]''. 5-HTP in supplement form is typically sold in 50 mg or 100 mg [[gelatin]] or vegetarian capsules.
===Research===
[[Image:trp-5ht-pathway.png|thumb|600px|Metabolic pathway from tryptophan to serotonin.]]
5-HTP has been shown to be as effective as Imipramine for the treatment of [[clinical depression|depression]]. <ref name="meyers2000">''Altern Med Rev.'' 2000 Feb; 5(1), 64-71 [http://www.ncbi.nlm.nih.gov/entrez?cmd=retrieve&db=pubmed&list_uids=10696120 ''Use of neurotransmitter precursors for treatment of depression.''], Meyers S.</ref>
Current research shows promise in using 5-HTP for treating children with [[night terror]]s. After six months of use 83.9% of the children treated with 5-HTP were free from their persistent sleep terrors. <ref>''Eur J Pediatr.'' 2004 Jul;163(7):402-7. Epub 2004 May 14. [http://www.ncbi.nlm.nih.gov/entrez?cmd=retrieve&db=pubmed&list_uids=15146330 ''L -5-Hydroxytryptophan treatment of sleep terrors in children''], Bruni O, Ferri R, Miano S, Verrillo E.</ref>
Some persons with [[fibromyalgia]] find that 5-HTP improves their symptoms.<ref>''J Int Med Res.'' 1992 Apr;20(2):182-9 [http://www.ncbi.nlm.nih.gov/entrez?cmd=retrieve&db=pubmed&list_uids=1521674 ''Primary fibromyalgia syndrome and 5-hydroxy-L-tryptophan: a 90-day open study.''], Sarzi Puttini P, Caruso I.</ref> Fibromyalgia sufferers report improvement in sleep, depression, pain and all major complaints related to fibromyalgia.<ref>''J Int Med Res.'' 1990 May-Jun;18(3):201-9. [http://www.ncbi.nlm.nih.gov/entrez?cmd=retrieve&db=pubmed&list_uids=2193835 ''Double-blind study of 5-hydroxytryptophan versus placebo in the treatment of primary fibromyalgia syndrome.''], Caruso I, Sarzi Puttini P, Cazzola M, Azzolini V.</ref> Studies are continuing to refine dosage and continued use.
It is also used as a prophylactic against [[Rebound headache|chronic daily headache]]. <ref>{{cite journal |author=De Benedittis G, Massei R |title=Serotonin precursors in chronic primary headache. A double-blind cross-over study with L-5-hydroxytryptophan vs. placebo |journal=Journal of Neurosurgical Sciences |volume=29 |issue=3 |pages=239−48 |year=1985 |pmid=3913752}}</ref> 5-HTP may also be useful in treatment for migraines, since studies have shown that migraines occur when serotonin levels are low.
5-HTP has been shown to be an effective appetite suppressant. <Cn>
===Dosage===
Most supplement providers recommend 50 mg or 100 mg 5-HTP, one to three times per day. Most clinical studies have tested doses of 200-300 mg/day, although one study tested doses as large as 3250 mg/day. In some clinical studies 5-HTP is administered with [[carbidopa]], which substantially changes 5-HTP's pharmacology.<ref>{{cite journal |author=Magnussen I, Van Woert MH |title=Human pharmacokinetics of long term 5-hydroxytryptophan combined with decarboxylase inhibitors |journal=Eur. J. Clin. Pharmacol. |volume=23 |issue=1 |pages=81–6 |year=1982 |pmid=6182005 |doi=10.1007/BF01061381}}</ref> Consumption with other proteins or amino acids will decrease absorption in the digestive tract. <ref name="pubmed: turner et al">{{cite journal |author=Turner EH, Loftis JM, Blackwell AD |title=Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan |journal=Pharmacol. Ther. |volume=109 |issue=3 |pages=325–38 |year=2006 |pmid=16023217 |doi=10.1016/j.pharmthera.2005.06.004}}</ref>
Serotonin syndrome was not observed in several studies that augmented traditional antidepressant therapy with 5-HTP, even though the combination therapy was expected to increase the risk of serotonin syndrome above 5-HTP alone.<ref name="pubmed: turner et al"/> Some users report high doses (300 mg and over) can produce nausea and vomiting.<ref>{{cite web |url=http://www.erowid.org/experiences/exp.cgi?S1=138 |title=Erowid Experience Vaults: Search Results |accessdate=2007-06-09 |format= |work=}}</ref> High doses may be damaging to the liver.
==See also==
*[[Serotonin]]
*[[Tryptophan]]
*[[Vitamin B6]]
*[[Pyridoxal-phosphate|Pyridoxal Phosphate (PLP)]] - Bioactive form of vitamin B6
==References==
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==Further reading==
* {{cite journal |author=den Boer JA, Westenberg HG |title=Behavioral, neuroendocrine, and biochemical effects of 5-hydroxytryptophan administration in panic disorder |journal=Psychiatry research |volume=31 |issue=3 |pages=267–78 |year=1990 |pmid=2139731 |doi=}}
* {{cite journal |author=Angst J, Woggon B, Schoepf J |title=The treatment of depression with L-5-hydroxytryptophan versus imipramine. Results of two open and one double-blind study |journal=Archiv für Psychiatrie und Nervenkrankheiten |volume=224 |issue=2 |pages=175–86 |year=1977 |pmid=336002 |doi=}}
*[http://cms.psychologytoday.com/articles/pto-19981101-000022.html article] at [[Psychology Today]]
* {{cite journal |author=Turner EH, Loftis JM, Blackwell AD |title=Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan |journal=Pharmacol. Ther. |volume=109 |issue=3 |pages=325–38 |year=2006 |pmid=16023217 |doi=10.1016/j.pharmthera.2005.06.004}}
*[http://www.erowid.org/smarts/tryptophan/tryptophan.shtml Erowid L-tryptophan and 5-HTP Information Vault] at [[Erowid]]
*[http://www.umm.edu/altmed/articles/5-htp-000283.htm 5-Hydroxytryptophan (5-HTP) Supplement Information] at [[University of Maryland, Baltimore|University of Maryland]] Medical Center
*[http://www.dancesafe.org/slideshow/ MDMA slideshow] at [[DanceSafe]]
{{Neurotransmitter metabolism intermediates}}
{{DEFAULTSORT:Hydroxytryptophan, 5-}}
[[Category:Neurotransmitters]]
[[Category:Dietary supplements]]
[[Category:Nootropics]]
[[Category:Tryptamines]]
[[Category:Amino acids]]
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