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(Redirected from 5htp)
'5-Hydroxytryptophan' or '5-HTP' is a naturally-occurring amino acid, a 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.
5-Hydroxytryptophan
★ is decarboxylated to serotonin (5-hydroxytryptamine or 5-HT) by the enzyme aromatic-L-amino-acid decarboxylase with the help of Vitamin B6 [1].
This reaction occurs both in nervous tissue and in the liver [2]. 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 before reaching the brain. [3][4]
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.
Some doctors suggest that 5-HTP be administered with a peripheral decarboxylase inhibitor (PDI) such as carbidopa (and without Vitamin B6, see above) in order to prevent 5-HTP's metabolism in the liver, which can lead to elevated levels of serotonin in the bloodstream (and their side effects which include vomiting, and potentially fibrosis of the heart).[5] Research shows that co-administration with carbidopa greatly increases plasma 5-HTP levels.[6]However, several studies have reported that 5-HTP is effective even without a PDI. [7][8]
Other studies have indicated the risk of a scleroderma-like condition resulting from the combination of 5-HTP and carbidopa.[9]
5-HTP, which is found in infinitesimal amounts in certain foods like turkey and cheese, is often sold as an over-the-counter therapeutic supplement. In this case, it is usually sourced from the seeds of ''Griffonia simplicifolia''. Production of 5-HTP as a supplement increased when a similar serotonin-altering supplement, L-tryptophan, was temporarily barred from sale in the United States by the FDA. 5-HTP in supplement form is typically sold in 50 mg or 100 mg gelatin capsules.
It has been alleged that 5-HTP can be used to treat mental disorders such as depression. Unfortunately, the studies to date are incomplete. Reviews of these studies do indicate that potential exists for 5-HTP in the treatment of depression, but further trials are stressed as necessary before arriving at any firm conclusion.[10]
Similar deficits have been observed in long term/high dose psychostimulant users. Such deficits are especially apparent in those who have used amphetamine and methamphetamine. Amphetamines and to a lesser extent, cocaine, can damage serotonergic neurons in the CNS. Similar benefits have been seen in those with cognitive deficits resulting from psychostimulant use.[11]
Current research shows promise in using 5-HTP for treating children with night terrors. After 6 months of use 83.9% of the children treated with 5-HTP were free from their persistent nightmares. [12]
Some persons with fibromyalgia find that 5-HTP improves their symptoms.[13] Fibromyalgia sufferers report improvement in sleep, depression, pain and all major complaints related to fibromyalgia.[14] Studies are continuing to refine dosage and continued use.
In recent years 5-HTP has been sold by health food companies as an alternative treatment for depression and mood disorders. Its role as an intermediary in the biosynthesis of serotonin indicates that this chemical may indeed be effective in treating these and other serotonin-related disorders, but there is some debate on the conclusions of the clinical trials which have been carried out using the drug. It is also used as a prophylactic against chronic daily headache. [15]
5-HTP is also used as a supplement by users of MDMA (ecstasy) to help replenish depleted serotonin, in an attempt to alleviate to a degree the depression and overall mental unsettlement that sometimes occurs in the days following MDMA usage. 5-HTP is less commonly used immediately before the use of MDMA as a means to both further reduce the negative psychological effects of depleted serotonin, and as an attempt to boost the effects of MDMA. Some users report a moderate muting of the MDMA effect.[16]
Though there is no official 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 many clinical studies, 5-HTP is administered with carbidopa, which substantially changes 5-HTP's pharmacology, e.g. [17]
Although many studies do not report a dosing schedule, the majority of those that do have reported using two to four doses split throughout the day. The most effective timing would be before sleep, and on an empty stomach(either/or preferably both), any other protein or amino acid will decrease absorption in the digestive tract. [18]
In theory, an overdose of 5-HTP could cause serotonin syndrome. However, 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. In dogs, doses of 23.6 mg/kg were found to cause toxic reactions, although the dose response curve for any animal with any drug will probably not scale to humans.[19] Some users report high doses (300 mg and over) can produce nausea and vomiting.[20] High doses may be damaging to the liver, due to the fact that the level of each amino acid in the blood must be tightly regulated by removal of any excess.
Promoters of 5-HTP claim that it causes fewer side effects than traditional antidepressants. Side effects of 5-HTP may include nausea, constipation, gas, drowsiness, or a decreased sex drive. It can also have adverse interactions with other natural and traditional drugs.
[1] From clinical experiences people may develop anxiety, numbness, paresthesias, breathing problems, palpitations, chest pain, hallucinations and insomnia.
★ Serotonin
★ Tryptophan
★ Vitamin B6
★ Pyridoxal Phosphate (PLP) - Bioactive form of vitamin B6
5-HTP
1. Effect of pyridoxal phosphate deficiency on aromatic L-amino acid decarboxylase activity with L-DOPA and L-5-hydroxytryptophan as substrates in rats, Rahman MK, Nagatsu T, Sakurai T, Hori S, Abe M, Matsuda M, , , Jpn. J. Pharmacol., 1982
2. 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
3. Biochemical properties and kinetic parameters of dihydroxyphenylalanine--5-hydroxytryptophan decarboxylase in brain, liver, and adrenals of cat, Bouchard S, Roberge AG, , , Can. J. Biochem., 1979
4. 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, Amamoto T, Sarai K, , , Hiroshima J. Med. Sci., 1976
5. Usenet post by Steven B. Harris: "5-HTP + B6 = Trouble; Doc Harris Presents Green Banana Award"
6. Plasma accumulation of metabolism of orally administered single dose L-5-hydroxytryptophan in man, Magnussen I, Jensen TS, Rand JH, Van Woert MH, , , Acta pharmacologica et toxicologica, 1981
7. 5-Hydroxytryptophan: a clinically-effective serotonin precursor, Birdsall TC, , , Alternative medicine review : a journal of clinical therapeutic, 1998
8. http://www.mwilliamson.com/5htps.htm
9. Development of a scleroderma-like illness during therapy with L-5-hydroxytryptophan and carbidopa, Sternberg EM, Van Woert MH, Young SN, ''et al'', , , N. Engl. J. Med., 1980
10. ''Altern Med Rev.'' 2000 Feb; 5(1), 64-71 ''Use of neurotransmitter precursors for treatment of depression.'', Meyers S.
11. ''Eur J Pharmacol.'' 2002 Jun 12;445(3):221-9. ''Involvement of 5-hydroxytryptamine neuronal system in Delta(9)-tetrahydrocannabinol-induced impairment of spatial memory.'', Egashira N, Mishima K, Katsurabayashi S, Yoshitake T, Matsumoto Y, Ishida J, Yamaguchi M, Iwasaki K, Fujiwara M.
12. ''Eur J Pediatr.'' 2004 Jul;163(7):402-7. Epub 2004 May 14. ''L -5-Hydroxytryptophan treatment of sleep terrors in children'', Bruni O, Ferri R, Miano S, Verrillo E.
13. ''J Int Med Res.'' 1992 Apr;20(2):182-9 ''Primary fibromyalgia syndrome and 5-hydroxy-L-tryptophan: a 90-day open study.'', Sarzi Puttini P, Caruso I.
14. ''J Int Med Res.'' 1990 May-Jun;18(3):201-9. ''Double-blind study of 5-hydroxytryptophan versus placebo in the treatment of primary fibromyalgia syndrome.'', Caruso I, Sarzi Puttini P, Cazzola M, Azzolini V.
15. Serotonin precursors in chronic primary headache. A double-blind cross-over study with L-5-hydroxytryptophan vs. placebo., De Benedittis G, Massei R, , , Journal of Neurosurgical Sciences, 1985
16. MDMA and 5-HTP information and advice
17. Human pharmacokinetics of long term 5-hydroxytryptophan combined with decarboxylase inhibitors, Magnussen I, Van Woert MH, , , Eur. J. Clin. Pharmacol., 1982
18. Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan, Turner EH, Loftis JM, Blackwell AD, , , Pharmacol. Ther., 2006
19. 5-Hydroxytryptophan toxicosis in dogs: 21 cases (1989-1999), Gwaltney-Brant SM, Albretsen JC, Khan SA, , , J. Am. Vet. Med. Assoc., 2000
20. Erowid Experience Vaults: Search Results
★ Information Paper on L-tryptophan and 5-hydroxy-L-tryptophan at Food and Drug Administration, February 2001
★ Behavioral, neuroendocrine, and biochemical effects of 5-hydroxytryptophan administration in panic disorder, den Boer JA, Westenberg HG, , , Psychiatry research, 1990
★ The treatment of depression with L-5-hydroxytryptophan versus imipramine. Results of two open and one double-blind study, Angst J, Woggon B, Schoepf J, , , Archiv für Psychiatrie und Nervenkrankheiten, 1977
★ article at Psychology Today
★ Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan, Turner EH, Loftis JM, Blackwell AD, , , Pharmacol. Ther., 2006
★ Erowid L-tryptophan and 5-HTP Information Vault at Erowid
★ 5-Hydroxytryptophan (5-HTP) Supplement Information at University of Maryland Medical Center
★ MDMA slideshow at DanceSafe
'5-Hydroxytryptophan' or '5-HTP' is a naturally-occurring amino acid, a 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.
| Contents |
| Metabolism |
| Pharmacology |
| 5-HTP as therapeutic supplement |
| Research |
| Uses |
| Dosage |
| Side effects |
| See also |
| References |
| Further reading |
Metabolism
5-Hydroxytryptophan
★ is decarboxylated to serotonin (5-hydroxytryptamine or 5-HT) by the enzyme aromatic-L-amino-acid decarboxylase with the help of Vitamin B6 [1].
Metabolic pathway from tryptophan to serotonin.
This reaction occurs both in nervous tissue and in the liver [2]. 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 before reaching the brain. [3][4]
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.
Some doctors suggest that 5-HTP be administered with a peripheral decarboxylase inhibitor (PDI) such as carbidopa (and without Vitamin B6, see above) in order to prevent 5-HTP's metabolism in the liver, which can lead to elevated levels of serotonin in the bloodstream (and their side effects which include vomiting, and potentially fibrosis of the heart).[5] Research shows that co-administration with carbidopa greatly increases plasma 5-HTP levels.[6]However, several studies have reported that 5-HTP is effective even without a PDI. [7][8]
Other studies have indicated the risk of a scleroderma-like condition resulting from the combination of 5-HTP and carbidopa.[9]
5-HTP as therapeutic supplement
5-HTP, which is found in infinitesimal amounts in certain foods like turkey and cheese, is often sold as an over-the-counter therapeutic supplement. In this case, it is usually sourced from the seeds of ''Griffonia simplicifolia''. Production of 5-HTP as a supplement increased when a similar serotonin-altering supplement, L-tryptophan, was temporarily barred from sale in the United States by the FDA. 5-HTP in supplement form is typically sold in 50 mg or 100 mg gelatin capsules.
Research
It has been alleged that 5-HTP can be used to treat mental disorders such as depression. Unfortunately, the studies to date are incomplete. Reviews of these studies do indicate that potential exists for 5-HTP in the treatment of depression, but further trials are stressed as necessary before arriving at any firm conclusion.[10]
Similar deficits have been observed in long term/high dose psychostimulant users. Such deficits are especially apparent in those who have used amphetamine and methamphetamine. Amphetamines and to a lesser extent, cocaine, can damage serotonergic neurons in the CNS. Similar benefits have been seen in those with cognitive deficits resulting from psychostimulant use.[11]
Current research shows promise in using 5-HTP for treating children with night terrors. After 6 months of use 83.9% of the children treated with 5-HTP were free from their persistent nightmares. [12]
Some persons with fibromyalgia find that 5-HTP improves their symptoms.[13] Fibromyalgia sufferers report improvement in sleep, depression, pain and all major complaints related to fibromyalgia.[14] Studies are continuing to refine dosage and continued use.
Uses
In recent years 5-HTP has been sold by health food companies as an alternative treatment for depression and mood disorders. Its role as an intermediary in the biosynthesis of serotonin indicates that this chemical may indeed be effective in treating these and other serotonin-related disorders, but there is some debate on the conclusions of the clinical trials which have been carried out using the drug. It is also used as a prophylactic against chronic daily headache. [15]
5-HTP is also used as a supplement by users of MDMA (ecstasy) to help replenish depleted serotonin, in an attempt to alleviate to a degree the depression and overall mental unsettlement that sometimes occurs in the days following MDMA usage. 5-HTP is less commonly used immediately before the use of MDMA as a means to both further reduce the negative psychological effects of depleted serotonin, and as an attempt to boost the effects of MDMA. Some users report a moderate muting of the MDMA effect.[16]
Dosage
Though there is no official 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 many clinical studies, 5-HTP is administered with carbidopa, which substantially changes 5-HTP's pharmacology, e.g. [17]
Although many studies do not report a dosing schedule, the majority of those that do have reported using two to four doses split throughout the day. The most effective timing would be before sleep, and on an empty stomach(either/or preferably both), any other protein or amino acid will decrease absorption in the digestive tract. [18]
In theory, an overdose of 5-HTP could cause serotonin syndrome. However, 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. In dogs, doses of 23.6 mg/kg were found to cause toxic reactions, although the dose response curve for any animal with any drug will probably not scale to humans.[19] Some users report high doses (300 mg and over) can produce nausea and vomiting.[20] High doses may be damaging to the liver, due to the fact that the level of each amino acid in the blood must be tightly regulated by removal of any excess.
Side effects
Promoters of 5-HTP claim that it causes fewer side effects than traditional antidepressants. Side effects of 5-HTP may include nausea, constipation, gas, drowsiness, or a decreased sex drive. It can also have adverse interactions with other natural and traditional drugs.
[1] From clinical experiences people may develop anxiety, numbness, paresthesias, breathing problems, palpitations, chest pain, hallucinations and insomnia.
See also
★ Serotonin
★ Tryptophan
★ Vitamin B6
★ Pyridoxal Phosphate (PLP) - Bioactive form of vitamin B6
5-HTP
References
1. Effect of pyridoxal phosphate deficiency on aromatic L-amino acid decarboxylase activity with L-DOPA and L-5-hydroxytryptophan as substrates in rats, Rahman MK, Nagatsu T, Sakurai T, Hori S, Abe M, Matsuda M, , , Jpn. J. Pharmacol., 1982
2. 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
3. Biochemical properties and kinetic parameters of dihydroxyphenylalanine--5-hydroxytryptophan decarboxylase in brain, liver, and adrenals of cat, Bouchard S, Roberge AG, , , Can. J. Biochem., 1979
4. 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, Amamoto T, Sarai K, , , Hiroshima J. Med. Sci., 1976
5. Usenet post by Steven B. Harris: "5-HTP + B6 = Trouble; Doc Harris Presents Green Banana Award"
6. Plasma accumulation of metabolism of orally administered single dose L-5-hydroxytryptophan in man, Magnussen I, Jensen TS, Rand JH, Van Woert MH, , , Acta pharmacologica et toxicologica, 1981
7. 5-Hydroxytryptophan: a clinically-effective serotonin precursor, Birdsall TC, , , Alternative medicine review : a journal of clinical therapeutic, 1998
8. http://www.mwilliamson.com/5htps.htm
9. Development of a scleroderma-like illness during therapy with L-5-hydroxytryptophan and carbidopa, Sternberg EM, Van Woert MH, Young SN, ''et al'', , , N. Engl. J. Med., 1980
10. ''Altern Med Rev.'' 2000 Feb; 5(1), 64-71 ''Use of neurotransmitter precursors for treatment of depression.'', Meyers S.
11. ''Eur J Pharmacol.'' 2002 Jun 12;445(3):221-9. ''Involvement of 5-hydroxytryptamine neuronal system in Delta(9)-tetrahydrocannabinol-induced impairment of spatial memory.'', Egashira N, Mishima K, Katsurabayashi S, Yoshitake T, Matsumoto Y, Ishida J, Yamaguchi M, Iwasaki K, Fujiwara M.
12. ''Eur J Pediatr.'' 2004 Jul;163(7):402-7. Epub 2004 May 14. ''L -5-Hydroxytryptophan treatment of sleep terrors in children'', Bruni O, Ferri R, Miano S, Verrillo E.
13. ''J Int Med Res.'' 1992 Apr;20(2):182-9 ''Primary fibromyalgia syndrome and 5-hydroxy-L-tryptophan: a 90-day open study.'', Sarzi Puttini P, Caruso I.
14. ''J Int Med Res.'' 1990 May-Jun;18(3):201-9. ''Double-blind study of 5-hydroxytryptophan versus placebo in the treatment of primary fibromyalgia syndrome.'', Caruso I, Sarzi Puttini P, Cazzola M, Azzolini V.
15. Serotonin precursors in chronic primary headache. A double-blind cross-over study with L-5-hydroxytryptophan vs. placebo., De Benedittis G, Massei R, , , Journal of Neurosurgical Sciences, 1985
16. MDMA and 5-HTP information and advice
17. Human pharmacokinetics of long term 5-hydroxytryptophan combined with decarboxylase inhibitors, Magnussen I, Van Woert MH, , , Eur. J. Clin. Pharmacol., 1982
18. Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan, Turner EH, Loftis JM, Blackwell AD, , , Pharmacol. Ther., 2006
19. 5-Hydroxytryptophan toxicosis in dogs: 21 cases (1989-1999), Gwaltney-Brant SM, Albretsen JC, Khan SA, , , J. Am. Vet. Med. Assoc., 2000
20. Erowid Experience Vaults: Search Results
Further reading
★ Information Paper on L-tryptophan and 5-hydroxy-L-tryptophan at Food and Drug Administration, February 2001
★ Behavioral, neuroendocrine, and biochemical effects of 5-hydroxytryptophan administration in panic disorder, den Boer JA, Westenberg HG, , , Psychiatry research, 1990
★ The treatment of depression with L-5-hydroxytryptophan versus imipramine. Results of two open and one double-blind study, Angst J, Woggon B, Schoepf J, , , Archiv für Psychiatrie und Nervenkrankheiten, 1977
★ article at Psychology Today
★ Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan, Turner EH, Loftis JM, Blackwell AD, , , Pharmacol. Ther., 2006
★ Erowid L-tryptophan and 5-HTP Information Vault at Erowid
★ 5-Hydroxytryptophan (5-HTP) Supplement Information at University of Maryland Medical Center
★ MDMA slideshow at DanceSafe
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