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5-Hydroxytryptophan

 
5 Hydroxytryptophan

 
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5-Hydroxytryptophan
 
 
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5-Hydroxytryptophan or 5-HTP is a naturally occurring amino acid
Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
, a precursor
Precursor (chemistry)

In chemistry, a precursor is a chemical compound that participates in the chemical reaction that produces another compound. In biochemistry, the term "precursor" is used more specifically to refer to a chemical compound preceding another in a metabolic pathway....
 to the neurotransmitter
Neurotransmitter

Neurotransmitters are chemistry which relay, amplify and modulate signals between a neuron and another cell . Neurotransmitters are packaged into vesicles that cluster beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to receptors in the membrane on the postsynaptic side of...
 serotonin
Serotonin

Serotonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract of animals including humans....
 and an intermediate in tryptophan
Tryptophan

Tryptophan is one of the 20 List of standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG....
 metabolism
Metabolism

Metabolism is the set of chemical reactions that occur in living organisms in order to maintain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments....
. It is marketed in the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
 and other countries as a dietary supplement for use as an antidepressant
Antidepressant

An antidepressant is a psychiatric medication used for alleviating major depressive disorder or dysthymia. Drug groups known as MAOIs, tricyclics, and second-generation antidepressants such as SSRIs, and serotonin-norepinephrine reuptake inhibitors are particularly associated with the term....
, appetite suppressant, and sleep aid, however, according to a 2001 meta-analysis, insufficient high quality research has been done to establish that it is efficacious.

droxytryptophan is decarboxylated
Decarboxylation

Decarboxylation is any chemical reaction in which a carboxyl group is split off from a compound as carbon dioxide ....
 to serotonin
Serotonin

Serotonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract of animals including humans....
 (5-hydroxytryptamine or 5-HT) by the enzyme
Enzyme

Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
 aromatic-L-amino-acid decarboxylase with the help of Vitamin B6
Vitamin B6

Vitamin B6 is a water-soluble vitamin and is part of the vitamin B complex group. Pyridoxal phosphate is the active form and is a cofactor in many reactions of amino acid metabolism, including transamination, deamination, and decarboxylation....
.

This reaction occurs both in nervous tissue and in the liver.






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5-Hydroxytryptophan or 5-HTP is a naturally occurring amino acid
Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
, a precursor
Precursor (chemistry)

In chemistry, a precursor is a chemical compound that participates in the chemical reaction that produces another compound. In biochemistry, the term "precursor" is used more specifically to refer to a chemical compound preceding another in a metabolic pathway....
 to the neurotransmitter
Neurotransmitter

Neurotransmitters are chemistry which relay, amplify and modulate signals between a neuron and another cell . Neurotransmitters are packaged into vesicles that cluster beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to receptors in the membrane on the postsynaptic side of...
 serotonin
Serotonin

Serotonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract of animals including humans....
 and an intermediate in tryptophan
Tryptophan

Tryptophan is one of the 20 List of standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG....
 metabolism
Metabolism

Metabolism is the set of chemical reactions that occur in living organisms in order to maintain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments....
. It is marketed in the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
 and other countries as a dietary supplement for use as an antidepressant
Antidepressant

An antidepressant is a psychiatric medication used for alleviating major depressive disorder or dysthymia. Drug groups known as MAOIs, tricyclics, and second-generation antidepressants such as SSRIs, and serotonin-norepinephrine reuptake inhibitors are particularly associated with the term....
, appetite suppressant, and sleep aid, however, according to a 2001 meta-analysis, insufficient high quality research has been done to establish that it is efficacious.

Metabolism

5-Hydroxytryptophan is decarboxylated
Decarboxylation

Decarboxylation is any chemical reaction in which a carboxyl group is split off from a compound as carbon dioxide ....
 to serotonin
Serotonin

Serotonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract of animals including humans....
 (5-hydroxytryptamine or 5-HT) by the enzyme
Enzyme

Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
 aromatic-L-amino-acid decarboxylase with the help of Vitamin B6
Vitamin B6

Vitamin B6 is a water-soluble vitamin and is part of the vitamin B complex group. Pyridoxal phosphate is the active form and is a cofactor in many reactions of amino acid metabolism, including transamination, deamination, and decarboxylation....
.

This reaction occurs both in nervous tissue and in the liver. 5-HTP crosses the blood-brain barrier
Blood-brain barrier

The blood-brain barrier is a metabolic or cellular structure in the central nervous system that restricts the passage of various chemical substances and microscopic objects between the bloodstream and the neural tissue itself, while still allowing the passage of substances essential to metabolism function ....
, while 5-HT does not. Excess 5-HTP, especially when administered with Vitamin B6
Vitamin B6

Vitamin B6 is a water-soluble vitamin and is part of the vitamin B complex group. Pyridoxal phosphate is the active form and is a cofactor in many reactions of amino acid metabolism, including transamination, deamination, and decarboxylation....
, is thought to be metabolized and excreted.

Pharmacology

The psychoactive action of 5-HTP is thought to derive from its effect on serotonin synthesis in central nervous system
Central nervous system

The central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of multicellular organisms....
 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
Carbidopa

Carbidopa is a medication given to people with Parkinson's disease in order to inhibit peripheral metabolism of levodopa....
 greatly increases plasma
Blood plasma

Blood plasma is the liquid component of blood, in which the blood cells are suspended. It makes up about 55% of total blood volume. It is composed of mostly water , and contains dissolved proteins, glucose, clotting factors, mineral ions, Hormone and carbon dioxide ....
 5-HTP levels. However, several studies have reported that 5-HTP is effective even without a peripheral decarboxylase inhibitor (e.g. carbidopa). Other studies have indicated the risk of a scleroderma
Scleroderma

Systemic scleroderma is a systemic connective tissue disease.It is also known as "systemic Sclerosis "....
-like condition resulting from the combination of 5-HTP and carbidopa.

As a therapeutic supplement

5-HTP, which is found in minute amounts in certain foods like cheese
Cheese

Cheese is a food consisting of proteins and fat from milk, usually the milk of cattle, Water Buffalo, goats, or sheep's milk. It is produced by Coagulation of the milk protein casein....
 and the white meat of poultry
Poultry

Poultry is the category of domesticated birds which some people keep for the purpose of collecting their egg , or kill for their meat and/or feathers....
, is often sold as an over-the-counter therapeutic supplement. In this case, it is usually sourced from the seeds of Griffonia simplicifolia
Griffonia simplicifolia

Griffonia simplicifolia is a woody vine shrub native to West Africa and Central Africa. It grows to about 3 m, and bears greenish flowers followed by black pods....
. 5-HTP in supplement form is typically sold in 50 mg or 100 mg gelatin
Gelatin

Gelatin is a translucent, colorless, brittle, nearly tasteless solid, derived from the collagen inside animals' skin and mostly bones. It has been commonly used as a gelling agent in food, pharmaceutical, photography, and cosmetic manufacturing....
 or vegetarian capsules.

Research

A recent (2001) meta-analysis found that of 108 studies on 5-HTP published between 1966 and 2000, only two met the authors' quality standards for inclusion. The two studies that were deemed of sufficient quality did not deal with 5-HTP exclusively, instead combining results for 5-HTP and tryptophan
Tryptophan

Tryptophan is one of the 20 List of standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG....
, so the results may not be completely applicable for 5-HTP alone. While the combined analysis of the two 5-HTP and tryptophan studies showed significant effectiveness over placebo in treating depression, the authors state that overall "the evidence was of insufficient quality to be conclusive." They also state that "because alternative antidepressants exist which have been proven to be effective and safe the clinical usefulness of 5-HTP and tryptophan is limited at present."

Trp 5ht Pathway

Possible risks or side effects


Because 5-HTP has not been thoroughly studied in a clinical setting, possible side effects and interactions with other drugs are not well known.

Due to the conversion of 5-HTP into serotonin by the liver, there is a significant risk of heart valve disease from serotonin's effect on the heart. In Europe, 5-HTP is prescribed with carbidopa
Carbidopa

Carbidopa is a medication given to people with Parkinson's disease in order to inhibit peripheral metabolism of levodopa....
 to prevent the conversion of 5-HTP into serotonin until it reaches the brain.

Direct and indirect evidence for possible risks and side effects associated with 5-HTP:

In people:

  • Heart valve damage or disease.
  • When combined with MAO inhibitors, MDMA, Methylone, or other serotoninergic drugs 5-HTP may cause acute serotonin syndrome
    Serotonin syndrome

    Serotonin syndrome is a potentially life-threatening adverse drug reaction that may occur following therapeutic drug use, inadvertent interactions between drugs, overdose of particular drugs, or the recreational use of certain drugs....
    .
  • When combined with carbidopa
    Carbidopa

    Carbidopa is a medication given to people with Parkinson's disease in order to inhibit peripheral metabolism of levodopa....
     (as a treatment for symptoms of Parkinson's disease
    Parkinson's disease

    Parkinson's disease is a degenerative disorder of the central nervous system that often impairs the sufferer's motor skills and speech, as well as other functions....
    ), 5-HTP causes nausea and vomiting; however this can be alleviated via administration of granisetron
    Granisetron

    Granisetron is a serotonin 5-HT3 antagonist used as an antiemetic to treat nausea and vomiting following chemotherapy. Its main effect is to reduce the activity of the vagus nerve, which is a nerve that activates the vomiting center in the medulla oblongata....
    .


In animals:

  • In rodents, 5-HTP administration is used in various experimental procedures to induce a "head twitch response" -- behaviour generally thought to be correlated with the animal experiencing hallucinations. There is no evidence however for a similar response in humans, at least when dosage is within the recommended daily levels.
  • In rats, 5-HTP administration raises the risk of serotonin toxicity when given alongside other serotonergic drugs..
  • When given to pregnant sheep, 5-HTP alters the behavior of the fetus.


See also

  • Serotonin
    Serotonin

    Serotonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system and enterochromaffin cells in the gastrointestinal tract of animals including humans....
  • Tryptophan
    Tryptophan

    Tryptophan is one of the 20 List of standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG....
  • Vitamin B6
    Vitamin B6

    Vitamin B6 is a water-soluble vitamin and is part of the vitamin B complex group. Pyridoxal phosphate is the active form and is a cofactor in many reactions of amino acid metabolism, including transamination, deamination, and decarboxylation....
  • Pyridoxal Phosphate (PLP)
    Pyridoxal-phosphate

    Pyridoxal-phosphate is a prosthetic group of some enzymes. It is the active form of vitamin B6 which comprises three natural organic compounds, pyridoxal, pyridoxamine and pyridoxine....
     - Bioactive form of vitamin B6


Further reading


  • at Psychology Today
    Psychology Today

    Psychology Today is a bi-monthly magazine published in the United States. It is a psychology-based magazine about relationships, health and related topics written for a mass audience of non-psychologists....


  • at University of Maryland
    University of Maryland, Baltimore

    University of Maryland, Baltimore, was founded in 1807. It comprises some of the oldest professional schools in the nation and world. It is the original campus of the University System of Maryland....
     Medical Center