
5-Hydroxytryptophan (5-HTP) Side
Effects and Benefits
Intestinal absorption of 5-Hydroxytryptophan (5-HTP)
does not require a transporter, and is not affected by
the presence of other amino acids. Thus,
5-Hydroxytryptophan (5-HTP) is well absorbed from
an oral dose, with absorption (AUC) of about 70
percent. In addition, 5-Hydroxytryptophan (5-HTP) can
easily cross the blood-brain barrier and effectively
increases central nervous system (CNS) synthesis of
serotonin.
In the CNS, serotonin levels have been implicated in
the regulation of sleep, depression, anxiety,
aggression, appetite, temperature, sexual behaviour,
and pain sensation. Thus, 5-Hydroxytryptophan
(5-HTP) may help suppress appetite and promote
weight loss via stimulating the production of serotonin.
In some studies, 5-Hydroxytryptophan (5-HTP) has
been shown to have benefits in variety of conditions,
including depression, fibromyalgia, binge eating
associated with obesity, chronic headaches, and
insomnia. [12-17, 19] [6-19]
Because a typical meal contains very little amount of
5-Hydroxytryptophan (5-HTP) and the conversion of
L-tryptophan to 5-Hydroxytryptophan (5-HTP) is
inefficient, dieters usually obtain 5-Hydroxytryptophan
(5-HTP) from supplements.
ABOUT DEPRESSION
Several double-blind studies have shown
5-Hydroxytryptophan (5-HTP) to be effective in the
treatment of non-drug-induced depression. It has
been hypothesized that selective serotonin reuptake
inhibitors (SSRIs) are not fully effective because they
affect only serotonin reuptake. On the other hand,
5-Hydroxytryptophan (5-HTP) effectively increases
central nervous system synthesis of serotonin.
5-Hydroxytryptophan (5-HTP) actually is the
immediate precursor of serotonin. Thus, combination
of 5-Hydroxytryptophan (5-HTP) should have
synergistic effects on depression treatment. [18]
5-Hydroxytryptophan (5-HTP) SIDE EFFECTS
In animal studies, high doses of 5-Hydroxytryptophan
(5-HTP) caused muscle jerks and diarrhea [1-3] and
injection of 5-Hydroxytryptophan (5-HTP) caused
kidney damage [4]. In a study, high doses of
5-Hydroxytryptophan (5-HTP) caused nausea,
headache, sleepiness, muscle pain or anxiety in
some people.
Because 5-Hydroxytryptophan (5-HTP) affects the
serotonin levels, 5-Hydroxytryptophan (5-HTP) should
not be taken together with antidepressants. And,
people suffered from liver disease may not be able to
regulate 5-Hydroxytryptophan (5-HTP) [5]. As a rule,
people should consult a knowledgeable healthcare
professional before taking any supplement
References
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myoclonic jerks in guinea pigs. Eur J Pharmacol 1995;294:743?51.
2. Green AR et al. Some anticonvulsant drugs alter monoamine mediated behaviour in mice in ways similar to
electroconvulsive shock; implications for antidepressant therapy. Br J Pharmacol 1985;84:337?46.
3. Bourin M et al. 5-HTP induced diarrhea as a carcinoid syndrome model in mice? Fundam Clin Pharmacol
1996;10:450?7.
4. Hirai M et al Biochemical studies on the mechanism of difference in the renal toxicity of
5-hydroxy-L-tryptophan between Sprague Dawley and Wistar rats. J Biochem (Tokyo) 1979;86:907?13.
5. Sternberg EM et al. Development of a scleroderma-like illness during therapy with L-5-hydroxytryptophan
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Psychopharmacol 1987;7:127?37 [review].
14. Zmilacher K et al. L-5-hydroxytryptophan alone and in combination with a peripheral decarboxylase
inhibitor in the treatment of depression. Neuropsychobiology 1988;20:28?35.
15. Poldinger W et al. A functional-dimensional approach to depression: serotonin deficiency as a target
syndrome in a comparison of 5-hydroxytryptophan and fluvoxamine. Psychopathology 1991;24(2):53?81.
16. De Benedittis G, et al. 5-HT precursors in migraine prophylaxis: a double-blind cross-over study with
L-5-hydroxytryptophan versus placebo. Clin J Pain 1986;3:123?9.
17. Titus F et al. 5-hydroxytryptophan versus methysergide in the prophylaxis of migraine. Eur Neurol
1986;25:327?9.
18. Turner EH et al, 5-Hydroxytryptophan plus SSRIs for interferon-induced depression: synergistic
mechanisms for normalizing synaptic serotonin. Med Hypotheses. 2005;65(1):138-44.
19 Birdsall TC 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Altern Med Rev. 1998
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