5-Hydroxytryptophan (5-HTP) Side Effects and Benefits

5-HTP

This article reviews the benefits of 5-HTP for depression, mood disorders, insomnia, fibromyalgia, appetite
control and weight loss, and risks, toxicity and interaction with drugs and other natural antidepressants,
such as SAM-e and St. John's Wort.

Pharmacokinetics and Pharmacology
5-Hydroxytryptophan (5-HTP) is a chemical involved in mood, behavior, appetite, and sleep. In this section,
we'll discuss its absorption and how it affects our mood, appetite, sleep, depression or even our sexual
behavior.

Intestinal absorption of 5-HTP does not require a transporter, and is not affected by the presence of other
amino acids. Thus, 5-HTP is well absorbed from an oral dose, with absorption (AUC) of about 70 percent.
In addition, 5-HTP can easily cross the blood-brain barrier and effectively increases central nervous system
(CNS) synthesis of serotonin.

5 HTP Benefits - Weight Loss
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-HTP may help suppress
appetite and promote weight loss via stimulating the production of serotonin.

In some studies, 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-HTP and the conversion of L-tryptophan to 5-HTP is
inefficient, dieters usually obtain 5-HTP from supplements.

5-HTP Benefits- Depression? How does 5-HTP interact with other drugs (e.g. SSRIs)?

Several double-blind studies have shown that 5-HTP was effective in the treatment of non-drug-induced
depression. Selective serotonin reuptake inhibitors (SSRIs) are not fully effective because they affect only
serotonin reuptake. 5-HTP actually is the immediate precursor of serotonin, thus, 5-5-HTP effectively
increases central nervous system synthesis of serotonin. Combination of 5-HTP should have synergistic
effects on depression treatment. [18]

5-Hydroxytryptophan (5-HTP) SIDE EFFECTS / RISKS

In animal studies, high doses of 5-HTP caused muscle jerks and diarrhea [1-3] and injection of 5-HTP
caused kidney damage [4]. In a clinical study, high doses of 5-HTP caused nausea, headache, sleepiness,
muscle pain or anxiety.

Gendle and Golding at Elon University, North Carolina, conducted a clinical study with 5-HTP. This study
examined if oral administration of 5-HTP to 46 healthy adults (undergraduates) impacted: (1) mood states,
as measured by the Profile of Mood States (POMS); and (2) performance on the Iowa Gambling Task
(IGT), a measure sensitive to alterations in frontocortical serotonin levels. They found 5-HTP did not
significantly alter mood states, but did impair performance on the IGT. Oral 5-HTP specifically impaired
decision making under ambiguity but not under risk. Thus, oral 5-HTP is psychoactive even at low doses!
[A1]

WARNING

Because 5-HTP affects the serotonin levels, 5-HTP should not be taken together with antidepressants.
And, people suffered from liver disease may not be able to regulate 5-HTP [5].

References

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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 and carbidopa. N Engl J Med
1980;303:782?7. 6. van Praag HM et al. Monoamine precursors in the treatment of psychiatric disorders. Nutrition and the Brain, vol. 7, eds. RJ
Wurtman, JJ Wurtman. New York: Raven Press, 1986 [review]. 7. Russell IJ et al. Platelet 3H-imipramine uptake receptor density and serum
serotonin levels in patients with fibromyalgia/fibrositis syndrome. J Rheumatol 1992;19:90?4.
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Rheumatol 1997;24:555?9. 10. Kimball RW et al. Effect of serotonin in migraine patients. Neurology 1960;10:107?11.
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12. Caruso I et al. Double-blind study of 5-hydroxytryptophan versus placebo in the treatment of primary fibromyalgia syndrome. J Int Med Res
1990;18:201?9. 13. Byerley WF et al. 5-hydroxytryptophan: A review of its antidepressant efficacy and adverse effects . J Clin 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
Aug;3(4):271-80. [A1] Oral administration of 5-hydroxytryptophan (5-HTP) impairs decision making under ambiguity but not under risk: evidence
from the Iowa Gambling Task. Hum Psychopharmacol. 2010 Aug;25(6):491-9.

5-Hydroxytryptophan (5-HTP) Side Effects, Benefits, Research Studies, Safety, Toxicity, Risks, Dosage 50 mg, 100 mg, 300 mg and
overdose (Updated on June 4, 2011)