5-Hydroxytryptophan (5-HTP)


5-HTP is the immediate precursor of the neurotransmitter serotonin. The essential amino acid tryptophan is converted to 5-HTP, which is then converted to serotonin. After the FDA removed tryptophan from the marketplace in 1989, 5-HTP became known as the easiest and most effective nutritional supplement to enhance serotonin synthesis for the treatment of depression and sleep disorders. Commercial 5-HTP is not derived from tryptophan, but rather is an extract from the seed of a plant known as Griffonia simplicifolia.

Dosage Info

Dosage Range

25-300mg daily.

Most Common Dosage

100mg daily.

Dosage Forms

Capsules and tablets.

Adult RDI

None established

Adult ODA

None established


  • None established:

Interactions and Depletions


Active Forms

5-hydroxytryptophan (5-HTP).


5-HTP is readily absorbed in the small intestine.

Toxicities & Precautions


Individuals who are already taking antidepressant medications should not begin taking 5-HTP without adequate medical supervision. Concurrent use may result in additive effects. (1)

Side Effects

Occasional side effects reported with the use of 5-HTP include nausea, vomiting, and diarrhea. (2) If any of these problems occur, they can usually be minimized by backing off to a lower dose, and then gradually increasing the dosage. Taking the supplement with meals may also help.

Functions in the Body


5-HTP is the immediate precursor for serotonin, which is a neurotransmitter that regulates moods and emotions.

Melatonin Synthesis

5-HTP is also the precursor for melatonin, which is synthesized from serotonin.


Administration of 5-HTP to patients with either migraines or tension headaches resulted in higher levels of plasma and mononuclear cell beta-endorphin, which may provide an explanation for 5-HTP’s analgesic effects in patients with headaches. (3)

Clinical Applications


In a double-blind study, obese patients receiving 5-HTP experienced early satiety, reduced carbohydrate intake, and significant weight loss. The authors state that 5-HTP may be safely used to treat obesity. (4)


71 percent of patients treated with 5-HTP experienced significant improvement. 5-HTP was more effective at reducing the intensity and duration rather than the frequency of the attacks with only minor side effects. The authors state that 5-HTP could be a treatment of choice in the prophylaxis of migraine. (5) Results from a long-term prospective study suggests that 5-HTP produces beneficial changes in the underlying central nervous system (CNS) abnormalities that are associated with migraine headaches. (6)


A group of patients diagnosed with anxiety syndromes were treated with 5-HTP in conjunction with carbodopa. A significant reduction in anxiety was observed on three different anxiety scales.


The authors of one double-blind study called 5-HTP moderately effective and remarkably safe, with 48 percent of patients experiencing greater than 50 percent reduction in frequency and severity of headaches. (7) In a study with children who experienced recurrent headaches those treated with 5-HTP experienced a 70% reduction in the frequency of headaches compared to a 11% reduction in the placebo control group. (8) In another study lasting for 8 weeks, there was no statistical difference in frequency or severity of headaches between individuals in the 5HTP and the placebo group. However, in the 2 weeks following treatment, the patients who had been treated with 5-HTP had a significant reduction in the use of analgesics and a corresponding reduction in the number of days with headaches. (9)

Sleep Disorders

5-HTP stimulates the production of melatonin. (10) In one study, patients suffering from mild insomnia experienced significant improvement taking 100mg of 5-HTP before bedtime. (11)


One type of depression is characterized by a deficiency of serotonin.In these individuals, 5-HTP decreased the incidence of depressive episodes. (12) Compared to SSRIs, 5-HTP was found to be as effective as fluvoxamine, yet 5-HTP produced significantly fewer and less severe side effects. (13) Several studies have reported 5-HTP to be as effective as tricyclic antidepressants. (14) , (15) , (16)


In a double-blind, placebo-controlled trial, fibromyalgia patients treated with 5-HTP registered significant improvements in all of the clinical parameters that were studied. (17) In another study, 50 percent of the patients experienced ‘fair’ to ‘good’ improvements in the number of tender points, anxiety, pain intensity, quality of sleep, and fatigue. (18)

Symptoms and Causes of Deficiency

Since humans can synthesize 5-HTP, there is no deficiency condition directly associated with it. Diets low in tryptophan will result in reduced production of serotonin and melatonin, which can cause depression and sleep disturbances.

Dietary Sources

5-HTP does not occur in foods. However, foods containing high levels of tryptophan will promote the synthesis of 5-HTP. High tryptophan-containing foods include meats (beef, pork, lamb, and wild game), poultry (chicken and turkey), seafood (tuna, salmon, halibut, and shrimp), cottage cheese, Swiss cheese, peanuts, cashews, and avocado.


  1. View Abstract: Dreshfield-Ahmad LJ. Enhancement in extracellular serotonin levels by 5-hydroxytryptophan loading after administration of WAY 100635 and fluoxetine. Life Sci. 2000;66(21):2035-41.
  2. View Abstract: van Vliet IM, et al. Behavioral, neuroendocrine and biochemical effects of different doses of 5-HTP in panic disorder. Eur Neuropsychopharmacol. May1996;6(2):103-10.
  3. View Abstract: Battistella PA, Bordin A, Cernetti R, et al. beta-endorphin in plasma and monocytes in juvenile headache. Headache. Feb1996;36(2):91-4.
  4. View Abstract: Cangiano C, et al. Eating Behavior and Adherence to Dietary Prescriptions in Obese Adult Subjects Treated with 5-hydroxytryptophan. Am J Clin Nutr. Nov1992;56(5):863-67.
  5. View Abstract: Titus F, et al. 5-Hydroxytryptophan versus Methysergide in the Prophylaxis of Migraine. Randomized Clinical Trial. Eur Neurol. 1986;25(5):327-29.
  6. View Abstract: Nicolodi M, Sicuteri F. L-5-hydroxytryptophan can prevent nociceptive disorders in man. Adv Exp Med Biol. 1999;467:177-82.
  7. View Abstract: De Benedittis G, et al. Serotonin Precursors in Chronic Primary Headache. A Double-blind Cross-over Study with L-5-hydroxytryptophan vs. Placebo. J Neurosurg Sci. Jul1985;29(3):239-48.
  8. View Abstract: De Giorgis G, Miletto R, Iannuccelli M, et al. Headache in association with sleep disorders in children: a psychodiagnostic evaluation and controlled clinical study-L-5-HTP versus placebo. Drugs Exp Clin Res. 1987;13:425-433.
  9. View Abstract: Ribeiro CA. L-5-Hydroxytryptophan in the prophylaxis of chronic tension-type headache: a double-blind, randomized, placebo-controlled study. For the Portuguese Head Society. Headache. Jun2000;40(6):451-6.
  10. View Abstract: den Boer JA, et al. Behavioral, Neuroendocrine, and Biochemical Effects of 5-hydroxytryptophan Administration in Panic Disorder. Psychiatry Res. Mar1990;31(3):267-78.
  11. Soulairac A, et al. Effect of 5-hydroxytryptophan, a Serotonin Precursor, on Sleep Disorders. Ann Med Psychol. Paris. 1977;1(5):792-98.
  12. View Abstract: van Praag H, et al. Depression Vulnerability and 5-hydroxytryptophan prophylaxis. Psychiatry Res. Sep1980;3(1):75-83.
  13. View Abstract: 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.
  14. van Praag HM, et al. 5-hydroxytryptophan in Combination with Clomipramine in Therapy-resistant Depression. Psychopharmacology. 1974;38:267-69.
  15. View Abstract: Nardini M, et al. Treatment of Depression with L-5-hydroxytryptophan Combined with Chlorimipramine: A Double-blind Study. Int J Clin Pharmacol Res. 1983;3(4):239-50.
  16. View Abstract: Angst J, et al. The Treatment of Depression with L-5-hydroxytryptophan versus Imipramine. Results of Two Open and One Double-blind Study. Arch Psychiatr Nervenkr. Oct1977;224(2):175-86.
  17. View Abstract: Cruso I, et al. Double-blind Study of 5-hydroxytryptophan versus Placebo in the Treatment of Primary Fibromyalgia Syndrome. J Int Med Res. May1990;18(3):201-09.
  18. View Abstract: Puttini PS, et al. Primary Fibromyalgia Syndrome and 5-hydroxy-L-tryptophan: A 90-day Open Study. J Int Med Res. Apr1992;20(2):182-89.