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The acronym for 5-hydroxytryptophan (or 5-hydroxy-L-tryptophan) is 5-HTP, a compound found primarily in the brain. This compound is made from tryptophan, a natural amino acid inherent in foods. Tryptophan is an essential amino acid, which means that it cannot be made by the body. It must be obtained from food, particularly proteins. In the liver and brain, 5-HTP is converted to an important monoamine neurotransmitter called serotonin. Neurotransmitters are chemical messengers that transmit signals between neurons (nerve cells) in the brain.

Taking 5-HTP increases the body's supply of the compound, which leads to higher serotonin levels in the brain. Serotonin, also called 5-hydroxytryptamine or 5-HT, plays an important role in controlling behavior and moods. It influences many normal brain activities and also regulates the activity of other neurotransmitters. Having adequate levels of serotonin instills a feeling of relaxation , calmness, and mild euphoria (extreme happiness). Low levels of serotonin, serotonin deficiency syndrome, leads to depression, anxiety , irritability, insomnia , and many other problems.

Conditions associated with low levels of serotonin include:

This compound has other effects on the body. It is an antioxidant that protects the body from damage by substances called free radicals (unstable, toxic molecules). In this role, 5-HTP may help slow the aging process and protect the body from illness. Because serotonin is used to make melatonin , taking 5-HTP may help achieve some of the same benefits as melatonin, such as treating jet lag , depression, and insomnia. There is some evidence that 5-HTP can replenish the supply of the pain-relieving molecules called endorphins. Studies have shown that low levels of endorphins are associated with chronic fatigue syndrome , fibromyalgia, stress , and depression. In addition, 5-HTP affects other neurotransmitters, including norepinephrine and dopamine.

General use

In studies, 5-HTP has been proven effective in the treatment of carbohydrate cravings and binge eating, chronic headaches, depression, fibromyalgia, insomnia, anxiety, and panic disorders.

Most of the clinical research with 5-HTP focuses on the treatment of depression. In 15 separate studies, 5-HTP was tested on a total of 511 patients with different kinds of depression. Over half (56%) of these patients had significant improvement in depression while taking 5-HTP. The compound was found to be as effective as the selective serotonin reuptake inhibitor (SSRI) fluvoxamine and the tricyclic antidepressants, chloripramine and imipramine. Most of these studies used relatively high doses ranging from 503,250 mg daily.

Three clinical studies have found that 5-HTP can significantly improve the pain , anxiety, morning stiffness, and fatigue associated with fibromyalgia. The doses ranged from 300400 mg daily. In one study, 5-HTP treatment was as effective as a tricyclic antidepressant (amitriptyline) and monamine oxidase inhibitors (MAOI; pargilyne or phenelzine).

Three clinical studies have found that 5-HTP use led to decreased intake of food, and subsequent weight loss in obese patients. The dose used in one study was 900 mg daily, which initially caused nausea in 80% of the patients.

A few clinical trials have found that 5-HTP can effectively prevent chronic headaches, including migraine headache and tension headache . In addition, 5-HTP compared favorably with propranolol and methysergide, drugs commonly used to prevent migraines.

In treating insomnia, 5-HTP is effective because it increases the length of rapid eye movement (REM) sleep, which improves sleep quality.

The symptoms of anxiety may be significantly reduced by 5-HTP. In studies, it instilled a sense of relief in patients with panic disorders.

Other conditions that may be treated with 5-HTP, but for which no studies exist, include chronic fatigue syndrome, premenstrual syndrome, Parkinson's disease , and seizure disorders (such as epilepsy).

Although 5-HTP may be a useful alternative to conventional antidepressant drugs, one study indicated that it may be of no value for patients who have failed to respond to traditional drugs. In this study, patients who failed to respond to tricyclic antidepressants were treated with either 5-HTP or a monoamine oxidase inhibitor (MAO-I). Half of the patients improved with the MAO-I treatment, while none showed any benefit from 5-HTP treatment.


The 5-HTP preparation that is available commercially is isolated from the seed of an African plant called Griffonia simplicifolia. It is available as an enteric coated tablet, which does not break down until it reaches the intestine.

The recommended starting dose for headaches, weight loss, depression, and fibromyalgia is 50 mg three times daily. It can be taken with food. However, for weight loss it should be taken 20 minutes before eating. If it is not effective after two weeks, the dose may be increased to 100 mg three times daily, but only with the recommendation of a physician. Insomnia is treated with 25 mg (which may be increased to 100 mg after a few days) taken 30-45 minutes before bedtime.


The Mayo Clinic detected, and the U. S. Federal Drug Administration (FDA) confirmed, the presence of a contaminant (peak X) in 5-HTP produced by six different manufacturers. This contaminant is similar to one found in L-tryptophan, which in 1989 caused the potentially fatal eosinophilia myalgia syndrome (EMS) in some persons. The L-tryptophan supplements were subsequently banned by the FDA. There have been 10 reports of EMS associated with 5-HTP use. The 5-HTP contaminant was not at levels high enough to cause illness. However, taking excessive doses of 5-HTP may lead to toxic levels of peak X.

Long term studies on the safety of 5-HTP use have not been conducted. To be safe, 5-HTP should be considered a short-term remedy.

Pregnant women should not take 5-HTP because there are no clinical studies on the compound's use among this population.

Side effects

Side effects associated with 5-HTP are rare but may include headaches, mild stomachaches , nausea, nasal congestion, and constipation . There are anecdotal reports that taking high doses of 5-HTP causes nightmares or vivid dreams. Side effects may be minimized by starting with a low dose of 5-HTP and taking it with food.


It is theorized that the effectiveness of 5-HTP may be enhanced by taking vitamin B6 and niacinamide. The action of 5-HTP may be enhanced by extracts of ginger, passionflower (Passiflora incarnata ), St. John's wort, and Ginkgo biloba.

Dopa-decarbolylase inhibitors, such as carbidopa or benserazide block the enzyme that is responsible for the destruction of dopamine. However, a study by the Massachusetts College of Pharmacy and Health Sciences demonstrated that 5-HTP reaches the brain without the use of a dopa-decarboxylase inhibitor, and will produce the benefits of stress reduction and reduced food intake even when used alone.

There is a chance of developing serotonin syndrome when taking 5-HTP with an antidepressant drug. Serotonin syndrome was seen in patients taking high doses (greater than 1,200 mg daily) of L-tryptophan and MAO inhibitors. Combining 5-HTP with an MAOI or selective serotonin reuptake inhibitor antidepressant should be done with caution, under the supervision of a physician.



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Serotonin Deficiency Foundation (SDF). P.O. Box 751390, Petaluma, CA 94975-1390. (800) 976-2783.

Belinda Rowland

Samuel Uretsky, Pharm.D.