What Is It?
Health Benefits
Dosage Information
Guidelines for Use
General Interaction
Possible Side Effects

Evidence Based Rating Scale

What Is It?

The nutrient 5-HTP (the common name for the compound 5-hydroxytryptophan) is a derivative of the amino acid tryptophan. A mood-enhancing chemical, 5-HTP has attracted a good deal of attention because of its ability to increase pain tolerance, induce sleep, and affect how hunger is perceived. Unlike many other supplements (and drugs) that have molecules too large to pass from the bloodstream into the brain, molecules of 5-HTP are small enough to do so. Studies have shown that about 70 percent of an oral dose of 5-HTP is absorbed systemically and available to the brain. Once in the brain, 5-HTP molecules are converted into an important nervous system chemical, or Neurotransmitter, called Serotonin. The remaining 30 percent is metabolized by intestinal cells, which may be involved in communications between the gut and the brain. (1, 2)

The body produces its own supply of 5-HTP from tryptophan, an amino acid found in high-Protein foods such as chicken, fish, beef, and dairy products. Any healthy diet should include tryptophan-rich sources such as these. (Turkey is particularly high: post-Thanksgiving dinner somnolence is often attributed to its tryptophan content.) In addition, 5-HTP is available as a supplement; this form of the compound is extracted from the seeds of the African plant, Griffonia simplicifolia.

Concerns about the safety and effectiveness of 5-HTP have been raised because of its close chemical association to L-tryptophan, a supplement once embroiled in controversy and now banned from the U.S. market. In the late 1980s, the use of L-tryptophan was linked to thousands of cases of illness and more than 30 deaths. Investigators determined that impurities in the manufacturing of L-tryptophan were the likely cause of these problems, not the L-tryptophan itself. In 1994, 5-HTP was introduced in the U.S.; unlike L-tryptophan the newer compound is produced without the help of bacteria. Therefore, 5-HTP is thought to pose significantly less risk of contamination than L-tryptophan. Still, some experts continue to be concerned about impurities, and suggest avoiding high doses (700 to 900 mg a day) of 5-HTP. (Also see Cautions at the end of this article.)

Health Benefits

Europeans have been taking 5-HTP for decades to treat insomnia and depression. And promising research indicates that 5-HTP may have a beneficial effect on a broad scope of complaints, including anxiety, depression, sleep disorders, obesity, fibromyalgia, and headaches--both migraine and tension types.

Specifically, 5-HTP may help to:

  • Elevate mood in cases of depression, anxiety, and panic attacks. 5-HTP is a precursor to serotonin in the brain. Low levels of this brain neurotransmitter have been linked to depression; 5-HTP may help to elevate mood in patients with depression, anxiety or panic attacks. In addition to increasing serotonin levels, 5-HTP also seems to enhance endorphin levels, which results in pain relief and mood elevation. Since the 1970s, several clinical studies, particularly in Japan, have focused on 5-HTP for treating depression. In the first study done in Japan in 1972, 107 patients with either unipolar depression or manic bipolar depression received doses ranging from 50 to 300 mg of 5-HTP daily. Within two weeks, more than half of the patients showed a response; 74 of the patients either experienced complete relief or were significantly improved, and none experienced significant side effects. (3) In two subsequent Japanese studies, 5-HTP was shown to be effective in some patients (50 percent in one study, 35 percent in the other) who had not responded positively to any other antidepressant agent. (4, 5)

    The most detailed of the Japanese studies was conducted in 1978, enrolling 59 patients with depression: 30 male and 29 female, each group including unipolar, bipolar and other subcategories of depression, most often moderate to severe cases. Patients received 5-HTP in doses of 50 or 100 mg three times daily for at least three weeks. A total of 40 patients responded to treatment--32 of them within two weeks of treatment. Antidepressant activity and clinical effectiveness of 5-HTP was determined using the Clinical Psychopharmacology Research Group rating scale. The results indicted that 5-HTP was helpful in 14 out of 17 patients with unipolar depression, 12 out of 21 patients with bipolar depression, and 14 out of 21 with other types of depression. The degree of improvement in most cases ranged from very good to excellent. (6) Nausea is a common side-effect (several popular anti-nausea drugs actually act by blocking 5-HTP receptors in the gut); however, only 10 percent of those taking 300 mg or less of 5-HTP daily experienced nausea, compared with about 23 percent of those taking Prozac.

    Additional studies have found taking 5-HTP may improve symptoms of depression as effectively as conventional antidepressants. A 1981 review of head-to-head comparison studies showed that 5-HTP, at a dosage of 200 mg/day, improved symptoms of depression as well as tricyclic antidepressant drugs. (7) In 1987, another review called for the evaluation of the effectiveness of 5-HTP in comparison to a new breed of antidepressant drugs, the selective serotonin reuptake inhibitors (SSRIs) like Prozac, Paxil, and Zoloft. (8) In 1991, a double-blind study in Switzerland compared 5-HTP with the SSRI fluvoxamine (Luvox), which is primarily used to treat the form of anxiety known as obsessive compulsive disorder (OCD). In the study, 34 patients received 100 mg of 5-HTP and 29 patients received 50 mg of fluvoxamine three times daily for six weeks, and all were evaluated with the Hamilton Depression Scale (HDS). 5-HTP was faster acting than fluvoxamine, and a greater percentage of patients responded to 5-HTP than to fluvoxamine. Specifically, 5-HTP produced higher percentages of reductions than fluvoxamine in all subcategories of the HDS: depressed mood, anxiety, physical symptoms, and insomnia. Researchers determined 5-HTP is equal to or better than standard antidepressant drugs, with less severe side effects than conventional medication. (9) However, a 2002 Cochrane Database review of trials comparing 5-HTP or tryptophan to traditional antidepressants found only two trials (out of 108 available) were of sufficient scientific quality for inclusion in the review. The two included trials, which involved 64 patients, did indicate that 5-HTP was better than placebo at alleviating symptoms of depression. (10) 

    While many of these studies of depressed individuals included the ability of 5-HTP to relieve anxiety and panic attacks, a few other studies actually focused on this specific area. Panic attacks are more likely to occur when the availability of serotonin in the brain is low. Therefore, 5-HTP’s ability to increase serotonin levels may inhibit the panic response. In a 2002 study of 48 subjects (24 with panic disorder and 24 healthy individuals), who received either 200 mg of 5-HTP or placebo before a carbon dioxide-induced panic challenge, 5-HTP compared to placebo significantly reduced panic disorder patients' reaction to the panic challenge in measures of subjective anxiety, panic symptom score, and number of panic attacks. No similar effects were seen in healthy volunteers.  (11) 

  • Treat insomnia. Several elements of a good night's sleep appear to be influenced by 5-HTP. In addition to reducing the amount of time it takes to nod off, this compound actually may enhance the quality of sleep itself, increasing both the duration of dream states (REM sleep) and of deep slumber. Several studies in the 1970s showed results indicating 5-HTP was a viable treatment for promoting and maintaining sleep and sense of feeling rested upon waking in both normal and insomniac subjects. (12-17) Some of those studies have shown the key benefit of 5-HTP – increasing the quality of sleep – occurs by increasing REM sleep by about 25 percent while simultaneously increasing deep sleep stages 3 and 4 without increasing total sleep time. To compensate for the increase in these deep sleep stages, non-REM stages 1 and 2, the least important stages of sleep, are reduced. (15, 16) In one of the studies, sleep quality was evaluated in a group of alcoholics receiving either 200 mg or 600 mg of 5-HTP daily. The group taking 200 mg daily increased REM sleep time by 15.5 minutes during the five-night study, and the group taking 600 mg increased REM sleep time by an average of 20 minutes during the study. Dream time increased by three to four minutes a night. Although the higher dosage led to longer REM sleep, the lower dosage is sufficient in most cases. Taking too much 5-HTP may increase sleep to an abnormal level, lead to an increased risk for nightmares, and cause mild nausea. (15) 

  • Promote weight loss. Serotonin levels seem to play an important role in appetite and, thus, weight control. A diet low in tryptophan seems to lead to low brain serotonin levels, which in turn results in the brain sensing starvation and stimulating the appetite. The role of 5-HTP in increasing serotonin levels creates a feeling of satiety, which may lead to curbed appetite and, consequently, weight loss. The earliest animal studies in this area demonstrated that giving 5-HTP to rats genetically bred to overeat and be obese resulted in significant reduction in food intake. These rats had decreased activity of an enzyme that converts tryptophan to 5-HTP and subsequently to serotonin. (18) This led researchers to further investigate 5-HTP’s role as a weight loss aid for humans. Some studies indicate that when taken before meals, 5-HTP may lead to a more rapid feeling of satiety. In a 1989 Italian study of 19 overweight females with a body mass index (bmi) between 30 and 40, the women received either 8 mg of 5-HTP per kg of body weight or placebo before meals for five weeks. No dietary restrictions were prescribed so that researchers could evaluate the effect of 5-HTP in reducing appetite and promoting weight loss without any conscious effort to prohibit certain foods. The average amount of weight loss during the 5-week period of 5-HTP supplementation was a little more than 3 pounds, compared with less than 1 pound of total weight loss during the placebo period. The women taking 5-HTP felt full faster than those taking placebo and, as a result, dramatically reduced caloric intake. (19) Subsequent studies restricted the subjects to specific dietary recommendations. In a double-blind study in 1991 also in Italy, 14 overweight females with a body mass index between 30 and 40 and a tendency to overeat, received either 300 mg of 5-HTP or placebo 30 minutes before meals for a 12-week study. During the firsts six weeks there were no dietary recommendations, but during the second six-weeks the women were placed on a 1,200-calorie diet. Women receiving 5-HTP treatment collectively lost more than 10 pounds, while the women taking placebo lost slightly more than two pounds; and all women taking 5-HTP reported feeling satiated faster than those taking placebo. (20) However, some women receiving treatment reported some aversion to meat or altered taste and smell, and most experienced mild nausea during the first six weeks of the trial which abated in the last six weeks. In a 1992 trial similarly designed by the same lead author and evaluating 28 overweight subjects with dietary restrictions during the second six-week period, those receiving 300 mg of 5-HTP before each meal lost significantly more weight than those taking placebo. Those taking placebo had trouble adhering to the restricted diet. By contrast, 100 percent of subjects in the treatment group reported early satiety during the first six-week period and 90 percent reported the same during the second six-week period, thereby adhering to the restricted diet and reducing caloric intake. (21)

    In addition, because 5-HTP reportedly reduces cravings for sweets and starches, it may also be of use in helping diabetics adhere to a healthy diet. In a 1998 double-blind, placebo-controlled, randomized Italian study by the same lead author as the above studies, 25 overweight non-insulin dependent diabetic outpatients received either 750 mg of 5-HTP daily or placebo for two consecutive weeks with no dietary restrictions. Results here also indicated that patients receiving 5-HTP significantly decreased their daily energy intake, by reducing carbohydrate and fat intake, and reduced their body weight. (22)

  • Ease migraine pain. Migraine headaches have been linked to low serotonin levels. Studies are ongoing to determine if 5-HTP can help to reduce the intensity, frequency, and duration of this extremely painful type of headache by boosting the brain's serotonin levels. The supplement also may ease pain from migraine headaches by boosting the endorphin system. Several studies have indicated 5-HTP may prevent migraine headaches, which makes it preferable to conventional medications that often have significant side effects. For example, several studies have compared 5-HTP to one of the most commonly used drugs, methysergide (Sansert)  In 1986, one of the largest double-blind studies in this area evaluated 124 migraine sufferers for six months. The patients received either 600 mg of 5-HTP daily or 3 mg methysergide daily. While 75 percent of patients taking methysergide and 71 percent of patients taking 5-HTP demonstrated significant improvement in the frequency or the number of severe migraine attacks, the most important difference between groups was demonstrated in the side effects. Those in the methysergide group experienced side effects more frequently than in the 5-HTP group, and five patients in the methysergide group had to withdraw during the trial because of the side effects. (23)

    Two further studies comparing 5-HTP with conventional medications also demonstrated that 5-HTP was comparable in effectiveness in improving mood and relieving depression, and 5-HTP exceeded conventional medications in being well tolerated at doses as high as 600 mg daily. (4, 25) More recently, a 2005 German review of evidence-based medicines for migraine prevention calls 5-HTP “the most innovative development” because it has been shown to relieve migraine attacks in less than one hour. (26) Research with tension headaches is less compelling. A 2000 Portuguese double-blind, randomized, placebo-controlled study of 78 patients with chronic tension headaches receiving either 300 mg of 5-HTP or placebo for eight weeks found treatment did not reduce pain intensity or the number of days with headache. However the treatment group used fewer additional analgesics and in the two weeks post-treatment the 5-HTP group had fewer headache days. (27)

  • Increase tolerance to the pain of fibromyalgia. People who suffer from fibromyalgia, a chronic condition that commonly causes muscle pain and disabling fatigue, may have low serotonin levels. By increasing the level of these neurochemicals, 5-HTP may improve pain tolerance. However, little research has been done in the use of 5-HTP in treating fibromyalgia. A 1990 double-blind study in 50 patients with fibromyalgia found that 100 mg of 5-HTP three times daily significantly improved symptoms such as number of painful areas, morning stiffness, sleep patterns, anxiety and fatigue. The supplement also was rated by subjects and evaluating physicians as substantially better than placebo. (28) In a 1992 open study, 50 patients who received 100 mg of 5-HTP three times daily for 90-days reported significant improvement in number of tender points, anxiety, pain intensity, quality of sleep and fatigue within 30 days. (29) Further, a 1996 analytical review of 24 controlled clinical trials for fibromyalgia found the sedative effects of 5-HTP provide one of the primary benefits of supplementation for patients with fibromyalgia, which is characterized by reduced REM sleep and an increase in non-REM sleep. Because deeper levels of sleep are not achieved in fibromyalgia, sufferers wake up feeling fatigued and in pain. Taking 5-HTP may help combat these symptoms. (30) 


  • tablet
  • capsule

Dosage Information

  • For depression, anxiety, and panic attacks: Take 50 to 100 mg three times a day.
  • For insomnia: Take 100 mg 30 minutes before going to bed.
  • For weight control: Take 100 mg three times a day, 20 to 30 minutes before meals. After two weeks, increase the dose to 200 mg three times a day.
  • For migraine prevention: Work gradually up to a dosage that controls migraine pain ultimately exceeding no more than 100 mg three times a day. It may take several months to get the full benefit of 5-HTP's migraine-preventive effects.
  • For fibromyalgia: Take l00 mg three times a day. If drowsiness occurs, reduce the dose to 50 mg three times a day. 

Be sure to check out our Dosage Recommendations Chart for 5-HTP, which lists therapeutic dosages for specific ailments at a glance.

Guidelines for Use

In general, to minimize the risk for side effects, begin with a low dose of 5-HTP (50 mg once a day). Continue for one week and then increase the amount by 50 mg increments each week, up to the dose recommended for your condition. 

  • Take 5-HTP on an empty stomach for quickest absorption.
  • Don't take 5-HTP for more than three consecutive months without consulting your doctor.
  • The time it takes for an improvement in depression, anxiety, and panic attacks to develop varies among individuals. In general, however, it may take two to four weeks for a clinical response to occur.
  • If you're already taking a conventional antidepressant, such as Prozac, Wellbutrin, or Effexor, check with your doctor before starting on 5-HTP.
  • Read ingredient labels carefully; some 5-HTP supplements contain unnecessary herbs or nutrients.

 General Interaction

The combination of 5-HTP with conventional antidepressants, such as Prozac, Wellbutrin, or Effexor, may cause such unwanted reactions as anxiety, confusion, increased heart rate, excessive perspiration, and diarrhea. 

  • Don't try 5-HTP within four weeks of using an MAO inhibitor.
  • Consult your doctor before combining 5-HTP with the Herb St. John's wort.
  • Avoid taking 5-HTP with sedating antihistamines; the combination can lead to drowsiness.
  • Don't take 5-HTP with over-the-counter cold remedies or any medications containing ephedrine or pseudoephedrine, because anxiety, confusion, or other serious side effects may develop.
  • Muscle relaxants could cause excessive drowsiness when combined with 5-HTP.
  • Drowsiness may develop if 5-HTP is taken with a narcotic pain reliever such as codeine or morphine.
  • Consult your doctor before trying 5-HTP if you take levodopa for Parkinson's disease, because anxiety, confusion, or other adverse reactions may occur when the two substances are combined.
  • Psychiatric medications such as buspirone ((BuSpar) to combat anxiety) and lithium (to prevent mania in OCD) may combine with 5-HTP in such a way that anxiety, confusion, or other serious side effects develop.

 For information on interactions with specific generic drugs, see our WholeHealthMD Drug/Nutrient Interactions Chart.

Possible Side Effects

  • Side effects are typically mild but may include abdominal gas or cramping, nausea, diarrhea or constipation, insomnia, headache, palpitations, drowsiness, or a decreased sex drive.
  • Nausea, should it occur, commonly disappears after a few days.


  • Eosinophilia-myalgia syndrome (EMS) occurred in more than 1500 people prior to 1998. Symptoms include joint aches, rash, cough or difficulty breathing, edema, elevated liver function tests, and nerve abnormalities. At least 27 people died and almost all cases had consumed tryptophan from one manufacturer. Many experts consider 5-HTP supplements to be very safe. 5-HTP has not been associated with the same level of risk; however several cases of EMS-like syndromes have been reported in people taking 5-HTP, and contaminants similar to those in tryptophan have been found in some over the counter samples of 5-HTP. If you choose to take 5-HTP, be sure to get yours from a reliable source. 
  • Reduce the dose if drowsiness occurs. Also, because of this risk for drowsiness, avoid driving or performing any other potentially dangerous task until you've determined how the supplement (at various dosages) affects you.
  • Stop taking 5-HTP and call your doctor if you develop an adverse reaction to it.


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9. Poldinger W, Calanchini B, Schwarz W. A functional-dimensional approach to depression: serotonin deficiency as a target syndrome in a comparison of 5-hydroxytryptophan and fluvoxamine. Psychopathology. 1991;24:53-81.
10. Shaw K, Turner J, Del Mar C. Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database Syst Rev. 2002;(1):CD003198.
11. Schruers K, van Diest R, Overbeek T, Griez E. Acute L-5-hydroxytryptophan administration inhibits carbon dioxide-induced panic in panic disorder patients. Psychiatry Res. 2002;113:237-243.
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14. Autret A, Minz M, Bussel B, et al. Human sleep and 5-HTP. Effects of repeated high doses and of association with benserazide. Electroencephalogr Clin Neurophysiol. 1976;41:408-13.
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Date Published: 04/18/2005
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