NIH MedPlus Reference Information

What is it?

5-HTP (5-Hydroxytryptophan) is a chemical by-product of the protein building block L-tryptophan. It is also produced commercially from the seeds of an African plant (Griffonia simplicifolia).

5-HTP is used for sleep disorders, depression, anxiety, migraine and tension-type headaches, fibromyalgia, binge eating associated with obesity, premenstrual syndrome (PMS), premenstrual dysphoric disorder (PMDD), attention deficit-hyperactivity disorder (ADHD), and along with prescription drugs to treat seizure disorder and Parkinson’s disease.

L-5-hydroxytryptophan (5-HTP) is the immediate precursor of serotonin. It is readily synthesized into serotonin without biochemical feedback. This nutrient has a large and strong following who advocate exaggerated and inaccurate claims relating to its effectiveness in the treatment of depression and a number of other serotonin-related diseases.

How effective is it?

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The following scientific facts are generally accepted without dispute:

  • In central nervous system disease states associated with synaptic serotonin dysfunction, synaptic serotonin levels in the brain must be increased to induce optimal outcomes.
  • Serotonin does not cross the blood–brain barrier.
  • 5-HTP freely crosses the blood–brain barrier.
  • 5-HTP is freely converted to serotonin without biochemical feedback inhibition.
  • When infinitely high amounts of 5-HTP are administered, it is theoretically possible to achieve infinitely high levels of serotonin. One limiting factor is the availability of the enzyme L-aromatic amino acid decarboxylase (AAAD), which freely catalyzes the conversion of 5-HTP to serotonin.

The basic facts listed above form the basis of a very appealing and vehemently defended scenario, “5-HTP is all that is needed when levels of serotonin need to be increased effectively and safely.” Inadequate levels of serotonin in the brain have been associated with numerous disease states and here is a nutrient that can theoretically raise serotonin levels as high as needed.

The effectiveness ratings for 5-HTP are as follows:

Possibly effective for…

  • Depression. Research shows that taking 5-HTP by mouth might improve symptoms of depression. Several trials have found that doses of 50-3000 mg daily for 2-4 weeks can improve symptoms of depression. Some early research also shows that 5-HTP might be as beneficial as conventional antidepressant therapy.
  • Fibromyalgia. Taking 5-HTP by mouth appears to improve symptoms of fibromyalgia including pain severity, morning stiffness, and sleeplessness.

Insufficient evidence to rate effectiveness for…

  • Alcoholism. Early research shows that taking 5-HTP with D-phenylalanine and L-glutamine for 40 days can reduce alcohol withdrawal symptoms. However, taking 5-HTP with carbidopa daily for one year does not seem to help people stop drinking. The effect of 5-HTP alone for alcoholism is not clear.
  • Alzheimer’s disease. Early research suggests that taking 5-HTP by mouth does not help symptoms of Alzheimer’s disease.
  • Anxiety. Evidence on the effects of 5-HTP for anxiety is unclear. Taking up to 300 mg of 5-HTP daily along with carbidopa seems to reduce anxiety symptoms in people with anxiety disorders. However, taking 60 mg of 5-HTP daily through the vein does not reduce anxiety in people with panic disorders.
  • Nervous system disorder (Cerebellar ataxia). Evidence on the use of 5-HTP for cerebellar ataxia is unclear. Early evidence shows that taking 5 mg/kg of 5-HTP daily for 4 months can decrease nervous system dysfunction. However, other research shows that taking 5-HTP daily for up to one year does not improve symptoms of cerebellar ataxia.
  • Down syndrome. Taking 2 mg/kg of 5-HTP daily for 3 years does not improve muscle movement, social skills, or intellectual development in newborn children with Down syndrome.
  • Headache. Evidence on the use of 5-HTP to prevent or treat headache symptoms is unclear. Some research shows that taking 5-HTP daily can reduce headache symptoms in children with headaches. However, other studies show that 5-HTP does not reduce the number or severity of headaches.
  • Insomnia. Taking an amino acid formula (Gabadone) containing gamma-aminobutyric acid (GABA) and 5-HTP seems to help people with sleeping problems fall asleep faster and stay asleep longer. The effect of 5-HTP alone on sleeping problems is unclear.
  • Menopausal symptoms. Taking 150 mg of 5-HTP daily for 4 weeks does not reduce hot flashes in postmenopausal women.
  • Migraine headache. Evidence on the effects of 5-HTP for the prevention or treatment of migraines in adults is unclear. Some studies show that taking 5-HTP daily does not reduce migraines, while other studies show that it might be as beneficial as prescription drugs. 5-HTP does not seem to reduce migraines in children.
  • Obesity. Early research suggests that taking 5-HTP might help reduce appetite, caloric intake, and weight in obese people.
  • Muscle spasms in the mouth (Palatal myoclonus). Early evidence suggests that taking 5-HTP by mouth might reduce muscle spasms in people with palatal myoclonus.
  • Premenstrual syndrome (PMS).
  • Premenstrual dysphoric disorder (PMDD).
  • Attention deficit-hyperactivity disorder (ADHD).
  • Other conditions.

More evidence is needed to rate the effectiveness of 5-HTP for these uses.

How does it work?

5-HTP works in the brain and central nervous system by increasing the production of the chemical serotonin. Serotonin can affect sleep, appetite, temperature, sexual behavior, and pain sensation. Since 5-HTP increases the synthesis of serotonin, it is used for several diseases where serotonin is believed to play an important role including depression, insomnia, obesity, and many other conditions.

Are there safety concerns?

5-HTP is POSSIBLY SAFE when taking by mouth. However, some people who have taken it have come down with eosinophilia-myalgia syndrome (EMS), a serious condition involving extreme muscle tenderness (myalgia) and blood abnormalities (eosinophilia). Some people think EMS might be caused by an accidental ingredient (contaminant) in some 5-HTP products. However, there is not enough scientific evidence to know if EMS is caused by 5-HTP, a contaminant, or some other factor. Until more is known, 5-HTP should be used cautiously.

Other potential side effects of 5-HTP include heartburn, stomach pain, nausea, vomiting, diarrhea, drowsiness, sexual problems, and muscle problems.

Special precautions & warnings:

Pregnancy and breast-feeding: 5-HTP is POSSIBLY UNSAFE when taken by mouth when pregnant or breast-feeding. Avoid using it.

Down syndrome: There are reports of 5-HTP causing seizures in some people with Down syndrome. In one group studied, 15% of people with Down syndrome receiving long-term 5-HTP treatment experienced seizures.

Surgery: 5-HTP can affect a brain chemical called serotonin. Some drugs administered during surgery can also affect serotonin. Taking 5-HTP before surgery might cause too much serotonin in the brain and can result in serious side effects including heart problems, shivering, and anxiety. Tell patients to stop taking 5-HTP at least 2 weeks before surgery.

Are there interactions with medications?

Do not take this combination.
Medications for depression (Antidepressant drugs)
5-HTP increases a brain chemical called serotonin. Some medications for depression also increase serotonin. Taking 5-HTP along with these medications for depression might increase serotonin too much and cause serious side effects including heart problems, shivering, and anxiety. Do not take 5-HTP if you are taking medications for depression.

Some of these medications for depression include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), amitriptyline (Elavil), clomipramine (Anafranil), imipramine (Tofranil), and others.

Medications for depression (MAOIs)
5-HTP increases a chemical in the brain. This chemical is called serotonin. Some medications used for depression also increase serotonin. Taking 5-HTP with these medications used for depression might cause there to be too much serotonin. This could cause serious side effects including heart problems, shivering, and anxiety.

Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.

Be cautious with this combination.
Carbidopa (Lodosyn)
5-HTP can affect the brain. Carbidopa (Lodosyn) can also affect the brain. Taking 5-HTP along with carbidopa can increase the risk of serious side effects including rapid speech, anxiety, aggressiveness, and others.
Dextromethorphan (Robitussin DM, and others)
5-HTP can affect a brain chemical called serotonin. Dextromethorphan (Robitussin DM, others) can also affect serotonin. Taking 5-HTP along with dextromethorphan (Robitussin DM, others) might cause too much serotonin in the brain and can result in serious side effects including heart problems, shivering, and anxiety. Do not take 5-HTP if you are taking dextromethorphan (Robitussin DM, and others).
Meperidine (Demerol)
5-HTP increases a chemical in the brain called serotonin. Meperidine (Demerol) can also increase serotonin in the brain. Taking 5-HTP along with meperidine (Demerol) might cause too much serotonin in the brain and serious side effects including heart problems, shivering, and anxiety.
Pentazocine (Talwin)
5-HTP increases a brain chemical called serotonin. Pentazocine (Talwin) also increases serotonin. Taking 5-HTP along with pentazocine (Talwin) might increase serotonin too much. This might cause serious side effects including heart problems, shivering, and anxiety. Do not take 5-HTP if you are taking pentazocine (Talwin).
Sedative medications (CNS depressants)
5-HTP might cause sleepiness and drowsiness. Medications that cause sleepiness are called sedatives. Taking 5-HTP along with sedative medications might cause too much sleepiness.

Some sedative medications include clonazepam (Klonopin), lorazepam (Ativan), phenobarbital (Donnatal), zolpidem (Ambien), and others.

Tramadol (Ultram)
5-HTP increases a brain chemical called serotonin. Tramadol (Ultram) can also increase serotonin. Taking 5-HTP along with tramadol (Ultram) might cause too much serotonin in the brain and might result in side effects including confusion, shivering, stiff muscles, and others.

Are there interactions with herbs and supplements?

Herbs and supplements with sedative properties
5-HTP can cause sleepiness or drowsiness. Using it along with other herbs and supplements that have the same effect might cause too much sleepiness. Some of these herbs and supplements include calamus, California poppy, catnip, hops, Jamaican dogwood, kava, St. John’s wort, skullcap, valerian, yerba mansa, and others.
Herbs and supplements with serotonergic properties
5-HTP increases a brain chemical called serotonin. Taking 5-HTP along with other herbs and supplements that increase serotonin might lead to too much serotonin and cause side effects including heart problems, shivering and anxiety. Other herbs and supplements that increase serotonin levels include Hawaiian baby woodrose, L-tryptophan, S-adenosylmethionine (SAMe), and St. John’s wort.

Are there interactions with foods?

There are no known interactions with foods.

What dose is used?

The appropriate dose of 5-HTP depends on several factors such as the user’s age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for 5-HTP. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

Other names

5HTP, 5 HTP, 5 Hydroxy-Tryptophan, 5 Hydroxy-Tryptophane, 5-hydroxytryptophan, 5-Hydroxytryptophane, 5-Hydroxy L-Tryptophan, 5-Hydroxy L-Tryptophane, 5-Hydroxy Tryptophan, 5-Hydroxy Tryptophane, 5-L-Hydroxytryptophan, L-5 HTP, L-5 hydroxytryptophan, L-5 Hydroxytryptophane, Oxitriptan.


To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.


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