5-hydroxytryptophan (5-HTP) is a chemical that the body makes from tryptophan (an essential amino acid, which has to be obtained through the diet). After tryptophan is converted into 5-HTP, the chemical is then converted into another chemical called serotonin (a neurotransmitter, which relays signals between brain cells). 5-HTP dietary supplements help raise serotonin levels in the brain. Since serotonin helps regulate mood and behavior, 5-HTP may have a positive effect on sleep, mood, anxiety, appetite, and pain sensation.
5-HTP is not present in the foods we eat, although tryptophan is. (Eating foods with tryptophan does not increase 5-HTP levels very much, however.) As a supplement, 5-HTP is obtained from the seeds of an African plant called Griffonia simplicifolia.
In 1989, the presence of a contaminant called Peak X was found in tryptophan supplements. Researchers believed that an outbreak of eosinophilic myalgia syndrome (EMS; a potentially fatal disorder that affects the skin, blood, muscles, and organs) could be traced to the contaminated tryptophan, and the U.S. Food and Drug Administration pulled all tryptophan supplements off the market. Since then, Peak X was also found in some 5-HTP supplements, and there have been a few reports of EMS associated with taking 5-HTP. However, the level of Peak X in 5-HTP was not high enough to cause any symptoms, unless very high doses of 5-HTP were taken. Because of this concern, however, you should talk to your doctor before taking 5-HTP, and make sure you get the supplement from a reliable manufacturer. (See "Precautions.")
5-HTP may be helpful in treating a wide variety of conditions related to low serotonin levels, including the following:
Depression
Some small studies indicate that 5-HTP may be as effective as certain antidepressant drugs in treating individuals with mild-to-moderate depression. Like the class of antidepressants known as selective serotonin reuptake inhibitors (SSRIs), which includes fluoxetine (Prozac) and sertraline (Zoloft), 5-HTP increases the levels of serotonin in the brain. One study compared the effects of 5-HTP to fluvoxamine (Luvox) in 63 people and found that those who were given 5-HTP did just as well as those who received the SSRI. In addition, those who took 5-HTP had fewer side effects than those who took Luvox. However, these studies were too small to say for sure if 5-HTP works; more and larger studies are needed.
Fibromyalgia
Three studies have suggested that 5-HTP can improve symptoms of fibromyalgia, including pain, anxiety, morning stiffness, and fatigue. Many people with fibromyalgia have low levels of serotonin, and antidepressants are commonly prescribed. Since 5-HTP, like antidepressants, raises levels of serotonin in the brain, it may be effective as well. However, it does not work for all people with fibromyalgia, and more studies are needed to understand its effect.
Insomnia
In one study, people who took 5-HTP went to sleep quicker and experienced a deeper sleep than those who took placebo.
Migraines and Headaches
Some studies suggest that high doses of 5-HTP may be effective in children and adults with various types of headaches, including migraines. However, the evidence is mixed, with other studies showing no effect.
Obesity
A few small studies have examined whether 5-HTP can help people lose weight, with encouraging results. In one study, those who took 5-HTP ate fewer calories, although they were not trying to diet, compared to those who took placebo. Researchers believe 5-HTP led people to feel more full (satiety) after eating, so they ate less. A follow-up study, which compared 5-HTP to placebo during a diet and non-diet period found that those who took 5-HTP lost about 2% of body weight during the non-diet period and another 3% when they dieted. Those taking placebo did not lose any weight. However, doses used in these studies were high, and many participants experienced side effects (nausea). If you are seriously overweight, see your doctor before taking any weight-loss aid, and remember that you will need to change your eating and exercise habits to lose more than a few pounds.
Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of your health care provider.
As mentioned previously, tryptophan use has been associated with the development of serious conditions such as liver and brain toxicity, and with eosinophilic myalgia syndrome (EMS), a potentially fatal disorder that affects the skin, blood, muscles, and organs. Such reports prompted the FDA to ban the sale of all tryptophan supplements in 1989. As with tryptophan, EMS has been reported in 10 people taking 5-HTP.
Side effects of 5-HTP are usually mild and can include nausea, heartburn, flatulence, feelings of fullness, and rumbling sensations in some people. At high doses, it is possible that serotonin syndrome, a dangerous condition caused by too much serotonin in the body, could develop. For that reason, you should talk to your doctor before taking higher-than-recommended doses.
People with high blood pressure or diabetes should talk to their doctor before taking 5-HTP.
If you take antidepressants, you should not take 5-HTP (see "Possible Interactions.").
People with liver disease, pregnant women, and nursing mothers should not take 5-HTP.
If you are currently being treated with any of the following medications, you should not use 5-HTP without first talking to your healthcare provider.
Antidepressants -- People who are taking antidepressant medications should not take 5-HTP. These medications could combine with 5-HTP to cause serotonin syndrome, a dangerous condition characterized by mental changes, hot flashes, rapidly fluctuating blood pressure and heart rate, and possibly coma. Antidepressant medications that can interact with 5-HTP include:
- SSRIs: Citalopram (Celexa), escitalopram (Lexapro), fluvoxamine (Luvox), paroxetine (Paxil), fluoxetine (Prozac), sertraline (Zoloft)
- Tricyclics: Amitriptyline (Elavil), nortryptyline (Pamelor), imipramine (Tofranil)
- Monoamine oxidase inhibitors (MAOIs): Phenelzine, (Nardil), tranylcypromine (Parnate)
- Nefazodone (Serzone)
Carbidopa -- Taking 5-HTP with carbidopa, a medication used to treat Parkinson's disease, may cause a scleroderma-like illness (a condition in which the skin becomes hard, thick, and inflamed).
Tramadol (Ultram) -- Tramadol, used for pain control and sometimes prescribed for people with fibromyalgia, may also increase serotonin levels too much if taken in combination with 5-HTP. Serotonin syndrome has been reported in some people taking the two together.
Triptans (used to treat migraines) -- 5-HTP can increase the risk of side effects, including serotonin syndrome, when taken with these medications:
- Naratriptan (Amerge)
- Rizatriptan (Maxalt)
- Sumatriptan (Imitrex)
- Zolmitriptan (Zomig)
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