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L-Tryptophan is an essential amino acid that the body requires to synthesize proteins and specialized molecules such as the neurotransmitter serotonin. Serotonin appears to play significant roles in sleep, emotional moods, pain control, inflammation, intestinal peristalsis, and other body functions.


Used for Amount Why
Insomnia 1 to 2 grams at bedtime L-Tryptophan has been used successfully for people with insomnia in many studies, including double-blind trials.
Pain 2 to 4 grams per day Double-blind research has also shown that oral L-tryptophan can increase tolerance to acute pain.
Premenstrual Syndrome 2 to 6 grams per day, during the second half of the menstrual cycle Some research suggests that L-tryptophan may help balance mood symptoms associated with PMS.
Depression 3 to 6 grams per day Several controlled trials have found L-tryptophan as effective as antidepressant medications. Depressed people should consult a doctor before use.
Obsessive-Compulsive Disorder 6 grams per day (only under a doctor's supervision) With a doctor's supervision, some people with OCD have experienced some symptom relief from supplementing with L-tryptophan.
Schizophrenia 1 to 8 grams per day (under a doctor's supervision) L-tryptophan supplementation has occasionally been helpful for specific schizophrenia symptoms, such as aggression and memory function.
Seasonal Affective Disorder With doctor's supervision, 2 to 4 grams per day, increasing up to 6 grams if no improvement Some research suggests that L-tryptophan alone or in combination with light therapy may improve SAD symptoms.

How to Use It
The typical Western daily diet contains 0.5 to 2.0 grams of L-tryptophan. Some authorities recommend taking L-tryptophan supplements with food or beverages high in carbohydrate and away from foods high in protein in order to improve absorption and uptake into the brain.

Where to Find It
L-Tryptophan is found in most protein-containing foods except for gelatin.

Possible Deficiencies
Disruptions in emotional well-being, including depression and anxiety, have been linked to serotonin imbalances in the brain. People with fibromyalgia often have low serotonin levels in their blood. L-Tryptophan supplements may increase serotonin synthesis in these cases. The cause of migraine headaches is related to abnormal serotonin function in blood vessels, and L-tryptophan may help correct this abnormality.

Side Effects
According to reports from clinical trials, most people tolerate L-tryptophan supplements without side effects. Occasionally, dizziness, stomach pain, and diarrhea have been reported.

Until 1989, L-tryptophan was a popular nutritional supplement used for a variety of conditions. In that year, the US Food and Drug Administration removed L-tryptophan from the over-the-counter supplement market, citing the outbreak of an unusual ailment called eosinophilia-myalgia syndrome (EMS) that was associated with its use. Since then, researchers have determined that the most likely cause of this syndrome was a contaminant produced by a single manufacturer during the process of L-tryptophan production that was not effectively removed. Contamination errors have long since been corrected, and today L-tryptophan is again available as a supplement.

Two case reports suggested that a supplement containing L-tryptophan might have caused a scleroderma-like syndrome that resembled EMS in some ways. However, the supplement in one case contained a very small amount of L-tryptophan, and it also contained other ingredients. Larger surveys of people with scleroderma have found no link with L-tryptophan supplementation, so it is likely that these two cases were either a coincidence or it could be a contamination issue.

The safety of taking L-tryptophan during pregnancy and breast-feeding is unclear. In a double-blind trial, the breathing activity of fetuses was temporarily altered when pregnant women took one gram of L-tryptophan. The relevance of that change to fetal health needs further study. In hamsters, supplementation with L-tryptophan during pregnancy decreased the litter size and increased the mortality of the offspring.

Interactions with Supplements, Foods, & Other Compounds
L-Tryptophan increases both the effectiveness and the toxicity of many antidepressant drugs, certain drugs used to treat migraines, and possibly some other drugs. Also, it is conceivable that L-tryptophan would increase the effectiveness and the toxicity of St. John's wort. To be on the safe side, people who are on any medication should consult their doctor before adding tryptophan. Also, they probably should not combine it with St. John's wort.

Copyright 2010 Aisle7. All rights reserved. Republication or redistribution of the Aisle7 content is expressly prohibited without the prior written consent of Aisle7. Healthnotes Newsletter is for educational or informational purposes only, and is not intended to diagnose or provide treatment for any condition. If you have any concerns about your own health, you should always consult with a healthcare professional. Aisle7 shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. AISLE7 is a registered trademark of Aisle7 in the United States and other jurisdictions. 

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