serotonin. Serotonin is a hormone that transmits signals between nerve cells. It also causes blood vessels to narrow. Changes in the level of serotonin in the brain can alter mood.
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myalgia syndrome (EMS) and 37 deaths. EMS is a neurological condition with symptoms that include fatigue; intense muscle pain; nerve pain; skin changes; baldness; rash; and pain and swelling affecting the joints, connective tissue, lungs, heart, and liver. Symptoms tend to improve over time, but some people may still experience symptoms up to 2 years after they develop EMS. Some people report that their symptoms have never gone away completely.
In 1990, L-tryptophan was recalled from the market due to these safety concerns. After the limitation of L-tryptophan products, the number of EMS cases dropped sharply. The exact cause of EMS in patients taking L-tryptophan is unknown, but some evidence suggests it may be due to contaminated L-tryptophan products. About 95% of all EMS cases were traced to L-tryptophan produced by a single manufacturer in Japan. Currently, under the Dietary Supplement Health and Education Act (DSHEA) of 1994, L-tryptophan is available and marketed as a dietary supplement.
L-tryptophan can cause some side effects such as heartburn, stomach pain, belching and gas, nausea, vomiting, diarrhea, and loss of appetite. It can also cause headache, lightheadedness, drowsiness, dry mouth, visual blurring, muscle weakness, and sexual problems.
Special Precautions & Warnings:Pregnancy and breast-feeding: L-tryptophan is LIKELY UNSAFE in pregnancy because it may harm the unborn child. Not enough is known about the safety of L-tryptophan during breast-feeding. Avoid using L-tryptophan during pregnancy and breast-feeding.
A white blood cell disorder called eosinophilia: L-tryptophan might make this condition worse. L-tryptophan has been associated with the development of eosinophilia-myalgia syndrome (EMS).
Liver or kidney disease: L-tryptophan might make these conditions worse since it has been associated with the development of eosinophilia-myalgia syndrome (EMS).
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.