What Are the Dangers of Tryptophan?

Tryptophan is an amino acid; amino acids are substances found in proteins. You need tryptophan to make new proteins; it also is needed to make other compounds in your body, such as niacin and serotonin. Although tryptophan supplements are generally safe, they can cause serious side effects.


Tryptophan is an essential amino acid, which means your body needs to get it from dietary protein sources to maintain your health. Tryptophan is important for making proteins and other substances, including serotonin, that affect the brain. Tryptophan supplements are sold over the counter as "natural" treatment for various conditions, including insomnia, depression, anxiety, attention deficit disorder and premenstrual syndrome.

Side Effects

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Tryptophan's side effects can include dizziness, drowsiness, loss of appetite, headache, dry mouth and nausea. If you are taking tryptophan supplements for the first time, avoid taking them before operating heavy machinery or engaging in any other activity that requires mental alertness. Fight dry mouth with gum or sugarless candy.


Too much tryptophan can cause additional problems. A tryptophan overdose can cause a condition known as eosiniophilia-myalgia syndrome, which can cause severe muscle pain, nerve pain, hair loss, fatigue, a rash, dry skin and high levels of a type of immune cell known as eosinophils. A tryptophan overdose can also cause serotonin syndrome, which can result in confusion, hallucinations, muscle spasms, trouble walking, increased sweating, fever, rapid heartbeat, faintness and diarrhea. There is no consensus maximum safe dose for tryptophan, so there is no set "unsafe" amount. However, MayoClinic.com recommends a dose of 8 g to 12 g per day divided into three to four doses.


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One potential hazard of consuming tryptophan and other supplements is that they are not as carefully regulated as substances classified as medications. Tryptophan supplements were banned in the United States for a time in the 1990s, because of an outbreak of eosionophilia myalgia in 1989 that may have resulted from contaminated supplements. However, changes in the way that supplements are regulated allowed tryptophan supplements to be reintroduced in 1995. Buy tryptophan supplements from a reputable manufacturer to reduce the risk of potentially toxic contaminants. Check with your doctor before taking any supplements, especially if you have health problems, and advise him of any medicines or supplements you already are taking to avoid interactions. Tryptophan supplements may not be safe for you if you are pregnant or are taking benzodiazepines, antidepressants or triptans, a class of medication often used for migraines.