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L-Tryptophan & Anxiety

By Christy Callahan

L-tryptophan is an amino acid that has been linked to the calming effects you may feel after eating Thanksgiving turkey. L-tryptophan is a precursor to the brain chemical serotonin, which helps regulate mood and promote calm and sleep. Available as a supplement, L-tryptophan has been used to treat depression and bipolar, states You may find it helpful in reducing anxiety and inducing calm.


According to, anxiety is a general feeling of being worried. You may experience occasional anxiety, at work or other times during your day, but you may not suffer from generalized anxiety disorder, GAD. The website defines GAD as having anxiety frequently or excessively, not linked to a specific situation. GAD interferes with daily living, as the nervousness can keep you from performing at work or taking care of your personal life. Anxiety can be accompanied by muscle tension, trembling, restlessness, upset stomach, fast breathing, sweating, or lack of concentration. It can affect your sleep patterns as well, making it difficult to fall or stay asleep.


Scientists do not know the precise causes of anxiety; however, according to, they believe it may be due to imbalances in the brain chemicals, or neurotransmitters, serotonin and norpinephrine. Serotonin, biochemically known as 5-hydroxytryptamine, comes from L-tryptophan. states that serotonin is used to regulate mood and emotions, and may play a role in social anxiety disorder. Genetic composition, work, and life circumstances can also contribute to anxiety and GAD.


L-tryptophan is an amino acid that is naturally produced by the body, but is also found in chocolate, oats, bananas, dried dates, cottage cheese, red meat, fish, milk, peanuts and, most famously, turkey. According to, L-tryptophan's effects may come from its ability to cross the blood-brain barrier, BBB, and increase the body's serotonin levels. Serotonin itself, if ingested orally, cannot cross the BBB; thus in order to increase stores, precursors like L-tryptophan must be taken. lists anxiety, insomnia, depression, and PMS as uses for the amino acid; however, not all uses are approved by the FDA. Interactions between the supplement and medications can occur. Talk to your doctor before trying L-tryptophan.


Studies have found that L-tryptophan plays an important role in maintaining serotonin levels and preventing anxiety, depression and insomnia. As far back as 1969 researchers have found that the break-down of L-tryptophan into kynurenine production instead of serotonin production is linked to anxiety, insomnia and depression. These finding are discussed in an April 2010 article in the "Israel Journal of Psychiatry and Related Sciences."

The author, Dr. G.F. Oxenkrug, states that factors like stress and inflammatory substances can influence the rate of this break-down. In another study, published in the "Canadian Journal of Physiology and Pharmacology" in September 2007, L-tryptophan ingestion caused a reduction in social anxiety disorder. Researchers found that protein-sourced tryptophan, when combined with a simple carbohydrate, can help relieve anxiety.


According to, L-tryptophan can cause side effects that may impair your thinking or reactions. The site also recommends avoiding other dietary or herbal supplements to treat the same condition for which you are using L-tryptophan. Doctors do not know if L-tryptophan can harm a fetus or a breast-feeding baby; therefore, do not take if you are pregnant or breast-feeding.

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