Other name(s):

a-amino-b-[3-indollyl]-propionic acid

Unsubstantiated claims

Please note that this section reports on claims that have not yet been substantiated through studies.

Tryptophan may make you sleepy. It’s been used to treat insomnia. It’s also said to be a natural antidepressant and stress reducer. It may help treat hyperactivity in children. It may also treat manic episodes in people with bipolar disorder. Tryptophan also decreases appetite.

Recommended intake

The U.S. Food and Drug Administration (FDA) has prohibited sales of tryptophan. This is because it’s seen as a harmful chemical. This is because it may cause a fatal side effect. However, this is controversial. It’s recommended that no one take tryptophan as a supplement.

Side effects, toxicity, and interactions

The use of tryptophan has been associated with a potentially fatal condition. This is called eosinophilic myositis or eosinophilia-myalgia (EMS). This issue was linked to tryptophan made by a Japanese company that had recently changed its chemical processes. The cause of the condition has been hotly debated. Most experts doubt that tryptophan itself caused the problem. Instead, they think it may have been caused by something else in the compound.

Ongoing studies have found that 4,5-tryptophan-dione is the likely culprit. In a study of over-the-counter tryptophan, this contaminant was found to make up 0.5–10.3% of the samples of tryptophan. The presence of this contaminant in all samples means that tryptophan supplements aren’t safe to use.