tryptophan

noun

tryp·​to·​phan ˈtrip-tə-ˌfan 

variants or less commonly tryptophane

ˈtrip-tə-ˌfān 

: a crystalline essential amino acid C₁₁H₁₂N₂O₂ that is widely distributed in proteins

Examples of tryptophan in a Sentence

Recent Examples on the Web

Foods high in the amino acid tryptophan (like milk, turkey, chicken, lobster, and certain types of nuts) can also increase lethargy, according to Dr. Ganjhu. —Caroline Tien, SELF, 6 Aug. 2025

One-third of a medium avocado delivers 13 milligrams of tryptophan, an amino acid precursor to melatonin, the hormone that helps regulate sleep-wake cycles. —Melissa Fleur Afshar, MSNBC Newsweek, 12 June 2025

Such foods include legumes such as chickpeas, lentils, tofu, nuts, seeds and beans, which are all good sources of tryptophan, according to the book. —Madeline Holcombe, CNN Money, 23 May 2025

Some studies found that high doses of tryptophan can lessen:8 Anxiety Depression Irritability 6. —Julie Marks, Verywell Health, 19 May 2025

Word History

Etymology

borrowed from German Tryptophan, from tryptisch tryptic + -o- -o- + -phan -phane

First Known Use

1890, in the meaning defined above

Phrases Containing tryptophan

• L-tryptophan

Rhymes for tryptophan

• boffin
• coffin
• offen
• often
• soften

Kids Definition

tryptophan

noun

tryp·​to·​phan ˈtrip-tə-ˌfan 

: an amino acid that is found in many proteins and is necessary for life but cannot be manufactured by the human body and must be obtained in food

Medical Definition

tryptophan

noun

tryp·​to·​phan ˈtrip-tə-ˌfan 

variants also tryptophane

-ˌfān 

: a crystalline essential amino acid C₁₁H₁₂N₂O₂ that is widely distributed in proteins

—abbreviation Trp