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

Sour cherries have small amounts of melatonin and tryptophan, along with other compounds that may help improve sleep quality.26 15. —Lindsey Desoto, Health, 7 May 2025

This combination provides fiber, calcium, and tryptophan, while the cinnamon adds a touch of warming spice. —Allison Herries, Verywell Health, 28 Apr. 2025

Prenatal phthalate exposure was also linked with lower levels of the essential amino acid tryptophan, which converts into 5-hydroxytryptophan (or 5-HTP), which then turns into serotonin. —Kristen Rogers, CNN Money, 2 Apr. 2025

Since serotonin production depends on tryptophan—an amino acid obtained from food—fasting led to a deficiency, which in turn reduced serotonin levels. —Ron Estes, MSNBC Newsweek, 28 Mar. 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