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

Why These Ingredients According to Northwestern Medicine and NPR, the nutrients that matter most for sleep are tryptophan, magnesium, natural melatonin and complex carbohydrates. —Allison Palmer, Charlotte Observer, 30 Mar. 2026

What Your Bedtime Snack Needs to Do Per Carolinas Thyroid Institute and Northwestern Medicine, the ideal bedtime snack stabilizes blood sugar overnight, delivers tryptophan to support melatonin production and provides magnesium to help regulate cortisol and calm the nervous system. —Allison Palmer, Miami Herald, 30 Mar. 2026

These amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine – collectively necessary for building muscle, producing enzymes and hormones and maintaining healthy tissue. —Daryl Austin, USA Today, 21 Mar. 2026

Therefore, eating foods that are rich in tryptophan will help to encourage the production of melatonin. —Hannah Coates, Vogue, 19 Mar. 2026

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