tryptophan
Americannoun
noun
Etymology
Origin of tryptophan
1900–05; trypto- (irregular combining form representing Greek trīptós “rubbed”) + -phan(e) ( def. )
Explanation
Tryptophan is an amino acid that humans need in their diets in order to be healthy. Meat is known for providing lots of tryptophan. You may be familiar with tryptophan as the chemical present in turkey that is supposed to make people feel like taking a nap after their Thanksgiving feasts. In reality, scientists suspect that carbohydrates and alcohol — as well as overeating — are the true culprits in post-feast sleepiness. Tryptophan is important, though, since it helps our bodies synthesize the protein that we eat.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
To create the compounds, the researchers combined several amino acids with tryptamine, a naturally occurring metabolite derived from the essential amino acid tryptophan.
From Science Daily ● May 14, 2026
Scientists have repeatedly observed disruptions in how tryptophan is processed in aging brains, with even stronger effects seen in neurodegenerative and psychiatric disorders.
From Science Daily ● Jan. 15, 2026
Partly because I was exhausted from the tryptophan I had ingested with my turkey the day before and could not get out of bed.
From The Wall Street Journal ● Nov. 28, 2025
No—they’re football tryptophan, a snoozy bore to watch.
From The Wall Street Journal ● Nov. 24, 2025
Maize lacks digestible niacin, the amino acids lysine and tryptophan, necessary to make proteins and diets with too much maize can lead to protein deficiency and pellagra, a disease caused by lack of niacin.
From "1491" by Charles C. Mann
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