cit·​rul·​line | \ ˈsi-trə-ˌlēn How to pronounce citrulline (audio) \

Definition of citrulline

: a crystalline amino acid C6H13N3O3 formed especially as an intermediate in the conversion of ornithine to arginine

Examples of citrulline in a Sentence

Recent Examples on the Web Research is limited on the benefits of nitric oxide in physical performance, but one piece of evidence suggests supplements with L-citrulline and other vasodilators can increase the amount of nutrients transported to muscle groups. Zee Krstic, Good Housekeeping, 29 Aug. 2021 Research also shows that L-citrulline may improve muscle oxygenation and athletic performance during endurance exercise. Cynthia Sass, Mph,, 12 Aug. 2020 Watermelon also contains the amino acid citrulline that dilates blood vessels and, according to some, acts as a sort of natural Viagra. Paul Cappiello, The Courier-Journal, 3 July 2020 Still others, like caffeine and citrulline malate, have more equivocal evidence. Sara Chodosh, Popular Science, 3 Jan. 2019 What’s more, watermelon has an amino acid called l-citrulline, which may diminish muscle soreness after intense exercise. NBC News, 11 July 2018 Most notably, citrulline converts to arginine, which is vital to the heart and improves circulation, according to Texas A&M's Fruit and Vegetable Improvement Center. Rebecca Shinners, Country Living, 2 June 2017 Recent research also suggests that inside the rind there are high doses of citrulline, a compound linked to a range of benefits. Rebecca Shinners, Country Living, 2 June 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'citrulline.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of citrulline

1930, in the meaning defined above

History and Etymology for citrulline

International Scientific Vocabulary, from New Latin Citrullus, genus name of the watermelon

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The first known use of citrulline was in 1930

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Dictionary Entries Near citrulline

citrovorum factor



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Cite this Entry

“Citrulline.” Dictionary, Merriam-Webster, Accessed 3 Dec. 2021.

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More Definitions for citrulline


cit·​rul·​line | \ ˈsi-trə-ˌlēn; si-ˈtrəl-ˌēn, -ən How to pronounce citrulline (audio) \

Medical Definition of citrulline

: a crystalline amino acid C6H13N3O3 formed especially as an intermediate in the conversion of ornithine to arginine in the living system

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