theanine

noun

the·​a·​nine ˈthē-ə-ˌnēn 

variants or L-theanine

ˈel-ˈthē-ə-ˌnēn 

: an amino acid C₇H₁₄N₂O₃ found especially in green tea and used as a dietary supplement

Green tea, which is rich in a depression-fighting amino acid called theanine, has previously been lauded for its health benefits.

—Camilla Turner

Examples of theanine in a Sentence

Recent Examples on the Web

This sleep aid by Life Time combines 300 milligrams of magnesium with ashwagandha and L-theanine. —Noor Lobad, Footwear News, 19 Nov. 2025

However, most research on the synergistic effects of L-theanine and magnesium has been done on animals. —Staff Author, Verywell Health, 28 Oct. 2025

In addition to containing much less caffeine than coffee, black tea provides L-theanine, which has a calming effect on the body. —Jillian Kubala, Health, 22 Oct. 2025

This gluten-free, dairy-free, vegan tablet is also supercharged with L-theanine, another stress-balancing adaptogen, for total relaxation amidst the most turbulent of days. —Brianna Peters, Vogue, 10 Oct. 2025

Word History

First Known Use

1950, in the meaning defined above

Rhymes for theanine

• acridine
• alkaline
• andesine
• anodyne
• anticline
• arginine
• asinine
• atropine
• benzidine
• borderline
• byzantine
• calamine