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

Each can contains a lovely 60 mg of caffeine and 30 mg of L-theanine—just enough to add a brighter sheen in the afternoon. —Alaina Chou, Bon Appetit Magazine, 30 Apr. 2026

Many menopause supplements contain black cohosh, maca root powder, and L-theanine. —Stephanie Brown, Verywell Health, 29 Apr. 2026

The gymnast also finds balance with Pure Leaf Mental Focus, a line of sparkling iced teas with naturally occurring caffeine and L-theanine, per a press release shared with PEOPLE. —Chiara Kim, PEOPLE, 28 Apr. 2026

One cup of green or black tea contains roughly 25 to 60mg of L-theanine, so your nightly tea habit is a small but real contribution. —Allison Palmer, Fort Worth Star-Telegram, 23 Apr. 2026

Word History

First Known Use

1950, in the meaning defined above

Rhymes for theanine

• affine
• airline
• align
• aline
• assign
• baseline
• beamline
• benign
• bloodline
• bovine
• byline
• canine