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

However, matcha’s high levels of L-theanine, a calming amino acid, help balance caffeine’s stimulating effects. —Jillian Kubala, Health, 19 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

Some experts believe that L-theanine helps minimize blood sugar spikes associated with caffeine intake. —Team Verywell Health, Verywell Health, 6 Oct. 2025

The new formula also includes L-theanine, a non-protein amino acid primarily found in green and black tea and some mushrooms, Healthline states. —Greta Cross, USA Today, 5 Sep. 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