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

Deepkold offers Focus and Energy pouches with 50 mg caffeine and 50 mg L-theanine, a caffeine-free Shroom Frost built around lion’s mane, cordyceps, reishi and B12, and Deep Calm for sleep with melatonin, L-theanine and magnesium glycinate. — Hanna Wickes, Kansas City Star, 20 Oct. 2026

Most pair stimulants like caffeine or paraxanthine with focus-support compounds like L-theanine, citicoline and rhodiola, plus adaptogens like lion’s mane and ashwagandha. — Hanna Wickes, Charlotte Observer, 20 Oct. 2026

Some studies suggest that L-theanine may increase alpha waves in the brain, which have a calming, relaxing effect and can improve sleep quality. — Emmanuella Ogbonna, HEALTH, 2 Oct. 2026

Melatonin has more evidence for sleep timing, while L-theanine supports relaxation without causing sedation. — T'keyah Bazin, Verywell Health, 25 Sep. 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
• brucine
• byline