Theanine

Not to be confused with threonine, a distinct amino acid, or theine, an archaic synonym of caffeine.

Theanine
skeletal formula of L-theanine
L-Theanine
Clinical data
Other namesγ-L-Glutamylethylamide
Dependence
liability		None
Routes of
administration		Oral
Drug classdietary supplement
ATC code
  • none
Legal status
Legal status
  • US: OTC
  • UN: Unscheduled
Pharmacokinetic data
Onset of actionabout 1 hour[1]
Elimination half-lifeCapsule ~1.2 hours
Green Tea ~0.8 hours[1]
Identifiers
  • (2S)-2-Ammonio-5-(ethylamino)-5-oxopentanoate[2] or N-Ethyl-L-glutamine
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.019.436 Edit this at Wikidata
Chemical and physical data
FormulaC7H14N2O3
Molar mass174.200 g·mol−1
3D model (JSmol)
Melting point174.20 °C (345.56 °F) [3]
Boiling point215 °C (419 °F) [3]
  • CCNC(=O)CC[C@H](N)C(=O)O

  • CCNC(=O)CCC(N)C(O)=O
  • InChI=1S/C7H14N2O3/c1-2-9-6(10)4-3-5(8)7(11)12/h5H,2-4,8H2,1H3,(H,9,10)(H,11,12) checkY
  • Key:DATAGRPVKZEWHA-UHFFFAOYSA-N checkY

Theanine /ˈθiːəniːn/, commonly known as L-theanine and sometimes L-gamma-glutamylethylamide or N5-ethyl-L-glutamine, is an amino acid analogue of the proteinogenic amino acids L-glutamate and L-glutamine and is found primarily in particular plant and fungal species.[3][4] It was discovered as a constituent of green tea in 1949 and isolated from gyokuro leaves in 1950, thus rendering it a natural product.[5] It constitutes about 1–2% of the dry weight of green tea leaves.[4]

The name theanine without a prefix generally implies the enantiomer L-theanine, which is the form found in tea leaves from which it is extracted as a powder.[4][6] The right-handed enantiomer, D-theanine, has been comparatively studied less.

Theanine is sold as a dietary supplement and is considered to be safe at doses up to 250 milligrams (mg) by the US Food and Drug Administration.[4][7] It is packaged in gelatin capsules, tablets, and as a powder, and may be an ingredient in branded supplements with caffeine.

The European Food Safety Authority found there was insufficient evidence for a causal relationship between theanine consumption and improved cognitive function, alleviation of psychological stress, maintenance of normal sleep, or reduction of menstrual discomfort.[8]

  1. ^ a b Scheid L, Ellinger S, Alteheld B, Herholz H, Ellinger J, Henn T, et al. (December 2012). "Kinetics of L-theanine uptake and metabolism in healthy participants are comparable after ingestion of L-theanine via capsules and green tea". The Journal of Nutrition. 142 (12): 2091–2096. doi:10.3945/jn.112.166371. PMID 23096008.
  2. ^ Cite error: The named reference RSC_Chemspider was invoked but never defined (see the help page).
  3. ^ a b c "L-Theanine". PubChem, US National Library of Medicine. 13 May 2023. Retrieved 16 May 2023.
  4. ^ a b c d "L-Theanine". Drugs.com. 20 February 2023. Retrieved 16 May 2023.
  5. ^ "Components of Gyokuro｜ IPPODO". Ippodo-tea.co.jp. Archived from the original on 2015-12-23. Retrieved 2015-05-07.
  6. ^ Schuster J, Mitchell ES (March 2019). "More than just caffeine: psychopharmacology of methylxanthine interactions with plant-derived phytochemicals". Progress in Neuro-Psychopharmacology & Biological Psychiatry. 89: 263–274. doi:10.1016/j.pnpbp.2018.09.005. PMID 30213684. S2CID 52274913.
  7. ^ "GRAS notice for L-theanine". US Food and Drug Administration. 5 February 2007. Retrieved 1 May 2023.
  8. ^ EFSA Panel on Dietetic Products, Nutrition and Allergies, European Food Safety Authority (2011). "Scientific Opinion on the substantiation of health claims related to L-theanine from Camellia sinensis (L.) Kuntze (Tea) and improvement of cognitive function (ID 1104, 1222, 1600, 1601, 1707, 1935, 2004, 2005), alleviation of psychological stress (ID 1598, 1601), maintenance of normal sleep (ID 1222, 1737, 2004) and reduction of menstrual discomfort (ID 1599) pursuant to Article 13(1) of Regulation (EC) No 1924/2006". EFSA Journal. 9 (6): 2238. doi:10.2903/j.efsa.2011.2238.