Theanine

Theanine
	L-Theanine
Clinical data
Other names	γ-L-Glutamylethylamide
Dependence; liability	None
Routes of; administration	Oral
Drug class	dietary supplement
ATC code	none;
Legal status
Legal status	US: OTC; UN: Unscheduled;
Pharmacokinetic data
Onset of action	about 1 hour
Elimination half-life	Capsule ~1.2 hours ; Green Tea ~0.8 hours
Identifiers
	IUPAC name (2S)-2-Ammonio-5-(ethylamino)-5-oxopentanoate or N-Ethyl-L-glutamine;
CAS Number	3081-61-6 ;
PubChem CID	439378;
DrugBank	DB12444;
ChemSpider	388498 ;
UNII	8021PR16QO;
KEGG	C01047;
ChEBI	CHEBI:17394 ;
ChEMBL	ChEMBL3039113;
CompTox Dashboard (EPA)	DTXSID80184817 ;
ECHA InfoCard	100.019.436
Chemical and physical data
Formula	C7H14N2O3
Molar mass	174.200 g·mol−1
3D model (JSmol)	Interactive image; Interactive image;
Melting point	174.20 °C (345.56 °F)
Boiling point	215 °C (419 °F)
	SMILES CCNC(=O)CC[C@H](N)C(=O)O; ; CCNC(=O)CCC(N)C(O)=O;
	InChI 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) ; Key:DATAGRPVKZEWHA-UHFFFAOYSA-N ;

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]

^ ^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.
^ Cite error: The named reference RSC_Chemspider was invoked but never defined (see the help page).
^ ^a ^b ^c "L-Theanine". PubChem, US National Library of Medicine. 13 May 2023. Retrieved 16 May 2023.
^ ^a ^b ^c ^d "L-Theanine". Drugs.com. 20 February 2023. Retrieved 16 May 2023.
^ "Components of Gyokuro｜ IPPODO". Ippodo-tea.co.jp. Archived from the original on 2015-12-23. Retrieved 2015-05-07.
^ 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.
^ "GRAS notice for L-theanine". US Food and Drug Administration. 5 February 2007. Retrieved 1 May 2023.
^ 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.

[PK-1] 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.

[RSC_Chemspider-2] Cite error: The named reference RSC_Chemspider was invoked but never defined (see the help page).

[pubchem-3] "L-Theanine". PubChem, US National Library of Medicine. 13 May 2023. Retrieved 16 May 2023.

[drugs-4] "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.

[gras-7] "GRAS notice for L-theanine". US Food and Drug Administration. 5 February 2007. Retrieved 1 May 2023.

[efsa-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.

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