Other Names: gamma-glutamylethylamide, 5-N-ethyl-glutamine

Suntheanine® is a patented name of a pure form of L-theanine. This pure L-isomer-theanine is produced through a proprietary fermentation process in order to guarantee that it is highly potent and provides maximum health benefits.

L-theanine has been shown through various studies to help support optimal energy levels, concentration and mental clarity as well as thought processes that play a role in learning and memory; all of which can help the body cope with stress. It also supports better alertness, a pleasant mood and relaxation.

Furthermore, L-theanine has been shown to help:

  • Support immune system function
  • Aid the body’s absorption of antioxidants
  • Enhance circulatory functions that are essential for optimal blood flow
  • Support the body’s natural defenses that protect healthy cells and DNA from toxins and oxidative stress

L-theanine is a natural and useful amino acid found in green tea that has been shown through substantial research to promote mental calmness and relaxation without disrupting concentration or causing fatigue. L-theanine supports healthy levels of proteins that protect cells in the brain. It also promotes alpha frequency band and brain wave activity, which is associated with relaxation. This means that adequate levels of L-theanine have the ability to aid biological processes that play a role in mental arousal, alertness, and general mental health. Overall, L-theanine aids numerous processes in the body and is essential for optimal physical and mental health.

Studies on L-Theanine:

  1. Tsutomu Okubo, Tomoko Ueda, Makoto Ozeki, Lekh R. Juneja, Hidehiko Yokogoshi, and Seiichi Matsumoto. L-Theanine – A unique amino acid of green tea and its phsiological effects in humans. Taiyo Kagaku Co., Ltd., 1-3 Takaramachi Yokkaichi-shi, Mie, 510-0844.
  2. Yoto A, Motoki M, Murao S, Yokogoshi H. Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses. J Physiol Anthropol. 2012 Oct 29;31:28. doi: 10.1186/1880-6805-31-28.
  3. Kimura K, Ozeki M, Juneja LR, Ohira H. L-Theanine reduces psychological and physiological stress responses. Biol Psychol. 2007 Jan;74(1):39-45. Epub 2006 Aug 22.
  4. Kurihara S, Hiraoka T, Akutsu M, Sukegawa E, Bannai M, Shibahara S. Effects of (L)-cystine and (L)-theanine supplementation on the common cold: a randomized, double-blind, and placebo-controlled trial. J Amino Acids. 2010;2010:307475. doi: 10.4061/2010/307475. Epub 2010 May 12.
  5. Kimura K, Ozeki M, Juneja LR, Ohira H. L-Theanine reduces psychological and physiological stress responses. Biol Psychol. 2007 Jan;74(1):39-45. Epub 2006 Aug 22.
  6. Jack F Bukowski and Susan S Percival. L-theanine intervention enhances human T lymphocyte function. Nutrition Reviews (Impact Factor: 5.54). 03/2008; 66(2):96-102.
  7. Kim NH, Jeong HJ, Kim HM. Theanine is a candidate amino acid for pharmacological stabilization of mast cells. Amino Acids. 2012 May;42(5):1609-18. doi: 10.1007/s00726-011-0847-9. Epub 2011 Feb 23.
  8. Tsutomu Okubo, Tomoko Ueda, Makoto Ozeki, Lekh R. Juneja, Hidehiko Yokogoshi, and Seiichi Matsumoto. L-Theanine – A unique amino acid of green tea and its physiological effects in humans.

Other research:

  1. Jiang W, Gao M, Sun S, Bi A, Xin Y, Han X, Wang L, Yin Z, Luo L. Protective effect of L-theanine on carbon tetrachloride-induced acute liver injury in mice. Biochem Biophys Res Commun. 2012 Jun 1;422(2):344-50. doi: 10.1016/j.bbrc.2012.05.022. Epub 2012 May 11.
  2. Pérez-Vargas JE, Zarco N, Vergara P, Shibayama M, Segovia J, Tsutsumi V, Muriel P. l-Theanine prevents carbon tetrachloride-induced liver fibrosis via inhibition of nuclear factor κB and down-regulation of transforming growth factor β and connective tissue growth factor. Hum Exp Toxicol. 2015 Apr 7. pii: 0960327115578864. [Epub ahead of print]
  3. Sumathi T, Shobana C, Thangarajeswari M, Usha R. Protective effect of L-Theanine against aluminium induced neurotoxicity in cerebral cortex, hippocampus and cerebellum of rat brain – histopathological, and biochemical approach. Drug Chem Toxicol. 2015 Jan;38(1):22-31. doi: 10.3109/01480545.2014.900068. Epub 2014 Mar 24.
  4. Thangarajan S, Deivasigamani A, Natarajan SS, Krishnan P, Mohanan SK. Neuroprotective activity of L-theanine on 3-nitropropionic acid-induced neurotoxicity in rat striatum. Int J Neurosci. 2014 Sep;124(9):673-84. doi: 10.3109/00207454.2013.872642. Epub 2014 Jan 23.
  5. Tian X, Sun L, Gou L, Ling X, Feng Y, Wang L, Yin X, Liu Y. Protective effect of l-theanine on chronic restraint stress-induced cognitive impairments in mice. Brain Res. 2013 Mar 29;1503:24-32. doi: 10.1016/j.brainres.2013.01.048. Epub 2013 Feb 5.
  6. Kim TI, Lee YK, Park SG, Choi IS, Ban JO, Park HK, Nam SY, Yun YW, Han SB, Oh KW, Hong JT. l-Theanine, an amino acid in green tea, attenuates beta-amyloid-induced cognitive dysfunction and neurotoxicity: reduction in oxidative damage and inactivation of ERK/p38 kinase and NF-kappaB pathways. Free Radic Biol Med. 2009 Dec 1;47(11):1601-10. doi: 10.1016/j.freeradbiomed.2009.09.008. Epub 2009 Sep 16.
  7. Cho HS, Kim S, Lee SY, Park JA, Kim SJ, Chun HS. Protective effect of the green tea component, L-theanine on environmental toxins-induced neuronal cell death. Neurotoxicology. 2008 Jul;29(4):656-62. doi: 10.1016/j.neuro.2008.03.004. Epub 2008 Mar 20.
  8. Lee SI, Kim HJ, Boo YC. Effect of green tea and (-)-epigallocatechin gallate on ethanol-induced toxicity in HepG2 cells. Phytother Res. 2008 May;22(5):669-74. doi: 10.1002/ptr.2390.
  9. Ross SM. L-theanine (suntheanin): effects of L-theanine, an amino acid derived from Camellia sinensis (green tea), on stress response parameters. Holist Nurs Pract. 2014 Jan-Feb;28(1):65-8. doi: 10.1097/HNP.0000000000000009.
  10. Yoto A, Motoki M, Murao S, Yokogoshi H. Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses. J Physiol Anthropol. 2012 Oct 29;31:28. doi: 10.1186/1880-6805-31-28.
  11. Yin C, Gou L, Liu Y, Yin X, Zhang L, Jia G, Zhuang X. Antidepressant-like effects of L-theanine in the forced swim and tail suspension tests in mice. Phytother Res. 2011 Nov;25(11):1636-9. doi: 10.1002/ptr.3456. Epub 2011 Mar 21.
  12. Kimura K, Ozeki M, Juneja LR, Ohira H. L-Theanine reduces psychological and physiological stress responses. Biol Psychol. 2007 Jan;74(1):39-45. Epub 2006 Aug 22.
  13. Dimpfel W, Pischel I, Lehnfeld R. Effects of lozenge containing lavender oil, extracts from hops, lemon balm and oat on electrical brain activity of volunteers. Eur J Med Res. 2004 Sep 29;9(9):423-31.
  14. Kurihara S, Shibahara S, Arisaka H, Akiyama Y. Enhancement of antigen-specific immunoglobulin G production in mice by co-administration of L-cystine and L-theanine. J Vet Med Sci. 2007 Dec;69(12):1263-70.
  15. Takagi Y, Kurihara S, Higashi N, Morikawa S, Kase T, Maeda A, Arisaka H, Shibahara S, Akiyama Y. Combined administration of (L)-cystine and (L)-theanine enhances immune functions and protects against influenza virus infection in aged mice. J Vet Med Sci. 2010 Feb;72(2):157-65. Epub 2009 Nov 25.
  16. Vuong QV, Bowyer MC, Roach PD. L-Theanine: properties, synthesis and isolation from tea. J Sci Food Agric. 2011 Aug 30;91(11):1931-9. doi: 10.1002/jsfa.4373. Epub 2011 Mar 29.
  17. Kurihara S, Hiraoka T, Akutsu M, Sukegawa E, Bannai M, Shibahara S. Effects of (L)-cystine and (L)-theanine supplementation on the common cold: a randomized, double-blind, and placebo-controlled trial. J Amino Acids. 2010;2010:307475. doi: 10.4061/2010/307475. Epub 2010 May 12.

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These statements have not been evaluated by the FDA. This product is not intended to prevent, treat, cure, or diagnose any disease. Information on this site is for educational purposes only. It is not medical advice. Consult a physician if you are seeking medical advice or have a medical problem.

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