Research

Below is a variety of research studies that have been completed on the effects of l-theanine and the human body.

Effects of L-theanine on attention and reaction time response.

A. Higashiyama
Journal of Functional Foods. 2011 May
www.nutraingredients.com

A combination of green tea extract and l-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo-controlled study.

Park, SK
J Med Food. 2011 Apr
www.ncbi.nlm.nih.gov

Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial.

Matsumoto, K
BMC Complement Altern Med. 2011 Feb 21
www.ncbi.nlm.nih.gov

L-theanine relieves positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective disorder: an 8-week, randomized, double-blind, placebo-controlled, 2-center study.

Ritsner, MS
J Clin Psychiatry. 2011 Jan
www.ncbi.nlm.nih.gov

Standardized capsule of Camellia sinensis lowers cardiovascular risk factors in a randomized, double-blind, placebo-controlled study.

Nantz, M.P..
Nutrition. February 2009
www.ncbi.nlm.nih.gov

L-Theanine, γ-glutamylethylamide, a unique amino acid leaves, modulates neurotransmitter concentrations in striatum interstitium in conscious rats.

Yamada, T.
Amino Acids 2009 36:21-27

Altered levels of oxidation and phospholipase C isozyme expression in the brains of theanine-administered rats.

Nishida, K.
Biol. Pharm. Bull 31 (5) 857-860 (2008)
www.ncbi.nlm.nih.gov

L-theanine and caffeine in combination affect human cognition as evidenced by oscillatory alpha-band activity and attention task performance.

kelley, S.
Journal of Nutrition, Vol 138, No.8, August 2008.
www.ncbi.nlm.nih.gov

L-Theanine elicits an umami taste with inosine 5'-monophosphate

Narukawa, M.
Biosci. biotechnol. Biochem, 72 (11), 3015-3017,2008
www.ncbi.nlm.nih.gov

L-theanine intervention enhances human lymphocyte function

Bukowski, J.
Nutritional Reviews Vol. 66(2); 96-102, 2008
www.ncbi.nlm.nih.gov

Protective effect of the green tea component, L-theanine on environmental toxins-induced neuronal cell death.

Cho, H.S.
NeuroToxicology 656-662 (2008)
www.ncbi.nlm.nih.gov

Standardized capsule of camellia sinensis lowers cardiovascular risk factors in a randomized, double-blind, placebo-controlled study.

Nantz P., Meri.
et al./Nutrition (2008)
www.ncbi.nlm.nih.gov

The combined effects of L-theanine and caffeine on cognitive performance and mood.

Owen, G.
Nutr.Neurosci. Vol. 11, No.4, August 2008.
www.ncbi.nlm.nih.gov

Theanine prevents memory impairment induced by repeated cerebral ischemia in rats.

Egashira, N.
Phytotherapy research, Phytother. Res 22, 65-68 (2008)
www.ncbi.nlm.nih.gov

Theanine, an ingredient of green tea, inhibits Glutamine transport in neurons and astroglia in rat brain.

Kakuda, T.
Journal of Neuroscience Research 86:1846-1856 (2008)
www.ncbi.nlm.nih.gov

Efficacy (against premenstrual syndrome) and short term safety of L-theanine in a randomized, double-blind, parallel-group study in humans.

Timmcke, J.
The FASEB journal. 2008
www.fasebj.org

L-theanine, a natural constituent in tea, and its effect on mental state in humans.

Nobre, A
Asia Pac J Clin Nutr., Vol 17, 2008
www.ncbi.nlm.nih.gov

Effects of L-theanine, a unique amino Acid in tea leaves, on memory.

Yamada, T.
Biosci Biotechnol Biochem, Vol 72, No 5, May 2008
www.ncbi.nlm.nih.gov

Efficacy (against premenstrual syndrome) and short term safety of L-theanine in a randomized, double-blind, parallel-group study in humans.

Timmcke, J.
The FASEB Journal. 2008; 22:lb760
www.fasebj.org

Psychological effects of dietary components of tea: caffeine and L-theanine.

Bryan, J.
Nutr Rev, Vol 66, 2, pp 82-90. Feb 2008
www.ncbi.nlm.nih.gov

L-theanine intervention enhances human gamma delta T lymphocyte function.

Bukowski, J.br /> Nutr Rev, Vol 66, 2, pp 96-102. Feb 2008
www.ncbi.nlm.nih.gov

The effects of L-theanine, caffeine and their combination on cognition and mood.

Haskell, C.F
Biol Psychol, Vol 77, 2, pp 113-22, Feb 2008
www.ncbi.nlm.nih.gov

Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together.

Rogers, P.J.
Psychopharmacology, Vol 195, 4, pp 569-577, Jan 2008
www.ncbi.nlm.nih.gov

L-theanine, r-glutamylethylamide, increases neurotransmission concentrations and neurotrophin mRNA levels in the brain during lactation.

Yamada, T.
Life Sciences. Vol 81, 16, pp 1247-1255. 2007
www.ncbi.nlm.nih.gov

Specific Formulation of Camellia sinensis Prevents Cold and Flu Symptoms and Enhances γδ T Cell Function: A Randomized, Double-Blind, Placebo-Controlled Study

Cheryl A. Rowe, PhD, et. al.
Journal of the American College of Nutrition, Vol. 26 No. 5, 445?452 (2007)
www.ncbi.nlm.nih.gov

Theanine prevents memory impairment induced by repeated cerebral ischemia in rats.

Egashira N, et. al.
Phytother Res. 2007 Aug 17
www.ncbi.nlm.nih.gov

Clinical Efficacy of L-theanine tablets to reduce anxiety-related emotional disorders in cats: A pilot open-label clinical trial.

Dramard, V., Abstract - Journal of Veterinary Behavior, Vol 2, No 3, May/June 2007

Use of L-theanine tablets and behaviour modification for treatment of phobias in dogs: A preliminary study.

Berteselli, G.V., Abstract - Journal of Veterinary Behavior, Vol 2, No 3, May/June 2007

The deployment of intersensory selective attention: a high-density electrical mapping study of the effects of theanine.

Ramirez M, et al., Clin Neuropharmacol, Jan-Feb 2007
www.ncbi.nlm.nih.gov

The neuropharmacology of L-Theanine (N-Ethyl-L-Glutamine): A possible neuroprotective and cognitive enhancing agent.

Nathan, P., Journal of Herbal Pharmacotherapy 2006, Vol 6(2) pp 21-30.

Combined effects of L-theanine and caffeine on cognition and mood.

Parnell, H., Appetite London 2006, Vol 47, No 2, page 273.

Suntheanine reduces psychological and physiological stress responses.

Kimura K, et al., Biol Psychol, Aug 21 2006.
www.ncbi.nlm.nih.gov

Pharmacology and therapeutic uses of L-theanine.

Eschenauer G, et al. American J. Health-Syst Pharm, Vol 63, Jan 1, 2006.
www.ncbi.nlm.nih.gov

Factors that Affect the Body's Nervous System: Relaxation Effects of Suntheanine.

Ozeki M et. al., Nutraceutical Proteins and Peptides in Health and Disease, CRC Press, 2006, pp 377-390.
www.crcpress.com

Effects of Suntheanine on alcohol metabolism and hepatic toxicity.

Sadzuka Y., Biol Phar. Bull., Vol 28, No 9, September 2005.
www.ncbi.nlm.nih.gov

Effects of Suntheanine on neurotransmitter release and its relationship with glutamic acid neurotransmission.

Yamada T., Nutritional Neuroscience, August 2005, 219-226.
www.ncbi.nlm.nih.gov

Effect of Suntheanine on bodyweight and fat accumulation in mice.

Zheng G, et al. Animal Science Journal, Vol76, Issue 2, April 2005
Japanese Society of Animal Science

Pharmacokinetics of Suntheanine shown. Poor absorption, unkown safety and efficacy of racemic mixtures confirmed.

Desai MJ, Gill MS, Hsu WH, Armstrong DW. Chirality 17:154-162, March 2005.
www.ncbi.nlm.nih.gov

Suntheanine shown to reduce adverse reactions of doxorubicin.

Sugiyama T. Cancer Letters, 2004 Aug 30, Vol 212, pp 177-84.
www.ncbi.nlm.nih.gov

Possible neuroprotective effect of Suntheanine.

Nagasawa, K. Biochem. And Biophys. Research Communications 320 (2004) 116-122.
www.ncbi.nlm.nih.gov

Neuroprotective effect of Suntheanine on cerebral infarction.

Egashira, N. Neuroscience Letters, 2004, Vol 363, pp 58-61.
www.ncbi.nlm.nih.gov

Anti-obesity effects of Sunphenon and Suntheanine.

Zheng G, Sayama K, Okubo T, Juneja LR, Oguni I. In Vivo, Vol 18, 2004 Jan. pp 55-62.
www.ncbi.nlm.nih.gov

Analysis of theanine enantiomers by HPLC/atmospheric pressure ionization-mass spectrometry. Suntheanine only true L-theanine.

Desai MJ, Armstrong D.W. Rapid Commun Mass Spectrom, Vol 18, 2004, pp. 251-6.
www.ncbi.nlm.nih.gov

Effects of Suntheanine on brain alpha waves in adult males.

Song, Chan Hee. Dept. of Family Medicine, Obesity Clinic, St. Mary's Hospital, Catholic University of Korea. The Korean Nutrition Society. 2003 36(9): 918-923.

Effect of Suntheanine on doxorubicin-induced adverse reaction.

Sugiyama T. Proceedings of the AACR, Vol 44, 2nd ed., July 2003.

Suntheanine enhances efficacy of chemotherapeutic agents.

Sugiyama T, Sadzuka Y. Biochim Biophys Acta. 2003 Dec 5.
www.ncbi.nlm.nih.gov

Glutamate transporter mediated increase of antitumor activity of Suntheanine

Sadzuka Y, et. al., Yakugaku Zasshi No. 11 2002 Nov pp. 995-9, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan.
www.ncbi.nlm.nih.gov

Suntheanine shown to enhance the therapeutic efficacy of doxorubicin.

Sugiyama T, Sadzuka Y, Tanaka K, Sonobe T. Tox Lett 2001 Apr 30;121(2):89-96.
www.ncbi.nlm.nih.gov

Improving Effect of Suntheanine on Premenstrual Syndrome

Ueda T. et al. Journal of JSPOG Vol. 6, No. 2, pp 234-239, Dec 2001.

Effect of brain alpha wave activity and golf performance by Suntheanine.

Kim K, Yum K, Lee Y. Int'l Symposium on Food, Nutrition and Health, Korean Society of Food Science and Nutr. Dec 7-8, 2001: 50-51.

Correlations between central nervous parameters and hormonal regulations during recovery from physical stress influenced by Suntheanine.

Weiss M, Schnittker R, Barthel T, Falke W, Juneja L.R. Amino Acids (Vienna) 2001 Aug; Vol. 21, No. 1, PP 62.

Effect of Suntheanine on brain monoamines, striatal dopamine release and behavior.

Yokogoshi H, Terashima T. Nutrition 2000, Sep; 16(9):776-777.
www.ncbi.nlm.nih.gov

Efficacies of tea components on doxorubicin induced antitumor activity and reversal of multi-drug resistance.

Sadzuka Y, et al. Toxicol Lett. 2000 Apr 3;114(1-3):155-62.
www.ncbi.nlm.nih.gov

Effect of Suntheanine Intake on Learning Ability.

Terashima T. et al. Fourth Shizuoka Forum on Health and Longevity. Nov 18, 1999 p.82-83.

Suntheanine and its relaxation effect in humans.

Juneja LR, Trends in Food Sci. Tech. June 1999. v10 (6/7) p. 199-204.
www.sciencedirect.com

Suntheanine induced reduction of brain serotonin.

Yokogoshi H, et al. Biosci Biotechnol Biochem. 1998 Apr;62(4):816-7.
www.ncbi.nlm.nih.gov

Effects of Suntheanine on the release of alpha waves in human volunteers.

Kobayashi A, et al. Nippon Nogeikagaku Kaishi. 1998 v72, 153-157.

Effect of Suntheanine on brain monoamines and dopamine.

Yokogoshi H, et al. Neurochem Res. 1998 May;23(5):667-73.
www.ncbi.nlm.nih.gov

Hypotensive effect of Suntheanine

Yokogoshi H, et al. Life Sci. 1998;62(12):1065-8.
www.ncbi.nlm.nih.gov

Effect of Suntheanine on norepinephrine and serotonin levels.

Kimura R, et al. Chem Pharm Bull (Tokyo). 1986 Jul;34(7):3053-7.
www.ncbi.nlm.nih.gov