THEANINE could be a highly useful ANXIOLYTIC, since it DOES NOT function as a GABA RECEPTOR AGONIST but UPREGULATES THE PRODUCTION OF GABA within the brain, functions as a GLUTAMATE RECEPTOR ANTAGONIST, and enhances ALPHA-WAVE production within the brain.

See the following studies:

J Clin Psychiatry. 2011 Jan;72(1):34-42. Epub 2010 Nov 30.

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, Miodownik C, Ratner Y, Shleifer T, Mar M, Pintov L, Lerner V.

Department of Psychiatry, The Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.


L-theanine is a unique amino acid present almost exclusively in the tea plant. It possesses neuroprotective, mood-enhancing, and relaxation properties. This is a first study designed to evaluate the efficacy and tolerability of L-theanine augmentation of antipsychotic treatment of patients with chronic schizophrenia and schizoaffective disorder.

60 patients with DSM-IV schizophrenia or schizoaffective disorder participated in an 8-week, double-blind, randomized, placebo-controlled study. 400 mg/d of L-theanine was added to ongoing antipsychotic treatment from February 2006 until October 2008. The outcome measures were the Positive and Negative Syndrome Scale (PANSS), the Hamilton Anxiety Rating Scale (HARS), the Cambridge Neuropsychological Test Automated Battery (CANTAB) for neurocognitive functioning, and additional measures of general functioning, side effects, and quality of life.

40 patients completed the study protocol. Compared with placebo, L-theanine augmentation was associated with reduction of anxiety (P = .015; measured by the HARS scale) and positive (P = .009) and general psychopathology (P < .001) scores (measured by the PANSS 3-dimensional model). According to the 5-dimension model of psychopathology, L-theanine produced significant reductions on PANSS positive (P = .004) and activation factor (P = .006) scores compared to placebo. The effect sizes (Cohen d) for these differences ranged from modest to moderate (0.09-0.39). PANSS negative and CANTAB task scores, general functioning, side effect, and quality of life measures were not affected by L-theanine augmentation. L-theanine was found to be a safe and well-tolerated medication.

L-theanine augmentation of antipsychotic therapy can ameliorate positive, activation, and anxiety symptoms in schizophrenia and schizoaffective disorder patients. Further long-term studies of L-theanine are needed to substantiate the clinically significant benefits of L-theanine augmentation.

PMID: 21208586

J Herb Pharmacother 2006;6(2):21-30.

The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent.

Nathan PJ, Lu K, Gray M, Oliver C.

Behavioural Neuroscience Laboratory, Department of Physiology, Monash Center for Brain and Behaviour, Monash University, Australia. [email protected]

L-theanine (N-ethyl-L-glutamine) or theanine is a major amino acid uniquely found in green tea. L-theanine has been historically reported as a relaxing agent, prompting scientific research on its pharmacology. Animal neurochemistry studies suggest that L-theanine increases brain serotonin, dopamine, GABA levels and has micromolar affinities for AMPA, Kainate and NMDA receptors. In addition has been shown to exert neuroprotective effects in animal models possibly through its antagonistic effects on group 1 metabotrophic glutamate receptors. Behavioural studies in animals suggest improvement in learning and memory. Overall, L-theanine displays a neuropharmacology suggestive of a possible neuroprotective and cognitive enhancing agent and warrants further investigation in animals and humans.

PMID: 17182482

AANA J. 2009 Dec;77(6):445-9.

Anxiolytic effects of L-theanine–a component of green tea–when combined with midazolam, in the male Sprague-Dawley rat.

Heese T, Jenkinson J, Love C, Milam R, Perkins L, Adams C, McCall S, Ceremuga TE.

US Army Graduate Program in Anesthesia Nursing, Carl R. Darnell Army Medical Center, Fort Hood, Texas, USA.

The purpose of the study was to investigate the anxiolytic effects of L-theanine and its potential interaction with the GABAA receptor in Sprague-Dawley rats. L-theanine is a major component of green tea, which has traditionally been used as an herbal remedy in the treatment of many medical conditions, including anxiety. Herbals and supplements and their potential interactions perioperatively are a concern to anesthetists. Fifty-five rats were divided into 5 groups: control (saline); L-theanine (positive control); flumazenil (a known benzodiazepine receptor antagonist) and L-theanine; and midazolam and L-theanine. The behavioral component of anxiety was evaluated using the elevated plus-maze and calculated by the time spent in the open arm of the maze divided by total time in the maze. Data were analyzed using a 2-tailed multivariate analysis of variance and Sheffé posthoc testThe data suggest that L-theanine does not produce anxiolysis by modulation of the GABAA receptor; however, in combination with midazolam, a synergistic or additive effect was demonstrated by decreased anxiety and both fine and basic motor movements. These data may provide direction for further studies examining L-theanine and its effects on anxiety and motor activity.

PMID: 20108732

Clin Neuropharmacol. 2007 Jan-Feb;30(1):25-38.

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

Gomez-Ramirez M, Higgins BA, Rycroft JA, Owen GN, Mahoney J, Shpaner M, Foxe JJ.

Program in Cognitive Neuroscience, Department of Psychology, The City College of the City University of New York, New York, NY, USA.



Ingestion of the nonproteinic amino acid theanine (5-N-ethylglutamine) has been shown to increase oscillatory brain activity in the so-called alpha band (8-14 Hz) during resting electroencephalographic recordings in humans. Independently, alpha band activity has been shown to be a key component in selective attentional processes. Here, we set out to assess whether theanine would cause modulation of anticipatory alpha activity during selective attentional deployments to stimuli in different sensory modalities, a paradigm in which robust alpha attention effects have previously been established.


Electrophysiological data from 168 scalp electrode channels were recorded while participants performed a standard intersensory attentional cuing task.


As in previous studies, significantly greater alpha band activity was measured over parieto-occipital scalp for attentional deployments to the auditory modality than to the visual modality. Theanine ingestion resulted in a substantial overall decrease in background alpha levels relative to placebo while subjects were actively performing this demanding attention task. Despite this decrease in background alpha activity, attention-related alpha effects were significantly greater for the theanine condition.


This increase of attention-related anticipatory alpha over the right parieto-occipital scalp suggests that theanine may have a specific effect on the brain’s attention circuitry. We conclude that theanine has clear psychoactive properties, and that it represents a potentially interesting, naturally occurring compound for further study, as it relates to the brain’s attentional system.
PMID: 17272967