Overview

Theanine is an amino acid found in tea. It is also found in some mushrooms. It is similar in structure to glutamic acid, another amino acid.

Some people take theanine by mouth for anxiety and stress, depression, schizophrenia, for preventing Alzheimer's disease, for treating attention deficit-hyperactivity disorder (ADHD), and improving mental performance and attention. Theanine is also taken by mouth for reducing blood pressure, preventing the flu, and improving how well cancer drugs work as well as decreasing the side effects of cancer drugs.

Classification

Is a Form of:

Amino Acid found in tea

Primary Functions:

Anxiety, stress, depression, schizophrenia

Also Known As:

Gamma-ethylamino-L-glutamic acid, Gamma-glutamylethylamide, Gamma-N-ethylglutamine

How Does It Work?

Theanine has a chemical structure very similar to glutamate, a naturally occurring amino acid in the body that helps transmit nerve impulses in the brain. Some of the effects of theanine appear to be similar to glutamate, and some effects seem to block glutamate.

Uses

Mental performance. Taking theanine before a test seems to help reduce errors. Taking theanine with caffeine seems to improve a person's ability to switch attention between different tasks.

Recommended Dosing

The following doses have been studied in scientific research:

ADULTS

BY MOUTH:

• For mental performance: A single dose of 100 mg of theanine before a test has been used. Theanine has also been used in combination with caffeine. Combination doses have ranged from 30-100 mg of caffeine and 12-100 mg of theanine.

Theanine Supplements Frequently Asked Questions

What is the difference between L Theanine and theanine?

Theanine. Theanine, also known as L-theanine, is a non-protein amino acid mainly found naturally in green tea (Camellia sinensis) and some mushrooms (Boletus badius). Theanine is related to glutamine, is speculated to increase levels of GABA, serotonin, and dopamine. Recently, theanine has also been marketed in the US.

Are there any side effects to L Theanine?

Studies have not found side effects from using theanine supplements. Drinking lots of green tea can cause upset stomach and irritability from the caffeine.

Does L theanine help with anxiety?

An amino acid in green tea helps reduce generalized anxiety.

The amino acid L-theanine is an effective treatment of moderate and severe anxiety and does not cause drowsiness.  A calming effect is usually noted within 30 to 40 minutes after L-theanine is taken at a dose of 50 to 200mg, and typically lasts 8 to 10

How long does L Theanine take to kick in?

Calming effects may last 8 to 10 hours and are usually experienced within 30 minutes following ingestion of l-theanine at doses between 50 and 200 mg.

Does L Theanine cause liver damage?

According to a paper from Anhui Agricultural University in China, theanine can protect liver tissue, minimising damage to the liver from chronic inflammation and its resultant diseases. The amino acid was found to increase antioxidant enzyme activity in mice, and to improve the human immune system.

Is L Theanine a muscle relaxer?

BETTER SLEEP - L-Theanine enables the body to produce other calming amino acids, such as dopamine, GABA and Tryptophan and helps with concentration, focus, deep muscle relaxation and improved quality sleep so you feel bullet proof.

Does L Theanine make you sleep?

L-theanine may help people fall asleep more quickly and easily at bedtime, thanks to the relaxation boost it delivers. Research also shows L-theanine can improve the quality of sleep—not by acting as a sedative, but by lowering anxiety and promoting relaxation.

Who should not take L Theanine?

Stay on the safe side and avoid use. Children: Theanine is POSSIBLY SAFE for children when taken by mouth, short-term. Doses of 200 mg of theanine have been safely used twice daily for up to 6 weeks in boys aged 8-12 years. Low blood pressure: Theanine might lower blood pressure.

Does L Theanine make you gain weight?

The anti-anxiety and sleep-promoting abilities of L-theanine may help people to maintain a healthy weight. After all, getting enough sleep and limiting stress are both key to sticking with a healthy diet and avoiding weight gain. L-theanine may also play a more direct role in weight maintenance.

How often should you take L Theanine?

Moderately severe anxiety symptoms may respond to l-theanine taken at a dose of 200 mg twice daily; however, more severe anxiety may require doses up to 600 to 800 mg per day divided into 200-mg increments every 3 to 4 hours.

Can you take L Theanine with Xanax?

No interactions were found between l-theanine and Xanax. This does not necessarily mean no interactions exist. Always consult your healthcare provider.

Can you build tolerance to L Theanine?

Unlike prescription benzodiazepine medications, l-theanine is not habit-forming as it does not lead to tolerance and dependence when used over long periods of time.

Does L Theanine increase serotonin?

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.

Can theanine cause diarrhea?

Possible Side Effects

To date, little is known about the safety of using L-theanine supplements in the long term. Due to the caffeine content, excessive consumption of green tea may also trigger certain side effects. These may include a headache, insomnia, irritability, diarrhea, and heartburn.

Is L Theanine anti inflammatory?

L-theanine, a water-soluble amino acid isolated from green tea (Camellia sinensis), has anti-inflammatory activity, antioxidative properties, and hepatoprotective effects. However, the anti-allergic effect of L-theanine and its underlying molecular mechanisms have not been elucidated.

Does L Theanine interact with any medications?

Theanine might decrease blood pressure. Taking theanine along with medications for high blood pressure might cause your blood pressure to go too low. Theanine might work to slow down the nervous system. Taking theanine along with stimulant medications might decrease the effectiveness of stimulant medications.

Can you take L Theanine and 5 HTP together?

No interactions were found between 5-HTP and l-theanine. This does not necessarily mean no interactions exist. Always consult your healthcare provider.

Should I take theanine before bed?

L Theanine has been shown to improve sleep quality. It is not a sedative. But it can improve the quality of sleep by reducing anxiety and promoting relaxation as needed to initiate high quality sleep. One study found that 200 mg before bed improved sleep quality and daytime use did not cause drowsiness.

How long does it take for L Theanine and lemon balm to work?

Calming effects may last 8 to 10 hours and are usually experienced within 30 minutes following ingestion of l-theanine at doses between 50 and 200 mg. However, findings of clinical research studies on l-theanine in anxiety are inconsistent.

Does L Theanine make you happy?

L-Theanine Benefits. ... That high L-Theanine makes us feel mentally and emotionally calmer, it helps us focus and improves retention and recall, it also increases dopamine levels so we feel happier!

Clinical Studies

• ^ a b c d Yamada T, et al. Theanine, r-glutamylethylamide, increases neurotransmission concentrations and neurotrophin mRNA levels in the brain during lactation. Life Sci. (2007)
• ^ a b Differences in free amino acids and total nitrogen contents among various prices of green tea.
• ^ a b Comparison of Azorean tea theanine to teas from other origins by HPLC/DAD/FD. Effects of fermentation, drying temperature, drying time, and shoot maturity.
• ^ a b c d Nobre AC, Rao A, Owen GN. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr. (2008)
• ^ a b c d e f L-theanine—a unique amino acid of green tea and its relaxation effect in humans.
• ^ CASIMIR J, JADOT J, RENARD M. Separation and characterization of N-ethyl-gamma-glutamine from Xerocomus badius. Biochim Biophys Acta. (1960)
• ^ Başkan MH, Aydın M. Electron paramagnetic resonance studies of gamma-irradiated dl-alanine ethyl ester hydrochloride, l-theanine and l-glutamic acid dimethyl ester hydrochloride. Spectrochim Acta A Mol Biomol Spectrosc. (2013)
• ^ 200 mg of Zen: L-Theanine Boosts Alpha Waves, Promotes Alert Relaxation.
• ^ Narukawa M, et al. Nerve and behavioral responses of mice to various umami substances. Biosci Biotechnol Biochem. (2011)
• ^ Narukawa M, Morita K, Hayashi Y. L-theanine elicits an umami taste with inosine 5'-monophosphate. Biosci Biotechnol Biochem. (2008)
• ^ a b c d Lyon MR, Kapoor MP, Juneja LR. The effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial. Altern Med Rev. (2011)
• ^ a b Suntheanine: A pure and safe L-theanine dietary supplement for relaxation and stress relief.
• ^ Process for producing theanine WO 2004016798 A1.
• ^ a b c Kimura K, et al. L-Theanine reduces psychological and physiological stress responses. Biol Psychol. (2007)
• ^ Lu K, et al. The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans. Hum Psychopharmacol. (2004)
• ^ a b Gomez-Ramirez M, et al. The effects of L-theanine on alpha-band oscillatory brain activity during a visuo-spatial attention task. Brain Topogr. (2009)
• ^ a b c d Park SK, et al. 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. J Med Food. (2011)
• ^ Tsuge H, et al. Theanine, gamma-glutamylethylamide, is metabolized by renal phosphate-independent glutaminase. Biochim Biophys Acta. (2003)
• ^ a b Zarse K, Jabin S, Ristow M. L-Theanine extends lifespan of adult Caenorhabditis elegans. Eur J Nutr. (2012)
• ^ a b c d Kimura R, Murata T. Influence of alkylamides of glutamic acid and related compounds on the central nervous system. I. Central depressant effect of theanine. Chem Pharm Bull (Tokyo). (1971)
• ^ a b c d Terashima T, Takido J, Yokogoshi H. Time-dependent changes of amino acids in the serum, liver, brain and urine of rats administered with theanine. Biosci Biotechnol Biochem. (1999)
• ^ a b c Yokogoshi H, et al. Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats. Neurochem Res. (1998)
• ^ Christensen HN. Developments in amino acid transport, illustrated for the blood-brain barrier. Biochem Pharmacol. (1979)
• ^ a b c d e Tamano H, et al. Preventive effect of theanine intake on stress-induced impairments of hippocamapal long-term potentiation and recognition memory. Brain Res Bull. (2013)
• ^ a b Effects of Theanine on the Release of Brain Alpha Wave in Adult Males.
• ^ a b c d e Effects of l-theanine on attention and reaction time response.
• ^ a b The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans.
• ^ Pfurtscheller G. Event-related synchronization (ERS): an electrophysiological correlate of cortical areas at rest. Electroencephalogr Clin Neurophysiol. (1992)
• ^ Gomez-Ramirez M, et al. The deployment of intersensory selective attention: a high-density electrical mapping study of the effects of theanine. Clin Neuropharmacol. (2007)
• ^ Visual spatial attention tracking using high-density SSVEP data for independent brain-computer communication.
• ^ Kelly SP, et al. Increases in alpha oscillatory power reflect an active retinotopic mechanism for distracter suppression during sustained visuospatial attention. J Neurophysiol. (2006)
• ^ Klimesch W, et al. Induced alpha band power changes in the human EEG and attention. Neurosci Lett. (1998)
• ^ a b Kimura R, Murata T. Effect of theanine on norepinephrine and serotonin levels in rat brain. Chem Pharm Bull (Tokyo). (1986)
• ^ Yokogoshi H, Mochizuki M, Saitoh K. Theanine-induced reduction of brain serotonin concentration in rats. Biosci Biotechnol Biochem. (1998)
• ^ a b Kakuda T, et al. Inhibition by theanine of binding of {3H}AMPA, {3H}kainate, and {3H}MDL 105,519 to glutamate receptors. Biosci Biotechnol Biochem. (2002)
• ^ a b Kakuda T, et al. Theanine, an ingredient of green tea, inhibits {3H}glutamine transport in neurons and astroglia in rat brain. J Neurosci Res. (2008)
• ^ Cortese S, et al. Sleep in children with attention-deficit/hyperactivity disorder: meta-analysis of subjective and objective studies. J Am Acad Child Adolesc Psychiatry. (2009)
• ^ Cohen-Zion M, Ancoli-Israel S. Sleep in children with attention-deficit hyperactivity disorder (ADHD): a review of naturalistic and stimulant intervention studies. Sleep Med Rev. (2004)
• ^ Ritsner MS, et al. 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. J Clin Psychiatry. (2011)
• ^ Kim TI, et al. 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)
• ^ a b Schallier A, et al. L-Theanine intake increases threshold for limbic seizures but decreases threshold for generalized seizures. Nutr Neurosci. (2013)
• ^ Dhir A. Pentylenetetrazol (PTZ) kindling model of epilepsy. Curr Protoc Neurosci. (2012)
• ^ Gomes A, et al. Proconvulsive effect of tea (Camellia sinensis) in mice. Phytother Res. (1999)
• ^ a b Takeda A, et al. Unique induction of CA1 LTP components after intake of theanine, an amino acid in tea leaves and its effect on stress response. Cell Mol Neurobiol. (2012)
• ^ a b c Tian X, et al. Protective effect of l-theanine on chronic restraint stress-induced cognitive impairments in mice. Brain Res. (2013)
• ^ Joëls M, et al. The coming out of the brain mineralocorticoid receptor. Trends Neurosci. (2008)
• ^ Sandi C. Glucocorticoids act on glutamatergic pathways to affect memory processes. Trends Neurosci. (2011)
• ^ Garcia R. Stress, hippocampal plasticity, and spatial learning. Synapse. (2001)
• ^ Coffee, green tea, black tea and oolong tea consumption and risk of mortality from cardiovascular disease in Japanese men and women.
• ^ Peters U, Poole C, Arab L. Does tea affect cardiovascular disease? A meta-analysis. Am J Epidemiol. (2001)
• ^ Lorenz M, et al. Green and black tea are equally potent stimuli of NO production and vasodilation: new insights into tea ingredients involved. Basic Res Cardiol. (2009)
• ^ a b Siamwala JH, et al. L-theanine promotes nitric oxide production in endothelial cells through eNOS phosphorylation. J Nutr Biochem. (2013)
• ^ a b c Owen GN, et al. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci. (2008)
• ^ Giesbrecht T, et al. The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutr Neurosci. (2010)
• ^ Foxe JJ, et al. Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task. Neuropharmacology. (2012)
• ^ Haskell CF, et al. The effects of L-theanine, caffeine and their combination on cognition and mood. Biol Psychol. (2008)
• ^ Einöther SJ, et al. L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness. Appetite. (2010)
• ^ a b c d e Intestinal transport of pure theanine and theanine in green tea extract: Green tea components inhibit theanine absorption and promote theanine excretion.
• ^ Varietal Differences in the Total and Enantiomeric Composition of Theanine in Tea.
• ^ Desai MJ, et al. Pharmacokinetics of theanine enantiomers in rats. Chirality. (2005)
• ^ Kitaoka S, et al. Transmural potential changes associated with the in vitro absorption of theanine in the guinea pig intestine. Biosci Biotechnol Biochem. (1996)
• ^ Kinetics of the sodium-dependent glutamine transporter in human intestinal cell confluent monolayers.
• ^ Fiermonte G, et al. Identification of the mitochondrial glutamate transporter. Bacterial expression, reconstitution, functional characterization, and tissue distribution of two human isoforms. J Biol Chem. (2002)
• ^ Borzelleca JF, Peters D, Hall W. A 13-week dietary toxicity and toxicokinetic study with l-theanine in rats. Food Chem Toxicol. (2006)
• ^ Mutagenicity test of food additives with Salmonella typhimurium TA97 and TA102. X.
• Sarris J, et al. L-theanine in the adjunctive treatment of generalized anxiety disorder: A double-blind, randomised, placebo-controlled trial. J Psychiatr Res. (2019)