Adhd and l theanine

L-theanine and Caffeine Improve Sustained Attention, Impulsivity and Cognition in Children with Attention Deficit Hyperactivity Disorders by Decreasing Mind Wandering (OR29-04-19)

  • Journal List
  • Curr Dev Nutr
  • PMC6574559

Curr Dev Nutr. 2019 Jun; 3(Suppl 1): nzz031.OR29-04-19.

Published online 2019 Jun 13. doi: 10.1093/cdn/nzz031.OR29-04-19

PMCID: PMC6574559

,1,2,1,1 and 1

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Our previous research corroborate the work of others to indicate that L-theanine and caffeine are known to improve sustained attention in healthy adults. The effects of these substances have not been studied in relation to attention deficit hyperactivity disorders (ADHD). We aimed to examine the effects of L-theanine, caffeine and their combination on sustained attention, impulse control and overall cognition in male children with ADHD in a four-way, placebo-controlled repeated measures crossover study.


Five male children (8–17) years with ADHD, who have responded to stimulants were recruited via advertisement. L-theanine (2.5 mg/kg body weight), caffeine (2.0 mg/kg body weight), their combination and a placebo were administered in a randomized crossover design on four separate days. Functional magnetic resonance imaging (fMRI) was performed 55 minutes post-dose, while the subjects engaged in a Go/NoGo continuous performance task (CPT) and a stop-signal reaction time (SSRT) task. NIH Cognition Toolbox was administered 110 minutes post-dose. Data were analyzed using two-level regression models constructed using R and FSL software to compare the three treatments vs. the placebo on all measured outcomes.


L-theanine, caffeine and their combination improved hit rate in CPT (p < 0. 001) and total cognition composite in NIH Cognition Toolbox (p < 0.05) compared to placebo. L-theanine and caffeine, when administered alone, increased SSRT (p = 0.007 and p = 0.018 respectively), while the combination decreased SSRT compared to placebo (p = 0.012). L-theanine, caffeine and the combination decreased task-related fMRI reactivity of the default mode network in the brain, which is known to show increased activity during mind wandering.


L-theanine, caffeine and their combination seem to improve sustained attention and overall cognitive performance in children with ADHD, possibly via decreasing mind wandering during exertion of attention. While L-theanine alone and caffeine alone seem to increase impulsivity, the combination seems to decrease (i.e., improve) impulsivity in children with ADHD. As such, the combination of L-theanine and caffeine may have the potential to be used as a therapeutic and/or dose sparing agent to manage symptoms in children with ADHD.

Funding Sources

Texas Tech Neuroimaging Institute.

Articles from Current Developments in Nutrition are provided here courtesy of American Society for Nutrition

L-Theanine for ADHD -

Theanine (L-theanine, 5-N-ethyl-L-glutamine, delta-glutamylethylamide; gamma-glutamylethylamide) is an amino acid found in green tea.1
Theanine passes the blood-brain barrier.2

  • 1. Neuropsiological effect of theanine
  • 2. Behavioral effect of theanine
  • 3. L-Theanine for ADHD

1. Neuropsiological effect of theanine¶

L-theanine acts neurophysiologically as:

  • Glutamate reuptake inhibitor3
    • Theanine acts strongly on the glutamine transporter and inhibits glutamine reuptake, which in turn suppressed the conversion of glutamine to glutamate by glutaminase.2
  • competitive low-affinity glutamate receptor antagonist in the hippocampus3
    • very weakly antagonistic to glutamate AMPA and glutamate kainate receptors. 2
  • binds to GABA-A receptors3
  • increased gene expression with large effect size4
    • in the hippocampus
      • EGR1 (Early growth response protein 1; also ZNF268 = Zinc finger protein 268 or NGFI-A = Nerve growth factor-induced protein A)
      • MAO-A (monoamine oxidase A; degrades serotonin, dopamine, and norepinephrine)
      • ANXA9 (Annexin A9)
      • S100a10 (Calcium-binding protein A10; P11)
      • GABRB2 (GABA-A receptor beta-2 subunit)
      • CHRM2 (Muscarinic Acetylcholine Receptor M2)
    • in the amygdala
      • GABRA4 (GABA-A receptor alpha-4 subunit)
      • SLC5A7 (high-affinity choline transporter; solute carrier family 5 member 7)
      • DRD2 (D2 dopamine receptor gene)
      • DRD1a (D1a dopamine receptor gene)
      • GLRA2 (glycine receptor alpha 2)
      • CHRNA6 (nicotinic receptor / choline receptor alpha 6)
      • HTR3A (serotonin 3A receptor)
      • CHRNB4 (nicotinic receptor / choline receptor beta 4)
      • GABRD (GABA-A receptor subunit delta)
      • PRIMA1 (Proline Rich Membrane Anchor 1)
      • CHRNA3 (nicotinic receptor / choline receptor alpha 3)

L-theanine is safe in daily doses of 200 to 400 mg for up to 8 weeks, he said. 5

2. Behavioral effect of theanine¶

Theanine has a sedative and relaxing effect,6 moreover this better than the benzodiazepine alprazolam, but not anxiolytic.7 According to other studies, theanine has anxiolytic and stress-inhibiting effects,5 whereby the anxiolytic effect does not appear to occur through action on the GABA-A receptor.8
Caffeine and gallate catechins, which are abundant in tea, inhibit the relaxing effects of theanine.9

Theanine inhibited the deterioration of cognitive functions in elderly subjects2 and may have parkinsonism-preventive effects due to neuroprotective effects.10

L-theanine administration promoted the release of dopamine and norepinephrine in mouse hippocampus and stimulated protein kinase A (PKA) phosphorylation. The long-term potentiation in the hippocampus improved by L-theanine in an Alzheimer’s disease mouse model could be impaired by a PKA inhibitor. It is likely that L-theanine improves memory and long-term potentiation in the hippocampus of Alzheimer’s disease mice via the dopamine D-1/D-5 receptor PKA pathway. L-theanine may be considered as a candidate for the treatment of Alzheimer’s disease.11

Theanine counteracted a caffeine-induced increase in blood pressure but had no effect on mood.12

3. L-Theanine for ADHD¶

Apparently, theanine increases dopamine levels in the striatum. Except for improved learning abilities, the behavior of mice receiving theanine for 3 months was unchanged.13

Direct theanine administration into the striatum of mice significantly increased dopamine in a dose-dependent manner. The dopamine increase was attenuated by a previously given calcium-free ring buffer. If the ring buffer also contained the non-NMDA glutamate receptor antagonist MK-801, the significant dopamine increase by L-theanine was maintained. When an NMDA glutamate receptor antagonist was given instead, this significantly inhibited theanine-induced dopamine release in the striatum. Theanine altered the concentrations of norepinephrine, 3,4-dihydroxyphenylacetic acid (DOPAC), and 5-hydroxyindoleacetic acid (5HIAA) only in the striatum but not in other brain regions.
Theanine caused a significant increase in serotonin and dopamine in the brain, especially in striatum, hypothalamus and hippocampus.14

A very small study of 5 boys with ADHD examined the effects of L-theanine (2.5 mg/kg) and caffeine (2.0 mg/kg) (alternative, combined, and versus placebo):15

L-Theanine alone

  • improved overall cognition
  • tend to worsen inhibitory control (increased stop-signal reaction time)

Caffeine alone

  • worsens the inhibitory control

L-theanine and caffeine combined

  • improved overall cognitive performance
  • improved the signal sensitivity to the Go signal (the d-prime in the Go/NoGo task)
  • tended to improve inhibitory control
  • decreased task-related reactivity of the default mode network associated with mind wandering

A randomized placebo-controlled trial found improved directed attention with L-theanine and even more so with a combination of L-theanine with caffeine. 16

400 mg L-theanine (200 mg each in the morning and at noon) improved sleep quality in a randomized, double-blind, placebo-controlled study in boys with ADHD. Actigraph measures showed a significantly higher percentage of sleep and sleep efficiency achieved, along with a nonsignificant trend toward less activity during sleep. Sleep latency and other sleep parameters remained unchanged. No significant adverse events occurred.17

There are no studies on the use of L-theanine in relation to other ADHD symptoms.

  1. Alramadhan, Hanna, Hanna, Goldstein, Avila, Weeks (2012): Dietary and botanical anxiolytics. Med Sci Monit. 2012 Apr;18(4):RA40-8. ↥

  2. Kakuda (2011): Neuroprotective effects of theanine and its preventive effects on cognitive dysfunction. Pharmacol Res. 2011 Aug;64(2):162-8. doi: 10.1016/j.phrs.2011.03.010. ↥ ↥ ↥ ↥

  3. Anas Sohail, Ortiz, Varghese, Fabara, Batth, Sandesara, Sabir, Khurana, Datta, Patel (2021): The Cognitive-Enhancing Outcomes of Caffeine and L-theanine: A Systematic Review. Cureus. 2021 Dec 30;13(12):e20828. doi: 10.7759/cureus.20828. PMID: 35111479; PMCID: PMC8794723. REVIEW ↥ ↥ ↥

  4. Ceremuga, Martinson, Washington, Revels, Wojcicki, Crawford, Edwards, Kemper, Townsend, Herron, Ceremuga, Padron, Bentley (2014)_- : Effects of L-theanine on posttraumatic stress disorder induced changes in rat brain gene expression. ScientificWorldJournal. 2014;2014:419032. doi: 10.1155/2014/419032. PMID: 25165739; PMCID: PMC4137547. ↥

  5. Lopes Sakamoto, Metzker Pereira Ribeiro, Amador Bueno, Oliveira Santos (2019): Psychotropic effects of L-theanine and its clinical properties: From the management of anxiety and stress to a potential use in schizophrenia. Pharmacol Res. 2019 Sep;147:104395. doi: 10.1016/j.phrs.2019.104395. PMID: 31412272. REVIEW ↥ ↥

  6. Weeks (2009): Formulations of dietary supplements and herbal extracts for relaxation and anxiolytic action: Relarian. Med Sci Monit. 2009 Nov;15(11):RA256-62. ↥

  7. Lu, Gray, Oliver, Liley, Harrison, Bartholomeusz, Phan, Nathan (2004): The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans. Hum Psychopharmacol. 2004 Oct;19(7):457-65. ↥

  8. Heese, Jenkinson, Love, Milam, Perkins, Adams, McCall, Ceremuga (2009): Anxiolytic effects of L-theanine–a component of green tea–when combined with midazolam, in the male Sprague-Dawley rat. AANA J. 2009 Dec;77(6):445-9. ↥

  9. Unno, Yamada, Iguchi, Ishida, Iwao, Morita, Nakamura (2017): Anti-stress Effect of Green Tea with Lowered Caffeine on Humans: A Pilot Study. Biol Pharm Bull. 2017;40(6):902-909. doi: 10.1248/bpb.b17-00141. PMID: 28566632. ↥

  10. Cho, Kim, Lee, Park, Kim, Chun (2008): 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. ↥

  11. Zhu, Yang, Xie, Wan (2018): Synaptic modification by L-theanine, a natural constituent in green tea, rescues the impairment of hippocampal long-term potentiation and memory in AD mice. Neuropharmacology. 2018 Aug;138:331-340. doi: 10.1016/j.neuropharm.2018.06.030. ↥

  12. Rogers, Smith, Heatherley, Pleydell-Pearce (2008): Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. Psychopharmacology (Berl). 2008 Jan;195(4):569-77. ↥

  13. Yokogoshi, Terashima (2000): Effect of theanine, r-glutamylethylamide, on brain monoamines, striatal dopamine release and some kinds of behavior in rats. Nutrition. 2000 Sep;16(9):776-7. ↥

  14. Yokogoshi, Kobayashi, Mochizuki, Terashima (1998): Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats. Neurochem Res. 1998 May;23(5):667-73. ↥

  15. Kahathuduwa, Wakefield, West, Blume, Dassanayake, Weerasinghe, Mastergeorge (2020): Effects of L-theanine-caffeine combination on sustained attention and inhibitory control among children with ADHD: a proof-of-concept neuroimaging RCT. Sci Rep. 2020 Aug 4;10(1):13072. doi: 10.1038/s41598-020-70037-7. PMID: 32753637; PMCID: PMC7403383. ↥

  16. Kahathuduwa, Dhanasekara, Chin, Davis, Weerasinghe, Dassanayake, Binks (2018): l-Theanine and caffeine improve target-specific attention to visual stimuli by decreasing mind wandering: a human functional magnetic resonance imaging study. Nutr Res. 2018 Jan;49:67-78. doi: 10.1016/j.nutres.2017.11.002. Epub 2017 Nov 16. PMID: 29420994. ↥

  17. Lyon, Kapoor, Juneja (2011): 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 Dec;16(4):348-54. PMID: 22214254. ↥

L-theanine: A nutrient in green tea with powerful healing properties

The information in this blog has not been verified by your country's public health authority and is not intended as a diagnosis, treatment, or medical advice. More

What is L-theanine?

L-theanine (Camellia sinensis) is a unique amino acid found almost exclusively in tea plants. As a dietary supplement, it is a popular natural way to relieve stress and calm, while also boosting mental energy. nine0009 1

Green tea leaves contain 1 to 4% L-theanine by dry weight. It has also been available as a dietary supplement for nearly 30 years. As such, it first gained popularity in Japan in 1994 when an L-theanine supplement was approved for use as a stress reliever and relaxation aid. Its popularity has spread to North America, and L-theanine can now be found as an essential ingredient in functional foods, beverages, and supplements designed to provide mental and physical relaxation without causing drowsiness. nine0003

Another important benefit of L-theanine is its rapid action. Usually the effect is felt within the first 30 minutes and lasts from 8 to 12 hours. L-theanine is recognized as a generally safe ingredient (has a GRAS label from the US Food and Drug Administration) and no side effects have been reported. 1-3

L-theanine in green tea

Any discussion of the benefits of green tea would be incomplete without mentioning L-theanine. The tea plant uses L-theanine to produce polyphenols known as catechins through photosynthesis. Theanine is also responsible for the characteristic flavor and aroma of green tea. nine0003

As for the different types of green tea, matcha has a high theanine content, as its cultivation involves shading the tea bushes during the last three weeks before harvest. As a result, less intense photosynthesis occurs and more theanine remains in the leaves, which gives matcha tea its characteristic sweetness and aroma. Shading also causes chlorophyll to build up in the leaves of the plant, giving matcha a brighter green color.

While traditional green tea may have as little as 5 mg of theanine per cup, shade-grown teas such as matcha can have up to nine times the theanine content in one cup, which is about 45 mg, but more often in total, matcha contains 25 to 30 mg of theanine per cup. When it comes to caffeine, matcha contains only 30mg per cup. Thus, in general, matcha contains equal amounts of caffeine and theanine. nine0003

Research-Backed Benefits of L-Theanine

Human clinical studies have confirmed many of L-theanine's unique benefits as it has been shown to reduce the side effects of caffeine, such as anxiety and irritability. Studies have also demonstrated its ability to reduce feelings of stress, improve sleep quality, combat symptoms of premenstrual syndrome, increase mental sharpness and help with attention deficit hyperactivity disorder. nine0003

L-Theanine Brain Benefits

L-theanine has been shown to have amazing effects that primarily relate to brain chemistry. It is easiest to think of theanine as an "anti-caffeine" molecule, but its action is not limited to this. Caffeine is a stimulant, and theanine moderates some of its effects on the brain. But it is wrong to think of theanine as a sedative. L-theanine is definitely not a sedative, as it stimulates the brain, it just does it differently than caffeine. nine0009 1-3

L-theanine has been shown in animal models to increase levels of many different brain chemicals, especially neurotransmitters that transmit signals from one brain cell to another. In these studies, it has been shown to improve brain function, learning ability, and memory. This is probably why theanine-rich forms of green tea, such as matcha, have always been so prized as meditation aids and considered an important part of green tea ceremonies. nine0003

One of the most important results of the complex action of theanine in the brain is an increase in the production of alpha waves. 4 These waves are associated with a feeling of calmness and concentration. During meditation, the brain produces a large number of alpha waves. It is interesting to note that, more than other forms of green tea valued by ancient Japanese monks for tea ceremonies, matcha is the richest source of theanine, while being low in caffeine. Theanine enhances the meditative state, promoting greater mental focus and alertness. In addition to increasing alpha waves in the brain, theanine also reduces beta wave activity. This brain rhythm has been associated with nervousness, erratic thoughts, and hyperactivity. nine0003

L-theanine and stress management

L-theanine is able to induce positive changes in brain chemistry, increase alpha wave activity and decrease beta wave activity, resulting in less stress and anxiety, and less irritability and anxiety. 1-3 However, when used with caffeine, theanine has been shown to improve cognition, concentration, and visual processing, as well as increase accuracy when switching from one task to another. All the positive effects of L-theanine. nine0009 4-6

L-theanine is mainly used to reduce stress and anxiety without causing drowsiness. As mentioned above, L-theanine promotes a state of calm, mindful wakefulness.

L-theanine, ADHD and sleep

This property of L-theanine means that it may be useful for attention deficit hyperactivity disorder (ADHD). The Canadian Center for Functional Medicine, in collaboration with the University of British Columbia, conducted a double-blind, placebo-controlled study of boys aged 8-12 years with a diagnosis of ADHD who took 200 mg of L-theanine twice daily in a chewable tablet. nine0009 7 Primary results of the study showed that L-theanine was safe and effective for the subjects and improved the quality of sleep, helping them sleep more soundly, which is very important for children with ADHD. Sleep disturbance is a significant factor in ADHD in children.

Another study also showed that L-theanine may improve sleep quality. 1.2 It is not a sedative (sleeping pill) per se, but helps to sleep by promoting a more relaxed state of mind. nine0003

L-theanine may have additional benefits for ADHD. A study published in 2020 analyzed in great detail the effects of a single dose of L-theanine (2.5 mg per kg of body weight), caffeine (2 mg per kg of body weight), and a combination of the two on brain function in boys 8 -15 years with ADHD versus placebo. The study also included functional magnetic resonance imaging (fMRI) to assess the effect of L-theanine on the functioning of brain neural networks. The combined results suggest that the combination of L-theanine and caffeine may be a possible treatment option for ADHD-related impairments in sustained attention, inhibitory control, and overall cognition. nine0009 8

The researchers suggested that taking a combination of L-theanine and caffeine in the morning “may be more beneficial for other aspects of ADHD, such as impaired attention and hyperactivity.” 8

Several other studies have shown that the combination of L-theanine and caffeine (eg 97 mg and 40 mg respectively) can significantly improve certain mental performance and alertness in adults. 4-6

L-theanine and mental enhancement

L-theanine itself improves brain function. 1.2 This was clearly demonstrated in a 2021 double-blind study in which a single dose of 100 mg of L-theanine and a daily dose of 100 mg for 12 weeks significantly improved brain function. The study involved men and women aged 50 to 69 years. 9 A series of tests known as Cognitrax were used to assess cognitive function. The evaluation was carried out before the start of treatment, after a single dose and after 12 weeks of regular use of L-theanine. The results showed that L-theanine helped reduce reaction time on attention tasks, increase the number of correct answers, and reduce gap errors on working memory tasks. These results are due to the fact that L-theanine redistributes attention resources to effectively improve mental focus. The researchers concluded that L-theanine may help increase attention, thereby improving working memory and executive functions of the brain. nine0003

Earlier studies have shown that L-theanine as a single agent improves certain mental functions with continued use. However, it is difficult to separate the direct effect of L-theanine from the indirect effect of reducing the negative effects of stress and lack of sleep on cognition. For example, in one study, participants took L-theanine (200 mg per day) or placebo tablets for four weeks. 10 Results analysis included assessment of depression, anxiety, sleep quality, and a set of psychological tests. The results showed a significant improvement in sleep and mood, as well as improvements in cognition, verbal fluency, and performance measures. The results confirmed that improvements in cognitive function are closely associated with improvements in sleep and mood. nine0003

How L-Theanine Works

L-theanine is absorbed and delivered to the brain across the blood-brain barrier, promoting a relaxed state with greater mental clarity and focus. It helps achieve this state by increasing brain levels of critical neurotransmitters such as dopamine, serotonin, and gamma-aminobutyric acid (GABA), while counteracting the effect of the excitatory neurotransmitter glutamate. 1.2

L-theanine also has an anti-inflammatory effect on brain cells and may protect them from stress and age-related damage. nine0003

One of the most important immediate effects noted with L-theanine is an increase in alpha brain wave activity, which is referred to as a “relaxed wakefulness” state, while reducing beta wave activity, characteristic of nervousness, erratic thoughts and perspective Model brain rhythm, supported by L-theanine, is associated with the state of mind during meditation, relaxed concentration of the mind and creativity. Again, this effect explains the use of matcha in the tea ceremony by Japanese monks to enhance meditation. nine0009 4

Another benefit of L-theanine is that it helps fight stress by lowering cortisol levels. This effect is of great importance, since increased levels of cortisol and related stress hormones can affect memory and learning. 3

How L-theanine works in the body
  • Increases levels of serotonin, dopamine and gamma-aminobutyric acid in the brain
  • Counteracts some of the stimulant effects of caffeine
  • Provides mental and physical relaxation without causing drowsiness
  • Improves learning ability and memory as confirmed by human and animal studies
  • Positive results in double-blind studies showing the following:
    • Reduced feelings of stress
    • Improved sleep quality
    • Decreased symptoms of premenstrual syndrome
    • Increased production of alpha brain waves
    • Decreased production of beta brain waves

L-theanine dosage

Based on the results of numerous clinical studies, L-theanine has been found to be effective at doses ranging from 100 to 200 mg per day. Although L-theanine does not have any known side effects, it is recommended that you take no more than 600 mg in 6 hours and no more than 1200 mg in 24 hours.

At doses of 100 to 200 mg, L-theanine does not have a sedative effect, but significantly improves the quality of sleep. It is also an excellent synergist for melatonin and 5-hydroxytryptophan (5-HTP) to improve sleep quality. nine0003

Safety and drug interactions

L-theanine is safe and has no side effects as proven by numerous safety studies and clinical trials. 1.2 In addition, since 1994, L-theanine has been consumed in beverages, foods, and supplements with no evidence of adverse reactions or contraindications. L-theanine, also known as Suntheanine, received the US Food and Drug Administration's GRAS label in 2007 for use in food and beverages and as a dietary supplement. nine0003

No side effects have been reported with L-theanine drug interactions. L-theanine may contribute to the action of anti-anxiety and antipsychotic medications. For example, a 2011 study published in the Journal of Clinical Psychiatry clearly showed the benefit of L-theanine in improving the effectiveness of psychiatric drugs. In this study, 60 patients with schizophrenia took 400 mg L-theanine per day in addition to their current antipsychotic medication for more than 2.5 years. nine0009 11 Compared with placebo, the inclusion of L-theanine resulted in a significant reduction in anxiety and psychiatric symptoms. L-theanine has been found to be safe and has not shown any side effects when interacting with medications.


  1. Williams JL, Everett JM, D'Cunha NM, et al. The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review. Plant Foods Hum Nutr. 2020;75(1):12-23. nine0114
  2. Türközü D, Şanlier N. L-theanine, unique amino acids of tea, and its metabolism, health effects, and safety. Crit Rev Food Sci Nutr. 2017;57(8):1681-1687.
  3. Kimura K, Ozeki M, Juneja L.R., Ohira H. L-Theanine reduces psychological and physiological stress responses. Biol Psychol. 2007;74(1):39-45.
  4. Kobayashi k, Nagato Y, Aoi N, et al. Effects of l-theanine on the release of α-brain waves in human volunteers. Nippon Nogeikagaku Kaishi 1998;72:153–157.
  5. Dodd FL, Kennedy DO, Riby LM, Haskell-Ramsay CF. A double-blind, placebo-controlled study evaluating the effects of caffeine and L-theanine both alone and in combination on cerebral blood flow, cognition and mood. Psychopharmacology (Berl). 2015;232(14):2563-2576. nine0114
  6. Giesbrecht T, Rycroft JA, Rowson MJ, De Bruin EA. The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutr Neurosci. 2010;13(6):283-290.
  7. Lyon MR, Kapoor MP, Juneja L.R. 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;16(4):348-354.
  8. Kahathuduwa CN, Wakefield S, West B.D., et al. Effects of L-theanine-caffeine combination on sustained attention and inhibitory control among children with ADHD: a proof-of-concept neuroimaging RCT. sci rep. 2020;10(1):13072. nine0114
  9. Baba Y, Inagaki S, Nakagawa S, et al. Effects of l-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study. J Med Food. 2021;24(4):333-341.
  10. Hidese S, Ogawa S, Ota M, et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019;11(10):2362.
  11. Ritsner MS, Miodownik C, Ratner Y, 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;72(1):34-42. nine0114

L-theanine - a quick guide - Blog

The information in this blog has not been verified by your country's public health authority and is not intended as a diagnosis, treatment, or medical advice. Read more

Daily stress has become a normal part of modern life. Pressure at work, family conflicts, financial pressure, the number of cars on the road and time management are just some of the "stressors" we face on a daily basis. For some people, stress can be overwhelming, leading to feelings of anxiety and insomnia. Fortunately, there are safe and effective natural approaches that provide immediate results when we feel exhausted. One of the top recommendations is L-theanine. nine0003

L-theanine, a unique amino acid found almost exclusively in plants of the tea family ( Camellia sinensis ), is one of nature's best compounds for relieving stress and anxiety. L-theanine is the main amino acid in green tea, accounting for 1-2% of the dry weight of tea leaves. The highly purified forms of L-theanine used in dietary supplements are produced through a fermentation process that mimics the natural process found in green tea leaves. nine0003

L-theanine: a mild, natural stress reliever

The effects achieved with L-theanine are simply amazing. Clinical studies have shown that L-theanine reduces stress, improves sleep quality, reduces PMS symptoms, improves visual acuity, and reduces the negative side effects of caffeine. These clinical effects are directly related to L-theanine's ability to stimulate alpha brain wave activity. The drug helps people to stay calm, focused, focused and brain energy. It also reduces the activity of beta waves associated with nervousness, scattered thoughts and hyperactivity. nine0003

In Japan, L-theanine has been approved for use for decades as an aid in coping with stress and promoting relaxation. It is a very popular ingredient in Japanese functional foods and drinks, as well as dietary supplements designed to provide mental and physical relaxation without the effect of drowsiness. L-theanine is a fast acting remedy. Typically, effects are felt within the first 30 minutes and have been shown to last up to 8-12 hours. nine0003

At standard doses, eg 100-200 mg, L-theanine does not act as a sedative, but significantly improves the quality of sleep. In one double-blind study, L-theanine 200 mg was shown to result in statistically significant improvements in sleep efficiency, a measure of actual sleep time between the time you fall asleep and nocturnal awakenings.

L-theanine - a special brain booster for children

Just like adults, children are exposed to stress and pressure every day. Temporary, minor stress does no harm, and most children do well with it. On the contrary, long-term daily minor stresses accumulate and become just as devastating as major stressful events, wreaking havoc on physical, emotional and mental health. A general sense of insecurity can cause children to experience increased levels of anxiety and depression. nine0003

L-theanine stimulates the production of alpha brain waves and also suppresses beta waves (associated with nervousness, scattered thoughts and hyperactivity). This is especially helpful in helping children who have trouble falling asleep and staying asleep because their head refuses to turn off at night.

Learn more