Is L-Theanine a Natural Nootropic?

In this article, you will learn about the amazing health benefits of L-theanine, one of the ingredients in our Seneca Nootropic Complex. You will discover how it can reduce stress and anxiety while enhancing brain health and cognitive function.

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What is L-Theanine?

L-theanine is an amino acid found naturally in all teas and certain plant extracts, with the highest concentration found in green tea. The theanine content in green tea is believed to be the primary reason people experience relaxation after consuming it. Additionally, L-theanine is commonly used as a supplement to help individuals manage stress and reduce anxiety (1).

This reduction in stress enables individuals taking theanine to experience decreased inflammation, improved sleep quality, and enhanced cognitive clarity.

How Does L-Theanine Work?

One of the primary mechanisms by which L-theanine operates is through its ability to regulate the levels of a neurotransmitter known as glutamate. Glutamate primarily serves as an excitatory neurotransmitter, activating brain functions crucial for focus, learning, and memory.

Reduced Glutamate Toxicity

In today's world, most people have access to more than enough calories, which correlates with excessive glutamate levels. When combined with chronic stress and inflammation, this surplus can lead to over-activation of glutamate receptors in the brain.

This excess activation may become toxic to brain cells, also known as neurons, potentially resulting in various issues such as poor sleep, hyperactivity, and stress, as well as more serious conditions like depression and dementia.

Through a process called competitive inhibition, theanine reduces excessive levels of glutamate by binding to the same sites on neurons. By doing this, theanine inhibits glutamate's capacity to activate neurons and become toxic (2, 3).

Theanine also lessens the uptake of glutamine into neurons, providing an additional mechanism to mediate excess glutamate levels (4).

Increased GABA and Glycine

Besides reducing excess glutamate levels in the brain, theanine also enhances the levels of the neurotransmitters GABA and glycine.

Both GABA and glycine are inhibitory neurotransmitters, counteracting the excitatory effects of glutamate. GABA, for instance, promotes feelings of calm and relaxation (5, 6).

By elevating GABA and glycine levels, theanine fosters a calming effect on the brain and central nervous system.

Increased Levels of BDNF

Research indicates that theanine also elevates levels of BDNF (brain-derived neurotrophic factor), a growth hormone for the brain that aids in neuronal growth and repair, as well as synaptic plasticity, which is vital for forming new connections and learning (7).

Serotonin and Dopamine

L-theanine can enhance levels of serotonin and dopamine in the brain (8). These neurotransmitters play crucial roles in motivation, focus, learning, and overall well-being. Low levels of these neurotransmitters have been linked to anxiety and depression.

Increased Alpha Brain Waves

Studies have shown that theanine can increase alpha brainwave levels (9, 10). Alpha brainwaves are associated with relaxed focus, improved concentration, and enhanced cognitive function.

Show Me the Science!

Reduced Stress

A Japanese study involved 12 subjects undergoing a challenging mental arithmetic test. Participants were given 200 mg of theanine either at the start or midway. These results were compared to controls without supplementation and those receiving a placebo.

Findings indicated lower heart rates and reduced salivary immunoglobulin A levels in participants who consumed theanine (11). Immunoglobulin A is an antibody whose production increases during stress.

Another study involving 34 subjects on a cognitive stress test found that participants who took 200 mg of theanine exhibited lower salivary cortisol levels (12).

Reduced Anxiety

In one study, 400 mg of L-theanine per day was administered to patients with schizophrenia alongside their usual medication, while a different group received a placebo. After eight weeks, the patients taking theanine showed reduced anxiety, lower cortisol levels, decreased dysphoric mood, and increased BDNF levels (13).

Depression

In another study, 20 patients with major depressive disorder were given 250 mg of theanine daily for eight weeks alongside their existing medication. At the conclusion, the patients had lower depression scores, reduced anxiety, improved sleep quality, and enhanced cognitive function and memory scores (14).

Reduced Blood Pressure

Caffeine is known to raise blood pressure; however, consuming theanine together with caffeine can mitigate this increase (15). Another study demonstrated that theanine prevented blood pressure spikes induced by cognitive tests designed to provoke stress responses (16).

L-Theanine Helps Improve Memory

L-theanine is an ingredient in our Seneca Nootropic Complex. In a randomized, double-blind study involving 91 subjects with mild cognitive impairment—the first stage of dementia symptoms—participants took L-theanine for 16 weeks.

At the end of the study, those who took theanine performed better on memory tests than the placebo group. They also exhibited increased theta brain waves, associated with heightened cognitive awareness (17).

Alzheimer's Disease

Beyond mild cognitive impairment, further research explored the effects of L-theanine supplementation in a mouse model of Alzheimer's disease. Researchers injected amyloid beta proteins, which form amyloid plaques in Alzheimer's patients, into the brains of mice. This process led to neuronal cell death and memory impairment.

Half the mice received L-theanine in their drinking water for five weeks, resulting in better performance on memory tests compared to those that did not receive the supplement. Brain dissections revealed less neuronal cell death and oxidative damage in the theanine group, as well as higher levels of the main antioxidant, glutathione, indicating improved antioxidant production.

While such studies cannot be directly replicated in humans due to ethical concerns, they provide promising results that may inspire further research into the effects of theanine on Alzheimer's patients (18).

Improved Sleep

A placebo-controlled trial involving 98 boys aged 8 to 12 with ADHD focused on whether L-theanine could enhance sleep quality, which is often compromised in ADHD. Half of the participants were given 100 mg of theanine daily for six weeks. Researchers observed increased sleep percentages and improved sleep efficiency in the group that supplemented with theanine (19).

Another study involving 17 patients with schizophrenia, supplemented with 250 mg of theanine daily for eight weeks, also found improved sleep quality among participants (20).

Final Thoughts

The benefits of L-theanine extend beyond merely reducing stress and anxiety. It can also enhance focus, learning, memory, and more. Given its scientifically supported advantages for brain health, we have included L-theanine in our Seneca Nootropic Complex.

Seneca is a non-stimulating nootropic and cognitive-enhancing supplement. Each serving contains 200 mg of L-theanine HCL, along with 17 other natural nootropics designed to promote mental health and restful sleep.

Related article: Seneca Nootropic Complex 101: What Makes This Nootropic Stack So Good?

References

(1) Psychotropic effects of L-theanine and its clinical properties: From the management of anxiety and stress to a potential use in schizophrenia, Filipe Lopes Sakamoto, Rodrigo Metzker Pereira Ribeiro, Allain Amador Bueno, Heitor Oliveira Santos, Pharmacol Res, Sep;147:.

(2) Neurobiological effects of the green tea constituent theanine and its potential role in the treatment of psychiatric and neurodegenerative disorders, Anne L Lardner, Nutr Neurosci, Jul;17(4):145-55.

(3) The neuropharmacology of L-theanine (N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent, Pradeep J Nathan, Kristy Lu, M Gray, C Oliver, J Herb Pharmacother, ;6(2):21-30.

(4) Neuroprotective effects of the green tea components theanine and catechins, Takami Kakuda, Biol Pharm Bull, Dec;25(12):-8.

(5) Influence of alkylamides of glutamic acid and related compounds on the central nervous system. I. Central depressant effect of theanine, R Kimura, T Murata, Chem Pharm Bull (Tokyo), Jun;19(6):-61.

(6) Effects of theanine, r-glutamylethylamide, on neurotransmitter release and its relationship with glutamic acid neurotransmission, Takashi Yamada, Takehiko Terashima, Tsutomu Okubo, Lekh Raj Juneja, Hidehiko Yokogoshi, Nutr Neurosci, Aug;8(4):219-26.

(7) Behavioral and molecular evidence for psychotropic effects in L-theanine, Chisato Wakabayashi, Tadahiro Numakawa, Midori Ninomiya, Shuichi Chiba, Hiroshi Kunugi, Psychopharmacology (Berl), Feb;219(4):-109.

(8) L-theanine, unique amino acid of tea, and its metabolism, health effects, and safety, Duygu Türközü, Nevin Şanlier, Crit Rev Food Sci Nutr, May 24;57(8):-.

(9) L-theanine, a natural constituent in tea, and its effect on mental state, Anna C Nobre, Anling Rao, Gail N Owen, Asia Pac J Clin Nutr, ;17 Suppl 1:167-8.

(10) Effects of Theanine on the Release of Brain Alpha Wave in Adult Males, Song CH, Jung JH, Oh JS, Kim KS, Korean J Nutr, Nov;36(9):918-923.

(11) L-Theanine reduces psychological and physiological stress responses, Kenta Kimura, Makoto Ozeki, Lekh Raj Juneja, Hideki Ohira, Biol Psychol, Jan;74(1):39-45.

(12) Anti-Stress, Behavioral, and Magnetoencephalography Effects of an L-Theanine-Based Nutrient Drink: A Randomised, Double-Blind, Placebo-Controlled, Crossover Trial, David J White, Suzanne de Klerk, Nutrients, Jan 19;8(1):53.

(13) Serum levels of brain-derived neurotrophic factor and cortisol to sulfate of dehydroepiandrosterone molar ratio associated with clinical response to L-theanine as augmentation of antipsychotic therapy in schizophrenia and schizoaffective disorder patients, Chanoch Miodownik, Rachel Maayan, Yael Ratner, Vladimir Lerner, Leonid Pintov, Maria Mar, Abraham Weizman, Michael S Ritsner, Clin Neuropharmacol, Jul-Aug;34(4):155-60.

(14) Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study, Shinsuke Hidese, Miho Ota, Acta Neuropsychiatr, Apr;29(2):72-79.

(15) Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together, Peter J Rogers, Jessica E Smith, Susan V Heatherley, C W Pleydell-Pearce, Psychopharmacology (Berl), Jan;195(4):569-77.

(16) Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses, Ai Yoto, Mao Motoki, Sato Murao, Hidehiko Yokogoshi, J Physiol Anthropol, Oct 29;31(1):28.

(17) 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, Sang-Ki Park, In-Chul Jung, Won Kyung Lee, Young Sun Lee, Hyoung Kook Park, Hyo Jin Go, Kiseong Kim, Nam Kyoo Lim, Jin Tae Hong, Sun Yung Ly, Seok Seon Rho, J Med Food, Apr;14(4):334-43.

(18) 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, Tae Il Kim, Yong Kyung Lee, Sang Gi Park, Im Seop Choi, Jung Ok Ban, Hyoung Kook Park, Sang-Yoon Nam, Young Won Yun, Sang Bae Han, Ki Wan Oh, Jin Tae Hong, Free Radic Biol Med, Dec 1;47(11):-10.

(19) 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, Michael R Lyon, Mahendra P Kapoor, Lekh R Juneja, Altern Med Rev, Dec;16(4):348-54.

(20) Effect of L-theanine on glutamatergic function in patients with schizophrenia, Miho Ota, Chisato Wakabayashi, Acta Neuropsychiatr, Oct;27(5):291-6.

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