THEANINE - Uses, Side Effects, and More

Egashira, N., Ishigami, N., Pu, F., Mishima, K., Iwasaki, K., Orito, K., Oishi, R., and Fujiwara, M. Theanine prevents memory impairment induced by repeated cerebral ischemia in rats. Phytother.Res ;22(1):65-68. View abstract.

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Giesbrecht, T., Rycroft, J. A., Rowson, M. J., and De Bruin, E. A. The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutr Neurosci. ;13(6):283-290. View abstract.

Haskell, C. F., Kennedy, D. O., Milne, A. L., Wesnes, K. A., and Scholey, A. B. The effects of L-theanine, caffeine and their combination on cognition and mood. Biol.Psychol. ;77(2):113-122. View abstract.

Kakuda, T. Neuroprotective effects of the green tea components theanine and catechins. Biol Pharm Bull ;25(12):-. View abstract.

Kakuda, T., Nozawa, A., Sugimoto, A., and Niino, H. Inhibition by theanine of binding of [3H]AMPA, [3H]kainate, and [3H]MDL 105,519 to glutamate receptors. Biosci.Biotechnol.Biochem. ;66(12):-. View abstract.

Kamath, A. B., Wang, L., Das, H., Li, L., Reinhold, V. N., and Bukowski, J. F. Antigens in tea-beverage prime human Vgamma 2Vdelta 2 T cells in vitro and in vivo for memory and nonmemory antibacterial cytokine responses. Proc Natl.Acad.Sci U.S.A 5-13-;100(10):-. View abstract.

Kimura, K., Ozeki, M., Juneja, L. R., and Ohira, H. L-Theanine reduces psychological and physiological stress responses. Biol Psychol. ;74(1):39-45. View abstract.

Matsumoto, K., Yamada, H., Takuma, N., Niino, H., and Sagesaka, Y. M. Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial. BMC.Complement Altern.Med. ;11:15. View abstract.

Rogers, P. J., Smith, J. E., Heatherley, S. V., and Pleydell-Pearce, C. W. Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. Psychopharmacology (Berl) ;195(4):569-577. View abstract.

Sadzuka, Y., Sugiyama, T., Suzuki, T., and Sonobe, T. Enhancement of the activity of doxorubicin by inhibition of glutamate transporter. Toxicol.Lett 9-15-;123(2-3):159-167. View abstract.

Sugiyama, T. and Sadzuka, Y. Theanine and glutamate transporter inhibitors enhance the antitumor efficacy of chemotherapeutic agents. Biochim.Biophys.Acta 12-5-;(2):47-59. View abstract.

Sugiyama, T. and Sadzuka, Y. Theanine, a specific glutamate derivative in green tea, reduces the adverse reactions of doxorubicin by changing the glutathione level. Cancer Lett. 8-30-;212(2):177-184. View abstract.

Sugiyama, T., Sadzuka, Y., Nagasawa, K., Ohnishi, N., Yokoyama, T., and Sonobe, T. Membrane transport and antitumor activity of pirarubicin, and comparison with those of doxorubicin. Jpn J Cancer Res ;90(7):775-780. View abstract.

Terashima, T., Takido, J., and Yokogoshi, H. Time-dependent changes of amino acids in the serum, liver, brain and urine of rats administered with theanine. Biosci.Biotechnol.Biochem. ;63(4):615-618. View abstract.

Yang, Q. S., Xu, P. X., Li, Y. H., Jiang, S., Zhang, X., and Xue, M. [Effects of theanine and houpu extract in 7-day chick social separation-stress procedure]. Zhongguo Zhong.Yao Za Zhi. ;32(19):-. View abstract.

Yokogoshi, H., Kato, Y., Sagesaka, Y. M., Takihara-Matsuura, T., Kakuda, T., and Takeuchi, N. Reduction effect of theanine on blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats. Biosci.Biotechnol.Biochem. ;59(4):615-618. View abstract.

Baba Y, Inagaki S, Nakagawa S, Kaneko T, Kobayashi M, Takihara T. Effects of l-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study. J Med Food ;24(4):333-341. View abstract.

Baba Y, Takihara T, Okamura N. Theanine maintains sleep quality in healthy young women by suppressing the increase in caffeine-induced wakefulness after sleep onset. Food Funct ;14(15):-. View abstract.

Brennan BP, Admon R, Perriello C, et al. Acute change in anterior cingulate cortex GABA, but not glutamine/glutamate, mediates antidepressant response to citalopram. Psychiatry Res Neuroimaging. Nov 30;269:9-16. View abstract.

Camfield DA, Stough C, Farrimond J, Scholey AB. Actue effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis. Nutr Rev. ;72(8):507-522. View abstract.

Dassanayake TL, Wijesundara D, Kahathuduwa CN, Weerasinghe VS. Dose-response effect of L-theanine on psychomotor speed, sustained attention, and inhibitory control: a double-blind, placebo-controlled, crossover study. Nutr Neurosci . View abstract.

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. ;232(14):-. View abstract.

Einöther SJ, Martens VE, Rycroft JA, De Bruin EA. L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness. Appetite ;54(2):406-9. View abstract.

Evans M, McDonald AC, Xiong L, Crowley DC, Guthrie N. A Randomized, Triple-Blind, Placebo-Controlled, Crossover Study to Investigate the Efficacy of a Single Dose of AlphaWave(R) L-Theanine on Stress in a Healthy Adult Population. Neurol Ther ;10(2):-. View abstract.

Foxe JJ, et al. Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task. Neuropharmacology. ;62(7):-. View abstract.

Furushima D, Sugiyama I, Nomura Y, Unno K, Yamada H. Effect of Combined Ingestion of L-Theanine and L-Arginine for Short-Term Psychological Stress in Young Adults: A Randomized Placebo-Controlled Study. J Nutr Sci Vitaminol (Tokyo) ;68(6):540-546. View abstract.

Graham HN. Green tea composition, consumption, and polyphenol chemistry. Prev Med ;21:334-50. View abstract.

Hamaguchi R, Tsuchiya T, Miyata G, et al. Efficacy of oral administration of cystine and theanine in colorectal cancer patients undergoing capecitabine-based adjuvant chemotherapy after surgery: a multi-institutional, randomized, double-blinded, placebo-controlled, phase II trial (JORTC-CAM03). Support Care Cancer. . View abstract.

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. ;11(10). pii: E. View abstract.

Hidese S, Ota M, Wakabayashi C, et al. Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study. Acta Neuropsychiatr ;29(2):72-9. View abstract.

Kahathuduwa CN, Dassanayake TL, Amarakoon AMT, Weerasinghe VS. effects of theanine, caffeine and theanine-caffeine combination on attention. Nutr Neurosci ;20(6):369-77. View abstract.

Kahathuduwa CN, Wakefield S, West BD, 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 ;10(1):. View abstract.

Kakuda T, Nozawa A, Unno T, et al. Inhibiting effects of theanine on caffeine stimulation evaluated by EEG in the rat. Biosci Biotechnol Biochem ;64:287-93. View abstract.

Kakuda T, Yanase H, Utsunomiya K, et al. Protective effect of gamma-glutamylethylamide (theanine) on ischemic delayed neuronal death in gerbils. Neurosci Lett ;289:189-92. View abstract.

Kardashev A, Ratner Y, Ritsner MS.Add-on pregnenolone with L-theanine to antipsychotic therapy relieves negative and anxiety symptoms of schizophrenia: an 8-week, randomized, double-blind, placebo-controlled trial. Clin Schizophr Relat Psychoses. ;12(1):31-41. doi: 10./CSRP.KARA.. View abstract.

Kawada S, Kobayashi K, Ohtani M, Fukusaki C. Cystine and theanine supplementation restores high-intensity resistance exercise-induced attenuation of natural killer cell activity in well-trained men. J Strength Cond Res ;24(3):846-51. View abstract.

Kelly SP, Gomez-Ramirez M, Montesi JL, Foxe JJ. L-theanine and caffeine in combination affect human cognition as evidenced by oscillatory alpha-band activity and attention task performance. J Nutr ;138(8):S-S. View abstract.

Kimura R, Murata T. Effect of theanine on norepinephrine and serotonin levels in rat brain. Chem Pharm Bull ;34:-57.

Küçükibrahimoglu E, Saygin MZ, Caliskan M, Kaplan OK, Unsal C, Gören MZ. The change in plasma GABA, glutamine and glutamate levels in fluoxetine- or S-citalopram-treated female patients with major depression. Eur J Clin Pharmacol. Jun;65(6):571-7. doi: 10./s-009--7. View abstract.

Langan-Evans C, Hearris MA, Gallagher C, et al. Nutritional Modulation of Sleep Latency, Duration, and Efficiency: A Randomized, Repeated-Measures, Double-Blind Deception Study. Med Sci Sports Exerc ;55(2):289-300. View abstract.

Lin L, Zeng L, Liu A, et al. L-theanine regulates glucose, lipid, and protein metabolism via insulin and AMP-activated protein kinase signaling pathways. Food Funct. ;11(2):-. View abstract.

Lu K, Gray MA, Oliver C, et al. The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans. Hum Psychopharmacol ;19:457-65. View abstract.

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. ;16(4):348-354. View abstract.

Maloh J, Chakkalakal M, Sulaiman F, Burney W, Chambers CJ, Sivamani RK. Combining Topical and Oral Botanicals for Skin Redness, Pigmentation, Sleep, and Mood: A Randomized Controlled Study. J Clin Med ;11(22):. View abstract.

Miodownik C, Maayan R, Ratner Y, et al. 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. Clin Neuropharmacol ;34(4):155-60. View abstract.

Miyachi T, et al. Perioperative oral administration of cystine and theanine enhances recovery after distal gastrectomy: a prospective randomized trial. JPEN. ;37(3):384-391. View abstract.

Murakami S, Kurihara S, Koikawa N, et al. Effects of oral supplementation with cystine and theanine on the immune function of athletes in endurance exercise: randomized, double-blind, placebo-controlled trial. Biosci Biotechnol Biochem ;73(4):817-21. View abstract.

Nematizadeh M, Ghorbanzadeh H, Moghaddam HS, et al. L-theanine combination therapy with fluvoxamine in moderate-to-severe obsessive-compulsive disorder: A placebo-controlled, double-blind, randomized trial. Psychiatry Clin Neurosci ;77(9):478-485. View abstract.

Noah L, Morel V, Bertin C, et al. Effect of a Combination of Magnesium, B Vitamins, Rhodiola, and Green Tea (L-Theanine) on Chronically Stressed Healthy Individuals-A Randomized, Placebo-Controlled Study. Nutrients. Apr 29;14(9):. View abstract.

Okamoto H, Taniyama Y, Sakurai T, et al. Perioperative Administration of Cystine and Theanine Suppresses Inflammation and Facilitates Early Rehabilitation and Recovery after Esophagectomy: A Randomized, Double-Blind, Controlled Clinical Trial. Nutrients ;14(11):. View abstract.

Owen GN, Parnell H, De Bruin EA, Rycroft JA. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci ;11(4):193-8. View abstract.

Park SK, Jung IC, Lee WK, 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 ;14(4):334-43. View abstract.

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 ;72(1):34-42. View abstract.

Rizzo R, Prato A, Scerbo M, Saia F, Barone R, Curatolo P. Use of Nutritional Supplements Based on L-Theanine and Vitamin B6 in Children with Tourette Syndrome, with Anxiety Disorders: A Pilot Study. Nutrients ;14(4):852. View abstract.

Sadzuka Y, Sugiyama T, Miyagishima A, et al. The effects of theanine, as a novel biochemical modulator, on the antitumor activity of adriamycin. Cancer Lett ;105:203-9. View abstract.

Sadzuka Y, Sugiyama T, Sonobe T. Efficacies of tea components on doxorubicin induced antitumor activity and reversal of multidrug resistance. Toxicol Lett ;114:155-62. View abstract.

Sadzuka Y, Sugiyama T, Sonobe T. Improvement of idarubicin induced antitumor activity and bone marrow suppression by theanine, a component of tea. Cancer Lett ;158:119-24. View abstract.

Sakato Y. The chemical constituents of tea: III. A new amide theanine. Nippon Nogei Kagakukaishi ;23:262-267.

Sarris J, Byrne GJ, Cribb L, et al. L-theanine in the adjunctive treatment of generalized anxiety disorder: a double-blind, randomized, placebo-controlled trial. J Psych Res ;110:31-7. View abstract.

Scheid L, et al. Kinetics of L-theanine uptake and metabolism in healthy participants are comparable after ingestion of L-theanin via capsules and green tea. J Nutr. ;142(12):-. View abstract.

Shamabadi A, Fattollahzadeh-Noor S, Fallahpour B, A Basti F, Khodaei Ardakani MR, Akhondzadeh S. L-Theanine adjunct to risperidone in the treatment of chronic schizophrenia inpatients: a randomized, double-blind, placebo-controlled clinical trial. Psychopharmacology (Berl) . View abstract.

Shamabadi A, Kafi F, Arab Bafrani M, Asadigandomani H, A Basti F, Akhondzadeh S. l-theanine adjunct to sertraline for major depressive disorder: A randomized, double-blind, placebo-controlled clinical trial. J Affect Disord ;333:38-43. View abstract.

Sugiyama T, Sadzuda Y. Enhancing effects of green tea components on the antitumor activity of adriamycin against M ovarian sarcoma. Cancer Lett ;133:19-26. View abstract.

Sugiyama T, Sadzuka Y, Tanaka K, Sonobe T. Inhibition of glutamate transporter by theanine enhances the therapeutic efficacy of doxorubicin. Toxicol Lett :121:89-96. View abstract.

Sugiyama T, Sadzuka Y. Combination of theanine with doxorobucin inhibits hepatic metastasis of M ovarian sarcoma. Clin Cancer Res ;5:413-6. View abstract.

Thiagarajah K, Chee HP, Sit NW. Effect of Alpha-S1-Casein Tryptic Hydrolysate and L-Theanine on Poor Sleep Quality: A Double Blind, Randomized Placebo-Controlled Crossover Trial. Nutrients ;14(3):652. View abstract.

Tsuchiya T, Honda H, Oikawa M, et al. Oral administration of the amino acids cystine and theanine attenuates the adverse events of S-1 adjuvant chemotherapy in gastrointestinal cancer patients. Int J Clin Oncol ;21(6):-90. View abstract.

Unno K, et al. Anti-stress effect of theanine on students during pharmacy practice: positive correlation among salivary a-amylase activity, trait anxiety and subjective stress. Pharmacol Biochem Behav. ;111:128-135. View abstract.

Williams J, Kellett J, Roach PD, et al. L-theanine as a functional food additive: its role in disease prevention and health promotion. Beverages ;2(2):13.

Williams J, McKune AJ, Georgousopoulou EN, et al. The effect of L-theanine incorporated in a functional food product (mango sorbet) on physiological responses in healthy males: a pilot randomised controlled trial. Foods ;9(3):371. View abstract.

Yokogoshi H, Kobayashi M. Hypotensive effect of gamma-glutamylethylamide in spontaneously hypertensive rats. Life Sci ;62:-8. View abstract.

Yokogoshi H, Mochizuki M, Saitoh K. Theanine-induced reduction of brain serotonin concentration in rats. Biosci Biotechnol Biochem ;62:816-7. View abstract.

Yokozawa T, Dong E. Influence of green tea and its three major components upon low-density lipoprotein oxidation. Exp Toxicol Pathol ;49:329-35. View abstract.

Yokozawa T, Oura H, Nakagawa H, et al. Effects of a component of green tea on the proliferation of vascular smooth muscle cells. Biosci Biotechnol Biochem ;59:-6. View abstract.

Yoto A, Motoki M, Murao S, Yokogoshi H. Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses. J Physiol Anthropol. ;31:28. View abstract.

Zheng G, Sayama K, Okubo T, et al. Anti-obesity effects of three major components of green tea, catechins, caffeine and theanine, in mice. In Vivo ;18:55-62. View abstract.

L-theanine is a non-protein amino acid found in tea plants (Camellia sinensis L.) from which green and black tea are made. It's the main source of flavor in tea and has a caramel-like taste that reduces the bitter flavor of other compounds found in tea leaves.

In addition to being found in tea products, L-theanine can also be taken as a dietary supplement.

L-theanine is best known for its stress-relieving and anti-anxiety effects, but it may benefits health in several other ways, too. There are a few ways to take L-theanine to ensure safety and minimize any side effects.

Benefits of L-Theanine 

L-theanine has antioxidant and anti-inflammatory properties as well as regulatory effects on anxiety and the immune system. Due to these properties, research suggests supplementing with L-theanine may benefit health in several ways.

Helps Reduce Stress and Anxiety

L-theanine has the ability to act on the central nervous system, influencing certain pathways and receptors in the brain to reduce symptoms of stress and anxiety.

L-theanine is able to cross the blood-brain barrier&#;a layer of cells between the brain's blood vessels and the brain tissue that prevents harmful substances from reaching the brain.

This means L-theanine can reach the brain to modulate neurotransmitters, which are molecules that send signals to different cells in the body. Specifically, L-theanine reduces the release of glutamate, an excitatory neurotransmitter that promotes these signals. During times of anxiety and stress, these signals can become hyperactive, so reducing glutamate may help regulate anxiety.

Contact us to discuss your requirements of L-Theanine for Cognitive. Our experienced sales team can help you identify the options that best suit your needs.

L-theanine also increases the release of γ-aminobutyric acid (GABA), and inhibitory neurotransmitter that blocks these signals. GABA is thought to help regulate anxiety, especially in people with anxiety disorders.

L-theanine also enhances the release of the anxiety-mediating compound dopamine and increases alpha-frequency brain waves, which is a pattern of brain activity associated with relaxation.

A review that included nine studies found supplementation with doses of L-theanine ranging from 200 to 400 milligrams (mg) per day may help reduce stress and anxiety in people exposed to stressful situations.

Other research shows supplementing with L-theanine in doses ranging from 200 to 400 mg per day for four to eight weeks may help improve symptoms of anxiety with minimal side effects.

Supports Restful Sleep

Due to its relaxing effects on the nervous system, L-theanine may help improve sleep quality. 

A small study of 30 adults found participants who took 200 mg of L-theanine per day for four weeks experienced reductions in sleep latency&#;the time it takes to fall asleep. They also saw reductions in sleep disturbance and use of sleep medication compared to participants who took a placebo treatment.

A study of 160 people tested the efficacy of various supplements, including L-theanine, for their sleep benefits. Researchers found supplementing with 200 mg of L-theanine for seven days significantly improved sleep problems such as trouble falling and staying asleep.

Could Boost Cognitive Function

L-theanine directly impacts brain function, and study findings suggest L-theanine supplements may benefit memory and attention by improving the brain&#;s ability to focus and remember information. 

A study including 69 Japanese adults between the ages of 50 and 69 showed a single dose of 100.6 mg of  L-theanine improved reaction time and working memory on cognitive tests.

Additionally, a study of 32 healthy young adults found doses of L-theanine ranging from 100 to 400 mg significantly improved attention and information processing compared to baseline.

L-theanine also has neuroprotective properties, meaning it may protect brain cells from age-related damage and reduce the risk of cognitive conditions such as Parkinson's Disease. Green tea&#;s high content of L-theanine is thought to be a major reason why people who drink green tea regularly are at a lower risk of developing dementia.

May Improve Depressive Symptoms

L-theanine may help reduce depressive symptoms by modulating the activity of neurotransmitters, like dopamine. 

A small study of 20 people with major depressive disorder (MDD) found supplementation with 250 mg of L-theanine for eight weeks significantly reduced symptoms of depression and anxiety. It also improved certain aspects of cognitive health, such as verbal memory and response time, compared to baseline.

Research also shows L-theanine may have a positive effect on symptoms related to mental health disorders such as schizophrenia and schizoaffective disorder.

While these findings are encouraging, it&#;s important to discuss supplement use with your healthcare provider before using L-theanine for mental health disorders like depression.

How to Take L-Theanine 

L-theanine is available in several forms, including pills, liquids, capsules, and powders. You can also get some L-theanine by drinking certain green or black teas.

L-theanine can be taken on its own or in combination with other calming substances. For example, L-theanine is commonly combined with magnesium, a mineral thought to help regulate stress.

L-theanine can be taken at any time of day, including in the morning to help support healthy stress response and at night before bed to promote restful sleep.

Dosage 

Dosing of L-theanine varies, but most studies have used doses ranging from 100 to 400 mg per day. Higher doses of L-theanine have been safely used without adverse side effects.

The amount of L-theanine found in teas may vary depending on when and where the tea is sourced and how the tea is brewed. Green, black, white, and oolong teas typically contain about 5-7 mg of L-theanine per gram of tea.

Is L-Theanine Safe?

L-theanine has been shown to be safe, even when taken in high doses. It&#;s generally well-tolerated and is not associated with health risks or side effects.

However, L-theanine may not be safe for people who are pregnant or breastfeeding, or people who have low blood pressure. L-theanine may lower blood pressure levels, so it could cause blood pressure to drop too low.

Drinking high amounts of L-theanine-containing teas that are caffeinated could cause side effects like headaches, dizziness, and a racing heart beat. Most people can safely consume about 400 mg of caffeine per day.

Potential Drug Interactions

There is some evidence L-theanine supplements may lower blood pressure. If you take one or more medications to lower blood pressure, you may want to avoid taking L-theanine.

Due to its relaxing and sleep-supporting effects, L-theanine may also have an additive effect with some sedative medications.

Avoid taking supplements containing D-theanine as it may prevent the absorption of L-theanine in the body.

Talk to your healthcare provider before starting a new supplement, especially if you take one or more medications.

What to Look For

When shopping for an L-theanine supplement, it&#;s important to choose high-quality products from trusted supplement brands. 

Whenever possible, purchase L-theanine supplements that have been third-party tested by organizations like ConsumerLab and NSF International, which set strict standards for supplement quality and safety.

It&#;s also important to choose supplements you can easily tolerate. If you have difficulty swallowing pills, you may want to purchase a liquid or powder L-theanine supplement. 

Can You Take Too Much L-Theanine

L-theanine isn&#;t known to be toxic and hasn&#;t been shown to have any adverse effects on health, even when taken in high doses.

However, it's best to follow the dosing instructions listed on the supplement product.

If you are drinking teas for L-theanine, drinking more than 400 mg of caffeine per day may cause side effects. One eight-ounce cup of tea may contain 14-60 mg of caffeine.

Side Effects of L-Theanine

L-theanine supplements haven&#;t been associated with any side effects. 

However, drinking large amounts of L-theanine-containing caffeinated tea could lead to symptoms like headaches, dizziness, and a racing heart. Too much caffeine may also lead to anxiety and trouble sleeping.

A Quick Review

L-theanine is an amino acid that is concentrated in tea and can also be taken as a dietary supplement. It has calming effects on the body and may help reduce stress and relieve symptoms of anxiety and depression.

L-theanine supplements may also help promote restful sleep and improve certain aspects of cognitive function, like attention and memory.

Supplements of L-theanine are considered safe and aren&#;t associated with any side effects. However, it&#;s important to talk to your healthcare provider before starting a new supplement to ensure it's safe and appropriate for your specific health needs.

For more information, please visit L-Theanine for Nootropic.