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  • The top ingredients for cognition, focus and mood - Nutra USA, 7/14/17 - "omega-3 ... Phosphatidylserine (PS) ... B-vitamins ... Vitamin E ... Lutein ... Citicoline ... Magnesium ... L-theanine ... Curcumin ... Resveratrol ... Blueberry anthocyanins ... Inositol-stabilized arginine silicate ... Spearmint extract ... Ashwaganda ... Bacopa ... Teacrine"
  • L-theanine may boost attention for anxious folks: Study - Nutra USA, 5/11/11 - "L-theanine, an amino acid found in tea leaves, is thought to help reduce stress, promote relaxation and improve the quality of sleep. L-theanine is found in tea leaves in low concentrations (less than 2 percent), which means that effective dosage levels (of 100 – 200mg/day) cannot be delivered from drinking tea ... Student with high anxiety were put in one group, while students with minimal anxiety were put in another group. Both groups received water or water plus 200 mg of L-theanine per 100 ml of water. The test was performed repeatedly and assessments performed between 15 and 60 minutes after ingestion ... Results showed that highly anxious students receiving the L-theanine displayed a slowing of their heart rate, improved attentional performance, and better reaction times, compared to members of the same group receiving placebo ... It is noteworthy to mention that unlike other conventional anti-anxiety treatments, L-theanine did not result in increased drowsiness, slowed reflexes, or impaired concentration ... Results of a present study showed that ingestion of 200 mg of L-theanine changes the electrical activity in the brain by increasing alpha electric band measured by EEG" - See theanine at Amazon.com.
  • Tea compounds may boost attention span: Unilever - Nutra USA, 1/19/10 - "This study provided further evidence that the L-theanine/caffeine combination improves attention on the switch task ... The improvement in accuracy in combination with unaltered response speed is in line with previous studies ... Tentative evidence was [also] found that the effect of the L-theanine/caffeine combination on attention is not specific to the visual modality, as we found faster responses in both the visual and auditory modality on the intersensory task after the combination as compared to placebo ... Taken together with the previous studies, we conclude that a high dose of L-theanine combined with caffeine, at the level of a single cup of tea, can help to improve attention" - [Abstract]
  • L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness - Appetite. 2010 Jan 13 - "The results support previous evidence that L-theanine and caffeine in combination can improve attention"
  • Green, Black Tea Can Reduce Stroke Risk, Research Suggests - Science Daily, 3/4/09 - "By drinking three cups of tea a day, the risk of a stroke was reduced by 21 percent. It didn't matter if it was green or black tea ... the effect appears to be linear ... researchers have speculated that the antioxidant epigallocatechin gallate (EGCG) or the amino acid theanine may be what helps. Antioxidants are believed to help prevent coronary artery disease ... we do know that theanine is nearly 100-percent absorbed .... It gets across the blood-brain barrier and it looks a lot like a molecule that's very similar to glutamate, and glutamate release is associated with stroke" - See green tea extract at Amazon.com and theanine at Amazon.com.
  • L-Theanine: the Next Supplement Superstar - Dr. Murray's Natural Living, 9/20/06
  • Are You Easily Distracted? Try Some Tea - US News and World Report, 10/8/07 - "the amino acid theanine, which is found in green, black, and oolong teas, causes a decrease in the brain's "alpha rhythms" when people perform complex attention tasks, causing them to pay closer attention. His ongoing research, funded by the food and beverage conglomerate Unilever, suggests that theanine and caffeine together improve performance more than either substance alone ... in mice, at least—tea's main antioxidant shows an ability to curb brain cell death and encourage neurons to repair themselves"
  • Theanine - Natural Support for Sleep, Mood, and Weight - Life Extension Magazine, 1/06 - "Preliminary studies show that blocking certain signals in the brain activated by glutamate may be as effective as prescription antidepressants.36,37 L-theanine may act as a glutamate antagonist.38 Researchers believe that glutamate receptor antagonists may offset the harmful effects of high glucocorticoid levels and offer neuroprotective effects against both acute and chronic neurodegenerative diseases"
  • Natural remedies ease anxiety - Natural Food Merchandiser, 10/05 - "Relora ... L-theanine ... Phosphatidylserine"
  • Wrong form of theanine interferes with absorption - Nutra USA, 5/10/05
  • Sleep easy with green tea - Nutra USA, 3/16/04 - "200mg of L-theanine or a placebo ... all subjects reported a significant absence of feeling exhausted and a reduced need for sleep when administered with the L-theanine, compared to the placebo"
  • An Anti-Anxiety Agent in Tea? - Dr. Weil, 3/11/04
  • Health Benefit of Tea: Add Immune Boost That Helps Fight Germs - WebMD, 4/21/03
  • Stress, Cortisol and Health - Supplement Watch Newsletter, 10/02 - "several lines of evidence have converged to solidify the concept that stress makes us fat (because of cortisol), thins our bones (because of cortisol), shrinks our brains (because of cortisol), suppresses our immune system (because of cortisol), saps our energy levels (because of cortisol), and kills our sex drive (because of cortisol) ... Take a daily multivitamin/multi-mineral supplement - because calcium, magnesium, vitamin C and B-complex vitamins are needed for a proper stress response ... Chief among the supplements with documented cortisol-controlling effects are Phosphatidylserine, Beta-sitosterol, Magnolia bark, Theanine, Epimedium, Ashwagandha and Passionflower"
  • Theanine Enhances Chemotherapy And Reduces Side Effects - Life Extension Magazine, 7/02
  • The Ultimate Relaxant - Life Extension Magazine, 1/02 - "Theanine is an amino acid found in green tea. It helps to produce a calming effect in the brain and induces a feeling of relaxation and well-being. Best of all, it does all of this without causing drowsiness. In fact, studies have shown that theanine enhances the ability to learn and remember. One of the other benefits of this amino acid is that it helps to lower blood pressure naturally, by enhancing GABA in the brain"
  • A New Natural Relaxant - Life Extension Magazine, 10/01 - "Theanine readily crosses the blood-brain barrier of humans and exerts subtle changes in biochemistry. An increase in alpha waves has been documented, and the effect has been compared to getting a massage or taking a hot bath. Theanine is different than kava-kava in that it doesn’t cause drowsiness. And unlike tranquilizing drugs, it doesn’t interfere with the ability to think ... Theanine increases GABA, while caffeine decreases it. GABA doesn’t just relax, it also creates a sense of well-being. Theanine’s ability to increase this brain chemical can put you in a better mood by changing biochemistry. Theanine also increases levels of dopamine, another brain chemical with mood-enhancing effects"
  • Shelf Stockers for 2001 - Nutrition Science News, 1/01 - "The mechanism involved appears to be the way theanine affects the metabolism or the release of the neurotransmitters dopamine and serotonin"
  • Nutraceutical of the Year - Nutrition Science News, 9/00


  • Dose-response effect of L-theanine on psychomotor speed, sustained attention, and inhibitory control: a double-blind, placebo-controlled, crossover study - Nutr Neurosci 2022 Oct 20 - "L-theanine is a non-protein-forming amino acid found in tea. Previous research shows high doses (100-400 mg) of L-theanine enhances attention, mainly by reducing mind wandering and distracter processing. We hypothesized that these indirect mechanisms could significantly improve the performance of low-level attentional tasks, whereas the relative contribution could be less in complex attentional tasks that require active, higher-order processing of target stimuli ... conducted a double-blind, placebo-controlled, counterbalanced, four-way crossover study in 32 healthy young adults, where we compared the effects of three doses of L-theanine (100, 200 and 400 mg) with a placebo (distilled water), administered before and 50 min after dosing, on three attentional tasks from the Cambridge Neuropsychological Test Automated Battery [viz. Reaction Time (RTI)-visuomotor speed, Rapid Visual Information Processing (RVP)-sustained attention, and Stop Signal Task (SST)-inhibitory control]. Results were analyzed in dose × time repeated measures ANOVA models, with subsequent pairwise comparisons ... Active doses significantly improved reaction times in the RTI (100-200 mg) and RVP (200-400 mg) tasks from baseline (p < 0.05), but once controlled for the change-from-baseline caused by placebo, only the RTI simple reaction times showed significant improvements, following 100 mg (Δ = 16.3 ms, p = 0.009) and 200 mg (Δ = 16.9 ms, p = 0.009) of L-theanine" - See L-theanine at Amazon.com.
  • Protective Effect of l-Theanine against DSS-Induced Colitis by Regulating the Lipid Metabolism and Reducing Inflammation via the NF-κB Signaling Pathway - J Agric Food Chem 2021 Nov 16 - "In summary, l-theanine plays a protective role in DSS-induced colitis via downregulating the NF-κB signaling pathway and regulating lipid metabolism disorders"
  • Effects of l-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study - Journal of Medicinal FoodVol. 24, No. 4 - "The single dose of l-theanine reduced the reaction time to attention tasks (Stroop test, Part 1), and it increased the number of correct answers and decreased the number of omission errors in working memory tasks (4-Part continuous performance test, Part 4). In conclusion, our study indicated that l-theanine may contribute to improving attention, thus enhancing working memory and executive functions" - [Nutra USA]
  • Theanine and cancer: A systematic review of the literature - Phytother Res 2021 Apr 23 - "A growing literature indicates several health benefits of theanine, a major nonprotein derivative amino acid special to tea, and a nonedible mushroom ... Most of the included in vitro and ex vivo studies reported beneficial effects of theanine on the proliferation, apoptosis, metastasis, migration, and invasion in various cancer cell lines. The in vivo studies also supported the potential impacts of theanine on cancer incidence or progression. Theanine exerted its anticancer function by inhibiting EGFR, VEGFR, Met, and Akt/mTOR, JAK2/STAT3, and ERK/NFκB pathways, as well as activating the intrinsic apoptosis pathway and caspase-independent programmed cell death. In conclusion, the results indicated moderate apoptotic, antimetastatic, antimigration, and anti-invasion effects, along with the mild antiproliferative influence of theanine on cancer"
  • L-theanine improves neurophysiological measures of attention in a dose-dependent manner: a double-blind, placebo-controlled, crossover study - Nutr Neurosci 2020 Aug 11;1-11 - "L-theanine, a non-proteinic amino acid found in tea, is known to enhance attention particularly in high doses, with no reported adverse effects ... The findings indicate L-theanine can increase attentional processing of auditory information in a dose-dependent manner"
  • Theanine, the Main Amino Acid in Tea, Prevents Stress-Induced Brain Atrophy by Modifying Early Stress Responses - Nutrients. 2020 Jan 8;12(1) - "Npas4 and Lcn2 are involved in the brain atrophy and stress vulnerability of SAMP10 mice, which are prevented by the consumption of theanine, causing changes in the expression of these genes"
  • L-Theanine Improves Immunity by Altering TH2/TH1 Cytokine Balance, Brain Neurotransmitters, and Expression of Phospholipase C in Rat Hearts - Med Sci Monit. 2016 Feb 28;22:662-669 - "Administration of 400 mg/kg BWL-theanine improved immune function of the rats by increasing the splenic weight, altering the Th2/Th1 cytokine balance, decreasing the corticosterone level in the serum, elevating dopamine and 5-hydroxytryptamine in the brain, and regulating the mRNA expression of PLC isomers in the heart" - See theanine at Amazon.com.
  • Acute effects of theanine, caffeine and theanine-caffeine combination on attention - Nutr Neurosci. 2016 Feb 11 - "In a placebo-controlled, five-way crossover trial in 20 healthy male volunteers, we compared the effects of l-theanine (200 mg), caffeine (160 mg), their combination, black tea (one cup) and a placebo (distilled water) on cognitive (simple [SVRT] and recognition visual reaction time [RVRT]) and neurophysiological (event-related potentials [ERPs]) measures of attention ... Mean RVRT was significantly improved by theanine (P = 0.019), caffeine (P = 0.043), and theanine-caffeine combination (P = 0.001), but not by tea (P = 0.429) or placebo ... A dose of theanine equivalent of eight cups of back tea improves cognitive and neurophysiological measures of selective attention, to a degree that is comparable with that of caffeine. Theanine and caffeine seem to have additive effects on attention in high doses"
  • Advantageous effect of theanine intake on cognition - Nutr Neurosci. 2014 Feb 7 - "Theanine, γ-glutamylethylamide, is one of the major amino acid components in green tea. On the basis of the preventive effect of theanine intake after weaning on stress-induced impairment of recognition memory, the advantageous effect of theanine intake on recognition memory was examined in young rats, which were fed water containing 0.3% theanine for 3 weeks after weaning ... The levels of brain-derived neurotropic factor and nerve growth factor in the hippocampus were significantly higher in theanine-administered rats than in the control rats. The present study indicates the advantageous effect of theanine intake after weaning on recognition memory. It is likely that theanine intake is of advantage to the development of hippocampal function after weaning" - See theanine at Amazon.com.
  • Green tea extract shows memory boosting activity: Study - Nutra USA, 5/4/11 - "A combination of a green tea extract with L-theanine was associated with improvements in immediate and delayed recall, and general memory, according to findings published in the Journal of Medicinal Foods ... As a natural ingredient with a long history of consumption, LGNC-07 [ – a combination of green tea extract and L-theanine - ] should be considered as a potential nutraceutical candidate for enhancing cognitive performance" - [Abstract]
  • Antidepressant-like Effects of L-theanine in the Forced Swim and Tail Suspension Tests in Mice - Phytother Res. 2011 Mar 21 - "L-theanine (γ-glutamylethylamide), an amino acid component of green tea, has been shown to reduce mental and physical stress, and to improve memory function. In this study, the antidepressant effect of L-theanine was investigated in mice using the forced swim test, tail suspension test, open-field test and reserpine test. L-theanine produced an antidepressant-like effect, since the administration of L-theanine at doses of 1, 4 and 20 mg/kg for 10 successive days significantly reduced the immobility time in both the forced swim test and tail suspension test, compared with the control group, without accompanying changes in ambulation in the open-field test. Moreover, L-theanine significantly antagonized reserpine-induced ptosis and hypothermia. Taken together, these results indicate that L-theanine possessed an antidepressant-like effect in mice, which may be mediated by the central monoaminergic neurotransmitter system"
  • Neuroprotective effects of the green tea components theanine and catechins - Biol Pharm Bull 2002 Dec;25(12):1513-8