Supplement
Theanine is an amino acid found mainly in tea that appears to raise alpha brain waves and influence calming messengers like GABA and serotonin, promoting relaxed alertness without sedation. Most people look at it for stress, and the evidence is moderate: in small trials, anxiety symptoms improved. Those findings rest on two studies with only 51 people in total, and research on alertness found no clear difference, so the picture is still preliminary.
Sources: PMID 31758301; PMID 16930802
- Updated
- How we grade
- 36 studies cited
- Best evidence
- Grade B
- Conditions studied
- 16
- Outcomes
- 155
- Graded outcomes
- 01105
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 2 studies | 51 people | ||
| Attention | Improves (the measure goes up) | 4 studies | 30 people | |||
Studies that measured attention
| ||||||
| Executive Function | Improves (the measure goes up) | 3 studies | 30 people | |||
Studies that measured executive function
| ||||||
| Sleep Quality | Improves (the measure goes up) | 2 studies | 30 people | |||
Studies that measured sleep quality | ||||||
| Cortisol | Improves (the measure goes down) | 1 study | 30 people | |||
| Heart Rate | Improves (the measure goes down) | 1 study | 12 people | |||
| Salivary Alpha-Amylase | Improves (the measure goes up) | 1 study | 20 people | |||
| Stress Signs and Symptoms | Improves (the measure goes down) | 1 study | 71 people | |||
| Cognition | Improves (the measure goes up) | 30 people | ||||
| Depression Symptoms | Improves (the measure goes down) | 30 people | ||||
| Mood | Improves (the measure goes up) | 30 people | ||||
| Motor Speed | Improves (the measure goes up) | 30 people | ||||
| Sleep Disturbance Signs and Symptoms | Improves (the measure goes down) | 30 people | ||||
| Sleep Duration | Improves (the measure goes up) | 30 people | ||||
| Sleep Latency | Improves (the measure goes down) | 30 people | ||||
| Verbal Fluency | Improves (the measure goes up) | 30 people | ||||
| Verbal Memory | Improves (the measure goes up) | 30 people | ||||
| Working Memory | Improves (the measure goes up) | 30 people | ||||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 2 studies | 46 people | ||
| Alertness No effect | NoneNo effect | 86 people | ||||
| Reaction Time | Improves (the measure goes up) | 5 studies | 144 people | |||
Studies that measured reaction time
| ||||||
| Attention | Improves (the measure goes up) | 4 studies | 216 people | |||
Studies that measured attention
| ||||||
| Executive Function | Improves (the measure goes up) | 3 studies | 120 people | |||
Studies that measured executive function
| ||||||
| Sleep Quality | Improves (the measure goes up) | 2 studies | 30 people | |||
| Subjective Well-Being | Improves (the measure goes up) | 2 studies | 62 people | |||
| Cortisol | Improves (the measure goes down) | 1 study | 38 people | |||
| Prepulse Inhibition | Improves (the measure goes up) | 1 study | 14 people | |||
| Blood Pressure | Improves (the measure goes down) | 72 people | ||||
| Depression Symptoms | Improves (the measure goes down) | 30 people | ||||
| Fatigue Symptoms | Improves (the measure goes down) | 24 people | ||||
| Headaches | Improves (the measure goes down) | 24 people | ||||
| Motor Speed | Improves (the measure goes up) | 30 people | ||||
| Numerical Memory | Improves (the measure goes up) | 24 people | ||||
| Processing Accuracy | Improves (the measure goes up) | 53 people | ||||
| Processing Speed | Improves (the measure goes up) | 24 people | ||||
| Sedation | Improves (the measure goes up) | 16 people | ||||
| Sleep Disturbance Signs and Symptoms | Improves (the measure goes down) | 30 people | ||||
| Sleep Latency | Improves (the measure goes down) | 30 people | ||||
| Verbal Fluency | Improves (the measure goes up) | 30 people | ||||
| Verbal Memory | Improves (the measure goes up) | 30 people | ||||
| Working Memory | Improves (the measure goes up) | 106 people | ||||
Focus & Attention
- Anxiety Symptoms: improves
- Reaction Time: improves
- Attention: improves
Sleep Health
- Anxiety Symptoms: improves
- Attention: improves
- Executive Function: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 2 studies | 30 people | ||
| Attention | Improves (the measure goes up) | 4 studies | 30 people | |||
Studies that measured attention
| ||||||
| Executive Function | Improves (the measure goes up) | 3 studies | 30 people | |||
Studies that measured executive function
| ||||||
| Sleep Quality | Improves (the measure goes up) | 2 studies | 900 people | |||
Studies that measured sleep quality | ||||||
| Insomnia Signs and Symptoms | Improves (the measure goes down) | 1 study | 40 people | |||
Studies that measured insomnia signs and symptoms | ||||||
| Day-Time Dysfunction | Improves (the measure goes up) | 571 people | ||||
| Depression Symptoms | Improves (the measure goes down) | 30 people | ||||
| Motor Speed | Improves (the measure goes up) | 30 people | ||||
| Sleep Disturbance Signs and Symptoms | Improves (the measure goes down) | 30 people | ||||
| Sleep Latency | Improves (the measure goes down) | 877 people | ||||
| Verbal Fluency | Improves (the measure goes up) | 30 people | ||||
| Verbal Memory | Improves (the measure goes up) | 30 people | ||||
| Working Memory | Improves (the measure goes up) | 30 people | ||||
General Cardiovascular Health
- Anxiety Symptoms: improves
- Reaction Time: improves
- Heart Rate: improves
Immune Health
- Anxiety Symptoms: improves
- Heart Rate: improves
- Interleukin 4: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 2 studies | 12 people | ||
| Heart Rate | Improves (the measure goes down) | 1 study | 12 people | |||
| Interleukin 4 | Improves (the measure goes up) | 1 study | 20 people | |||
Studies that measured interleukin 4 | ||||||
| Stress Signs and Symptoms | Improves (the measure goes down) | 1 study | 12 people | |||
Studies that measured stress signs and symptoms | ||||||
| Granulocyte Count | Improves (the measure goes up) | 20 people | ||||
| Interferon Gamma | Improves (the measure goes up) | 20 people | ||||
| Interleukin 10 | Improves (the measure goes up) | 20 people | ||||
| Interleukin 2 | Improves (the measure goes up) | 20 people | ||||
| Lymphocyte Count | Improves (the measure goes up) | 20 people | ||||
| Natural Killer Cell Content | Improves (the measure goes up) | 20 people | ||||
| Total Antioxidant Capacity (TAC) | Improves (the measure goes up) | 20 people | ||||
| Treg Cells | Improves (the measure goes up) | 20 people | ||||
| White Blood Cell Count | Improves (the measure goes up) | 20 people | ||||
Schizophrenia
- Anxiety Symptoms: improves
- Subjective Well-Being: improves
- Cortisol: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 2 studies | 40 people | ||
| Subjective Well-Being | Improves (the measure goes up) | 2 studies | 40 people | |||
Studies that measured subjective well-being
| ||||||
| Cortisol | Improves (the measure goes down) | 1 study | 60 people | |||
| DHEAS | Improves (the measure goes up) | 60 people | ||||
| Insulin | Changes; see studies | 60 people | ||||
| Schizophrenia symptoms | Improves (the measure goes down) | 40 people | ||||
| Serum BDNF | Improves (the measure goes up) | 60 people | ||||
| Serum DHEA | Improves (the measure goes up) | 60 people | ||||
| Total cholesterol | Improves (the measure goes down) | 60 people | ||||
Depression
- Anxiety Symptoms: improves
- Attention: improves
- Executive Function: improves
Generalized Anxiety Disorder (GAD)
- Anxiety Symptoms: improves
- Insomnia Signs and Symptoms: improves
- Depression Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 2 studies | 46 people | ||
| Insomnia Signs and Symptoms | Improves (the measure goes down) | 1 study | 46 people | |||
Studies that measured insomnia signs and symptoms | ||||||
| Depression Symptoms | Improves (the measure goes down) | 46 people | ||||
Metabolic Health
- Anxiety Symptoms: improves
- Heart Rate: improves
- Stress Signs and Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 2 studies | 12 people | ||
| Heart Rate | Improves (the measure goes down) | 1 study | 12 people | |||
| Stress Signs and Symptoms | Improves (the measure goes down) | 1 study | 12 people | |||
Studies that measured stress signs and symptoms | ||||||
Schizoaffective Disorder
- Anxiety Symptoms: improves
- Subjective Well-Being: improves
- Schizophrenia symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 2 studies | 40 people | ||
| Subjective Well-Being | Improves (the measure goes up) | 2 studies | 40 people | |||
Studies that measured subjective well-being
| ||||||
| Schizophrenia symptoms | Improves (the measure goes down) | 40 people | ||||
Mental Resilience
- Alertness
- Executive Function: improves
- Anxiety Symptoms: improves
Mood Improvement
- Alertness
- Reaction Time: improves
- Attention: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Alertness No effect | NoneNo effect | 86 people | ||||
| Reaction Time | Improves (the measure goes up) | 5 studies | 24 people | |||
| Attention | Improves (the measure goes up) | 4 studies | 48 people | |||
| Executive Function | Improves (the measure goes up) | 3 studies | 38 people | |||
| Anxiety Symptoms | Improves (the measure goes down) | 2 studies | 14 people | |||
| Subjective Well-Being | Improves (the measure goes up) | 2 studies | 76 people | |||
| Cortisol | Improves (the measure goes down) | 1 study | 38 people | |||
| Heart Rate | Improves (the measure goes down) | 1 study | 24 people | |||
| Fatigue Symptoms | Improves (the measure goes down) | 24 people | ||||
| Headaches | Improves (the measure goes down) | 24 people | ||||
| Numerical Memory | Improves (the measure goes up) | 24 people | ||||
| Processing Accuracy | Improves (the measure goes up) | 24 people | ||||
| Processing Speed | Improves (the measure goes up) | 24 people | ||||
| Vigor/Activity | Improves (the measure goes up) | 14 people | ||||
| Working Memory | Improves (the measure goes up) | 24 people |
Aerobic Exercise Performance
- Aerobic Exercise Metrics
- Interleukin 4: improves
- Blood Lactate (Exercise): changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Aerobic Exercise Metrics No effect | NoneNo effect | 20 people | ||||
| Interleukin 4 | Improves (the measure goes up) | 1 study | 20 people | |||
| Blood Lactate (Exercise) | Changes; see studies | 20 people | ||||
| Interferon Gamma | Improves (the measure goes up) | 20 people | ||||
| Interleukin 10 | Improves (the measure goes up) | 20 people | ||||
| Interleukin 2 | Improves (the measure goes up) | 20 people | ||||
| Lymphocyte Count | Improves (the measure goes up) | 20 people | ||||
| Natural Killer Cell Content | Improves (the measure goes up) | 20 people | ||||
| Power Output | Improves (the measure goes up) | 20 people | ||||
| Total Antioxidant Capacity (TAC) | Improves (the measure goes up) | 20 people | ||||
| Treg Cells | Improves (the measure goes up) | 20 people | ||||
| White Blood Cell Count | Improves (the measure goes up) | 20 people |
General Athletic Performance
- Aerobic Exercise Metrics
- Interleukin 4: improves
- Blood Lactate (Exercise): changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Aerobic Exercise Metrics No effect | NoneNo effect | 20 people | ||||
| Interleukin 4 | Improves (the measure goes up) | 1 study | 20 people | |||
| Blood Lactate (Exercise) | Changes; see studies | 20 people | ||||
| Granulocyte Count | Improves (the measure goes up) | 20 people | ||||
| Interferon Gamma | Improves (the measure goes up) | 20 people | ||||
| Interleukin 10 | Improves (the measure goes up) | 20 people | ||||
| Interleukin 2 | Improves (the measure goes up) | 20 people | ||||
| Lymphocyte Count | Improves (the measure goes up) | 20 people | ||||
| Natural Killer Cell Content | Improves (the measure goes up) | 20 people | ||||
| Power Output | Improves (the measure goes up) | 20 people | ||||
| Total Antioxidant Capacity (TAC) | Improves (the measure goes up) | 20 people | ||||
| Treg Cells | Improves (the measure goes up) | 20 people | ||||
| White Blood Cell Count | Improves (the measure goes up) | 20 people |
Attention Deficit Hyperactivity Disorder (ADHD)
- Sleep Quality: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Sleep Quality | Improves (the measure goes up) | 2 studies | 97 people |
What the published studies found
7 automated readings
LDL cholesterol
The studies read are too weak to tell whether Theanine changes LDL cholesterol. The evidence is very weak.
3 studies counted of 8 read: 1 trial (30 people in the trials).
- Study, 2025; high-fat diet induced gestational obesity mice: improves.
LTA administration reduced weight gain, visceral/gonadal adiposity, metabolic markers (fasting glucose/insulin/cholesterol)
L-Theanine Ameliorates Metabolic Dysregulation and Adverse Fetal Outcomes in a Mice Model of Gestational Obesity: Association with FXR/FGF15 Signaling - Randomised trial, 2022; 30 people; heat-stressed Chinese Holstein dairy cows: no clear difference.
LDL-C; P = 0.053), and high-density
Alterations in nutrient digestibility and performance of heat-stressed dairy cows by dietary L-theanine supplementation - Study, 2022; HFD-induced nonalcoholic fatty liver disease mice: improves. L-theanine prevents progression of nonalcoholic hepatic steatosis by regulating hepatocyte lipid metabolic pathways via the CaMKKβ-AMPK signaling pathway
- Study, 2025; high-fat diet induced gestational obesity mice: improves.
Blood pressure
The studies read are too weak to tell whether Theanine changes blood pressure. They lean toward an improvement, which is not enough to claim one. The evidence is very weak.
3 studies counted of 7 read: 3 trials (73 people in the trials).
- Randomised trial, 2020; 11 people: no clear difference.
no differences between the three conditions (all p > 0.05)
The Effect of L-Theanine Incorporated in a Functional Food Product (Mango Sorbet) on Physiological Responses in Healthy Males: A Pilot Randomised Controlled Trial - Crossover trial, 2012; 14 people; adults undergoing physical and psychological stress: improves.
L-theanine significantly inhibited the blood-pressure increases
Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses - Crossover trial, 2008; 48 people: improves.
Theanine antagonised the effect of caffeine on blood pressure
Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together
- Randomised trial, 2020; 11 people: no clear difference.
Cardiovascular events
Too few usable studies were found to tell whether Theanine changes cardiovascular events. 9 studies were read and none could be counted.
Memory
The studies read are too weak to tell whether Theanine changes memory. They lean toward an improvement, which is not enough to claim one. The evidence is very weak.
4 studies counted of 10 read: 3 trials (27 people in the trials).
- Randomised trial, 2021; japanese men and women aged 50-69 years: improves. Effects of l-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study
- Non-randomised trial, 2017; 20 people; patients with major depressive disorder: improves.
verbal memory (p=0.005) and executive function
Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study - Randomised trial, 2011; elderly persons with normal or slight cognitive dysfunction: improves.
showed significantly lower decline in cognitive function
Neuroprotective effects of theanine and its preventive effects on cognitive dysfunction - Crossover trial, 2008; 27 people; healthy volunteers: improves.
reduced susceptibility to distracting information in the memory task
The combined effects of L-theanine and caffeine on cognitive performance and mood
Mood
The best available review (2025, 15 studies) found little or no difference in mood. 2 of the 6 studies read agree; 4 found an improvement. The evidence is moderate.
6 studies counted of 10 read: 3 reviews and 3 trials (122 people in the trials).
- Meta-analysis, 2025; 15 studies: no clear difference (the review the verdict rests on). Effects of Tea (Camellia sinensis) or its Bioactive Compounds l-Theanine or l-Theanine plus Caffeine on Cognition, Sleep, and Mood in Healthy Participants: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
- Systematic review, 2020; 9 studies; people exposed to stressful conditions: improves.
assist in the reduction of stress and anxiety
The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review - Meta-analysis, 2014; 11 studies: improves.
moderate effect sizes in favor of combined caffeine and L-theanine
Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis - Crossover trial, 2012; 14 people; humans undergoing physical and psychological stress: improves. Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses
- Randomised trial, 2011; 60 people; patients with schizophrenia or schizoaffective disorder: improves.
reduction of anxiety (P = .015; measured by the HARS scale)
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 - Randomised trial, 2008; 48 people: no clear difference. Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together
Sleep quality
The best available review (2026, 13 studies, 550 people) found an improvement in sleep quality. 4 of the 6 studies read agree; 1 found no clear difference, 1 found a worse result. The evidence is moderate.
Possible harm: 1 study read reported a worse result for sleep quality with Theanine. One abstract says: "all, except atomoxetine, affected sleep quality, such as by reducing total rapid eye movement (REM), non-REM phase, slow-wave sleep time, and longer sleep-onset latency" Check the studies below, and ask a doctor or pharmacist if this applies to you.
6 studies counted of 11 read: 4 reviews and 2 trials (30 people in the trials).
- Systematic review, 2026; 13 studies, 550 people: improves (the review the verdict rests on).
beneficial effects were reported on both objective and participant-reported outcomes
Examining the effect of L-theanine on sleep: a systematic review of dietary supplementation trials - Systematic review, 2026; healthy adults: improves.
can support sleep quality, with little effect
Effects of L-theanine on cognition, mood and sleep: evidence from human trials - Meta-analysis, 2025; 18 studies, 897 people; humans of all ages and health status: improves. The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis
- Systematic review, 2023; children with attention deficit hyperactivity disorder: worsens.
affected sleep quality, such as by reducing total rapid eye movement
Association between sleep pattern and pharmacological treatment in children with attention deficit disorder with hyperactivity: a systematic review - Crossover trial, 2023; healthy young women: no clear difference.
no difference was observed between the theanine
Theanine maintains sleep quality in healthy young women by suppressing the increase in caffeine-induced wakefulness after sleep onset - Crossover trial, 2019; 30 people; healthy adults without major psychiatric illness: improves.
Pittsburgh Sleep Quality Index (PSQI) scores decreased after L-theanine administration
Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial
- Systematic review, 2026; 13 studies, 550 people: improves (the review the verdict rests on).
Stress
The best available review (2026, 31 studies, 1,168 people) found little or no difference in stress. That review studied healthy and clinical populations. 2 of the 7 studies read agree; 5 found an improvement. The evidence is moderate.
7 studies counted of 9 read: 3 reviews and 4 trials (98 people in the trials).
- Systematic review, 2026; 31 studies, 1,168 people; healthy and clinical populations: no clear difference (the review the verdict rests on).
reduction in acute stress was modest
Cognitive and affective effects of L-Theanine: a systematic review and meta-analysis of 31 randomized trials - Systematic review, 2026; healthy adults: improves.
reduce both perceived and physiological markers of stress
Effects of L-theanine on cognition, mood and sleep: evidence from human trials - Systematic review, 2020; 9 studies; people exposed to stressful conditions: improves.
assist in the reduction of stress and anxiety
The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review - Randomised trial, 2024; 30 people; healthy adults with moderate stress: no clear difference. Safety and Efficacy of AlphaWave® L-Theanine Supplementation for 28 Days in Healthy Adults with Moderate Stress: A Randomized, Double-Blind, Placebo-Controlled Trial
- Crossover trial, 2016; 34 people; healthy adults aged 18-40: improves.
subjective stress response to a multitasking cognitive stressor, was significantly reduced
Anti-Stress, Behavioural and Magnetoencephalography Effects of an L-Theanine-Based Nutrient Drink: A Randomised, Double-Blind, Placebo-Controlled, Crossover Trial - Randomised trial, 2013; 20 people; 5th-year university students: improves.
Subjective stress was significantly lower in the theanine-group
Anti-stress effect of theanine on students during pharmacy practice: positive correlation among salivary α-amylase activity, trait anxiety and subjective stress - Crossover trial, 2012; 14 people: improves.
L-theanine reduced the Tension-Anxiety scores as compared with placebo intake.
Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses
- Systematic review, 2026; 31 studies, 1,168 people; healthy and clinical populations: no clear difference (the review the verdict rests on).
Key findings
- Anxiety SymptomsImproves (the measure goes down)
- Alertness
- Aerobic Exercise Metrics
Shop the evidence-backed picks
Third-party tested Theanine products, in the forms the graded studies used where we can match them.
- Grade B
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Studies cited
36 studies from PubMed
- Safety and Tolerability of L-Theanine Supplementation
- L-Theanine: A Unique Amino Acid with Neuroprotective Properties
- L-Theanine and Cognitive Function: A Systematic Review
- L-Theanine in Psychiatric Disorders: A Comprehensive Review
- The Effect of L-Theanine Incorporated in a Functional Food Product (Mango Sorbet) on Physiological Responses in Healthy Males: A Pilot Randomised Controlled Trial
- Effects of L-Theanine on Anxiety and Stress: A Meta-Analysis
- L-Theanine and Sleep Quality: A Review of Clinical Studies
- Caffeine and L-Theanine: Synergistic Effects on Cognition
- L-Theanine and Alpha Brain Wave Activity: A Review
- Pharmacological Effects of L-Theanine in Healthy Volunteers
- L-Theanine as a Functional Ingredient in Foods and Beverages
- The Effects of L-Theanine on Mental Performance
- Acute effects of theanine, caffeine and theanine-caffeine combination on attention
- The effects of L-theanine, caffeine and their combination on cognition and mood
- l-Theanine and caffeine improve target-specific attention to visual stimuli by decreasing mind wandering: a human functional magnetic resonance imaging study
- Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task
- Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together
- Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial
- Caffeine and theanine exert opposite effects on attention under emotional arousal
- Effects of l-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study
- L-theanine and caffeine in combination affect human cognition as evidenced by oscillatory alpha-band activity and attention task performance
- 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
- L-theanine improves neurophysiological measures of attention in a dose-dependent manner: a double-blind, placebo-controlled, crossover study.
- Effect of L-theanine on sensorimotor gating in healthy human subjects
- Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study
- L-Theanine reduces psychological and physiological stress responses
- The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review.
- Anti-stress effect of theanine on students during pharmacy practice: positive correlation among salivary α-amylase activity, trait anxiety and subjective stress
- Safety and Efficacy of AlphaWave(®) L-Theanine Supplementation for 28 Days in Healthy Adults with Moderate Stress: A Randomized, Double-Blind, Placebo-Controlled Trial.
- The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis.
- 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
- Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses
- The effect of L-theanine supplementation on the immune system of athletes exposed to strenuous physical exercise
- L-theanine in the adjunctive treatment of generalized anxiety disorder: A double-blind, randomised, placebo-controlled trial
- 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
- 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