L-TheanineEvidence & Dosage
Alpha waves, relaxation without sedation, caffeine synergy.
Evidence at a glance
- Total studies
- 342
- With abstract
- 50
- Meta / Systematic / RCT
- 64
- Highly cited
- 50
- Publication years
- 1995–2026
L-Theanine in the context of Cognition
This topic is part of our "Cognition" world. There you'll find methodology, evidence and the highest-impact levers — plus the order in which they sensibly build on each other.
Go to CognitionTop studies on L-Theanine
Ranked by influential-citation count and publication year.
The Tea Tree Genome Provides Insights into Tea Flavor and Independent Evolution of Caffeine Biosynthesis.
Mol Plant2017Study176 influential citationsTea is the world's oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich (80.9%), 3.02-Gb genome of…
Understanding different regulatory mechanisms of proteinaceous and non-proteinaceous amino acid formation in tea (Camellia sinensis) provides new insights into the safe and effective alteration of tea flavor and function.
Crit Rev Food Sci Nutr2020Review149 influential citationsAmino acids are the main contributors to tea (<i>Camellia sinensis</i>) flavor and function. Tea leaves contain not only proteinaceous amino acids but also specialized non-proteinaceous amino acids such as L-theanine and γ-aminobutyric…
L-theanine, unique amino acid of tea, and its metabolism, health effects, and safety.
Crit Rev Food Sci Nutr2017Review68 influential citationsTea has been a very popular beverage around the world for centuries. The reason that it is delicious, enabling hydration, showing warming and relaxing effect can be mentioned why it is consumed so much in addition to its prominent health…
Green tea effects on cognition, mood and human brain function: A systematic review.
Phytomedicine2017n=21systematic66 influential citationsBACKGROUND: Green tea (Camellia sinensis) is a beverage consumed for thousands of years. Numerous claims about the benefits of its consumption were stated and investigated. As green tea is experiencing a surge in popularity in Western…
L-Theanine reduces psychological and physiological stress responses.
Biol Psychol2007n=12rct63 influential citationsL-Theanine is an amino acid contained in green tea leaves which is known to block the binding of L-glutamic acid to glutamate receptors in the brain. Because the characteristics of L-Theanine suggest that it may influence psychological and…
The effects of L-theanine, caffeine and their combination on cognition and mood.
Biol Psychol2008RCT63 influential citationsL-Theanine is an amino acid found naturally in tea. Despite the common consumption of L-theanine, predominantly in combination with caffeine in the form of tea, only one study to date has examined the cognitive effects of this substance…
Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial.
Nutrients2019n=30RCT61 influential citationsThis randomized, placebo-controlled, crossover, and double-blind trial aimed to examine the possible effects of four weeks L-theanine administration on stress-related symptoms and cognitive functions in healthy adults. Participants were 30…
Transcriptomic Analysis Reveals the Molecular Mechanisms of Drought-Stress-Induced Decreases in Camellia sinensis Leaf Quality.
Front Plant Sci2016Study53 influential citationsThe tea plant [Camellia sinensis (L.) O. Kuntze] is an important commercial crop rich in bioactive ingredients, especially catechins, caffeine, theanine and other free amino acids, which the quality of tea leaves depends on. Drought is the…
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 Nutr2020n=9systematic51 influential citationsThe green tea amino acid, L-theanine (L-THE) is associated with several health benefits, including improvements in mood, cognition and a reduction of stress and anxiety-like symptoms. This systematic review evaluated the effect of pure…
Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis.
Nutr Rev2014n=11meta46 influential citationsA systematic review and meta-analysis was conducted on 11 randomized placebo-controlled human studies of acute effects of tea constituents L-theanine and epigallocatechin gallate, administered alone or in combination with caffeine, on…
Frequently asked
Which population does the evidence apply to?
Are there safety considerations for L-Theanine?
Related articles
Caffeine and L-Theanine - Combination or Single Ingredient?
L-theanine can counteract the negative effects of caffeine. A meta-analysis found a +8% strength gain. However, data is limited to few studies.
Which self-optimization products do you recommend for more energy and focus?
Three products are proven for acutely boostable energy and focus: caffeine 100-200 mg (effect in 30-45 min, half-life 5 h), caffeine + L-theanine 200 mg (smoother alertness, less jitter), creatine monohydrate 3-5 g/day (cognition under sleep deprivation, effect after 2-4 weeks). Pre-workout blends and 'nootropic stacks' without transparent dosing are usually expensive marketing packages with stimulants.
Caffeine + L-Theanine: Effects, Dosage, and Evidence at a Glance
What does Caffeine + L-Theanine really do? An evidence-based overview of effects, dosage, safety, and the state of the research — clearly separated into what is established and what remains speculative.
L-Theanine + Caffeine: The Focus Stack with RCT Evidence
L-Theanine plus caffeine can improve attention and reaction time in some RCTs; often, sleep, light, and movement come first, then 100 mg caffeine plus 200 mg L-Theanine.
More topics in Cognition
Bacopa Monnieri
Memory, Bacosides, Long-term Effect and Tolerance
Acetyl-L-Carnitine (ALCAR)
Mitochondria, neuroprotection, and energy metabolism.
Acetylcholine
Memory, attention, REM sleep, choline sources.
Active Recall
Retrieval over rereading — a scientifically superior way to learn.
Alpha-GPC
Choline source for acetylcholine and cognitive performance
Binaural Beats
Auditory frequency stimulation — mixed evidence.
Blood-Brain Barrier
Selective permeability, substance passage, inflammation-driven leakiness.
Brain Fog
Multifactorial: sleep, blood sugar, inflammation, thyroid, long COVID.
Caffeine
Adenosine-receptor antagonist, tolerance, timing, half-life, genetics.
Citicoline (CDP-Choline)
Phospholipid synthesis, ADHD, and neurological applications.
Creatine
More than just sport: memory, sleep deprivation, vegan deficits.
Deep Work
Focused, distraction-free work as a trainable skill.
Dopamine
Motivation, reward, movement, learning — the brain's core reward chemistry.
Dopamine Detox
A popular trend without strong scientific backing — what still holds up.
Exercise & Learning
BDNF, the hippocampus, cognitive reserve — exercise makes you sharper.
Flow State
Optimal state of consciousness during full immersion — conditions and triggers.
Ginkgo Biloba
Microcirculation, memory, and dementia interactions.
Glucose vs Ketones
The brain's fuel sources, ketogenic adaptation, cognitive effects.
Histamine
Wakefulness, allergy, histamine intolerance and brain fog.
L-Tyrosine
Dopamine precursor, stress performance and sleep deprivation
Related topics from other worlds
Inflammaging
Chronic low-grade inflammation with aging — drivers and countermeasures.
Polyphenols
Plant compounds — hormesis, mitochondrial protection, the microbiome.
Stem Cells
Clinical applications, hype, off-label risks abroad.
Whole-Body MRI
Hype vs. reality — overdiagnosis, the benefit-risk trade-off.
Caffeine & Anxiety
Adenosine antagonism, individual sensitivity, cut-off strategies.
EMDR / Trauma Therapy
PTSD, eye movements, and study effectiveness.