L-Theanine for Anxiety
Amino acid from tea leaves that crosses the blood-brain barrier and increases alpha-wave brain activity; promotes calm alertness without sedation, often paired with caffeine.
L-Theanine for Anxiety
9 of 9 results reported a benefit, from 2 published studies.
2 studies, including a review of trials · the chart counts everything measured
- 9 reported a benefit
Colour keyReported a benefitNo clear benefitUnclearPossible harmAmber is for highlights, such as where the most research is. It never means a result was good.
- Stress and anxietyReported a benefitmeasurement not reportedL-theanine at 200-400 mg/day may reduce stress and anxiety compared to control in people exposed to stressful conditions.1 review of trials2020 study ↗
- Anxiety symptomsReported a benefitsee exact figuresAnxiety scores decreased after four weeks of L-theanine vs placebo in 30 people.1 randomised trial2019 study ↗
Also measured in these studies (4)
These were measured alongside, but they are not what this condition is about.
- Depression symptomsReported a benefitsee exact figuresDepression scores decreased after four weeks of L-theanine vs placebo in 30 people.1 randomised trial2019 study ↗
- Planning and problem-solving skillsReported a benefitsee exact figuresExecutive function scores improved after four weeks of L-theanine vs placebo in 30 people.1 randomised trial2019 study ↗
- Sleep qualityReported a benefitSleep quality scores decreased after four weeks of L-theanine vs placebo in 30 people.1 randomised trial · no comparable figure reported2 of 2 results reported a benefit2019 study ↗
- Verbal fluency (word-finding)Reported a benefitVerbal fluency scores improved after four weeks of L-theanine vs placebo in 30 people.1 randomised trial · no comparable figure reported3 of 3 results reported a benefit2019 study ↗
These are the figures the studies reported, not a prediction for any one person. Where several studies measured the same thing in the same unit, we show a simple average and say so. Every result is listed below.
See every resultThe connection
Generalised anxiety, social anxiety and panic disorder.
Also known as: Theanine, L-gamma-glutamylethylamide
L-Theanine × Anxiety: at a glance
Every published result for this pair, extracted and audited.
These charts count reported findings from published studies, grouped by reported benefit and study design. Study design is not a certainty grade.
L-Theanine / Anxiety: reported findings; one study may contribute several findings.
What the evidence shows
What this means: Counts describe research quantity, not treatment effectiveness or certainty.
| Category | Findings (count) |
|---|---|
| Benefit | 9 |
Study designs behind these findings
What this means: Counts describe research quantity, not treatment effectiveness or certainty.
| Category | Findings (count) |
|---|---|
| Systematic review | 1 |
| Randomised trial | 8 |
- Studies
- 2
| Study | Outcome | Reported result | Uncertainty (as reported) | Study duration |
|---|---|---|---|---|
| The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review. (PMID 31758301) | reduction of stress and anxiety | Not reported | Not reported | Not reported |
| Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. (PMID 31623400) | Executive function | Not reported | p = 0.031 | four weeks |
| Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. (PMID 31623400) | Letter fluency (lower half subgroup) | Not reported | p = 0.002 | four weeks |
| Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. (PMID 31623400) | Pittsburgh Sleep Quality Index | Not reported | p = 0.013 | four weeks |
| Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. (PMID 31623400) | PSQI subscale: sleep latency, sleep disturbance, use of sleep medication | Not reported | all p < 0.05 | four weeks |
| Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. (PMID 31623400) | Self-rating Depression Scale | Not reported | p = 0.019 | four weeks |
| Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. (PMID 31623400) | State-Trait Anxiety Inventory-trait | Not reported | p = 0.006 | four weeks |
| Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. (PMID 31623400) | Verbal fluency | Not reported | p = 0.001 | four weeks |
| Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. (PMID 31623400) | Verbal fluency (lower half subgroup) | Not reported | p = 0.002 | four weeks |
Study results, as reported by the publications
Every measured outcome, one row per finding - numbers exactly as reported. Units are preserved where supplied; missing units are not inferred.
| Study and type | Reported sample and duration | Outcome measured | Reported result | What studies found |
|---|---|---|---|---|
| PMID 31758301 2020 Systematic review | Sample (as reported): Not reportedDuration: Not reported | reduction of stress and anxiety | Not reported | Benefit |
| PMID 31623400 2019 Randomised trial | Sample (as reported): 30Duration: four weeks | Executive function | Not reported (p = 0.031) | Benefit |
| PMID 31623400 2019 Randomised trial | Sample (as reported): 30Duration: four weeks | Letter fluency (lower half subgroup) | Not reported (p = 0.002) | Benefit |
| PMID 31623400 2019 Randomised trial | Sample (as reported): 30Duration: four weeks | Pittsburgh Sleep Quality Index | Not reported (p = 0.013) | Benefit |
| PMID 31623400 2019 Randomised trial | Sample (as reported): 30Duration: four weeks | PSQI subscale: sleep latency, sleep disturbance, use of sleep medication | Not reported (all p < 0.05) | Benefit |
| PMID 31623400 2019 Randomised trial | Sample (as reported): 30Duration: four weeks | Self-rating Depression Scale | Not reported (p = 0.019) | Benefit |
| PMID 31623400 2019 Randomised trial | Sample (as reported): 30Duration: four weeks | State-Trait Anxiety Inventory-trait | Not reported (p = 0.006) | Benefit |
| PMID 31623400 2019 Randomised trial | Sample (as reported): 30Duration: four weeks | Verbal fluency | Not reported (p = 0.001) | Benefit |
| PMID 31623400 2019 Randomised trial | Sample (as reported): 30Duration: four weeks | Verbal fluency (lower half subgroup) | Not reported (p = 0.002) | Benefit |
L-Theanine × Anxiety: the evidence base
Hand-selected PubMed studies, linked to the originals.
Ordered by strength of evidence, then result direction.
01Efficiency of Different Supplements in Alleviating Symptoms of ADHD with or Without the Use of Stimulants: A Systematic ReviewAl Shahab S, et al. · Nutrients · 2025PMID 40362791 ↗02Transdiagnostic reduction in cortical choline-containing compounds in anxiety disorders: a (1)H-magnetic resonance spectroscopy meta-analysisMaddock RJ, et al. · Molecular psychiatry · 2025PMID 40913113 ↗03Effects of Different Cannabinoid Formulations on Anxiety-Related Disorders, and Tourette Syndrome: A Systematic Review and Meta-AnalysisRaminelli AO, et al. · Cannabis and cannabinoid research · 2025PMID 40956670 ↗04Effectiveness of Cannabidiol to Manage Chronic Pain: A Systematic ReviewMohammed SYM, et al. · Pain management nursing : official journal of the American Society of Pain Management Nurses · 2024PMID 37953193 ↗05Psychosocial and medication interventions to stop or reduce alcohol consumption during pregnancyMinozzi S, et al. · The Cochrane database of systematic reviews · 2024PMID 38682758 ↗06Therapeutic potential of cannabidiol (CBD) in anxiety disorders: A systematic review and meta-analysisHan K, et al. · Psychiatry research · 2024PMID 38924898 ↗Community experiences
Contributors volunteered; this does not establish treatment effectiveness or population incidence.
Reported changes
No publishable community breakdown is available. This does not establish that no reports exist.