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L-Theanine 100 mg

NOW
4.7
★ ★ ★ ★ ★
(17078 ratings)
Theanine 100 mg
Green Tea 250 mg
Product Image
Score85
A simple, good-value 100 mg theanine capsule with an unstandardized decaffeinated green tea addition.
How scoring works
Quantity:90 Capsule(s) • (90 servings)
Goals:
Stress Relief
Brain Health
Mood Support
Sleep Support
Productivity Boost
Cognitive Support
Mental Focus

Score 85

A simple, good-value 100 mg theanine capsule with an unstandardized decaffeinated green tea addition.
How scoring works
$12.70($0.14 per serving)
Pure Formulas
$ 13.08
iHerb
$ 13.46
Vitacost
$ 14.37
Daily Vita
$ 12.70
Amazon
$ 12.70
iHerb
$ 13.46
Report prices

Analysis

The capsule supplies 100 mg L-theanine, an amount suitable for mild calm-focus or evening use. Decaffeinated green tea adds 250 mg of tea material without a stated caffeine amount.

The formula remains focused and easy to understand. Green tea is not standardized for catechins or EGCG, so its contribution beyond theanine cannot be measured.

The product fits stress, focus, or sleep routines better than the many broader listed goals. Individual response to 100 mg theanine can vary, and some users may prefer a higher dose.

Who is it for
  • Adults seeking calm focus
  • People wanting a mild evening relaxation supplement
Best for
  • Stress support
  • Mental focus
  • Sleep preparation

Pros

  • Provides 100 mg L-theanine
  • Includes decaffeinated green tea
  • Simple and economical formula

Cons

  • Green tea catechins are not quantified
  • Residual caffeine is not stated
  • May be mild for some users

Warnings

  • People highly sensitive to caffeine should verify residual caffeine in the decaffeinated green tea.

Nutrient quality

88 Highest impact

L-theanine is an appropriate active form, while the green tea lacks catechin or EGCG standardization. Theanine reaches a practical effective starting amount, but the active contribution from green tea is unknown.

Ingredient transparency

81 Highest impact

Theanine and green tea amounts are individually stated. Excipients and daily directions are absent from the supplied data, which leaves some label details uncertain.

Customer satisfaction

71 High impact

The aggregate satisfaction average is strong, though no detailed feedback is supplied. The very large volume makes the aggregate satisfaction signal stable.

Value for money

97 Highest impact

A meaningful theanine dose and simple formula provide strong quality for the cost. The serving offers excellent cost efficiency for the disclosed theanine amount.

Report analysis

Goals

Stress Relief
Stress Relief
Impact
Highest effect
A- Goal FitB+ Strength of SupportC+ CoverageA- Formula Quality
Theanine · 100 mg

L-theanine provides direct, non-sedating support for a calmer mental state, while decaffeinated green tea supplies a compatible botanical context. The formula is well suited to acute daytime stress without adding a stimulant load.

The L-theanine amount reaches the usual effective starting range and is individually disclosed. Generic sourcing and absent purity information are the main limitations.

Study evidence
Theanine Supportive 16 studies
Brain Health
Brain Health
Impact
High effect
B+ Goal FitB+ Strength of SupportC CoverageA Formula Quality

L-theanine at 100 mg supports calm attention, while decaffeinated green tea adds related polyphenols without significant stimulation. The combination is simple and suitable for mental resilience.

Green tea lacks catechin or EGCG standardization, so its cognitive contribution cannot be quantified. The product remains focused on calm attention rather than memory, neuronal energy, or structural brain support.

Study evidence
Theanine Supportive 17 studies
Mood Support
Mood Support
Impact
High effect
B- Goal FitB Strength of SupportC- CoverageA+ Formula Quality

L-theanine offers direct support for calm mood and reduced tension without relying on stimulation. Decaffeinated green tea provides a compatible source context but little additional mood coverage.

The amount is practical and fully disclosed, although branded purity information is absent. The streamlined formula provides strong depth for a single calming pathway.

Study evidence
Theanine Supportive 12 studies
Sleep Support
Sleep Support
Impact
High effect
C+ Goal FitA- Strength of SupportC CoverageB+ Formula Quality
Theanine · 100 mg

L-theanine is provided at a useful amount for easing mental tension before bed. Its sleep role is supportive rather than sedating, and evidence is more modest than for direct circadian agents.

The amount and active L-isomer are clearly stated in one capsule. Decaffeinated green tea is compatible, though it adds little proven sleep support beyond the theanine.

Study evidence
Theanine Supportive 8 studies
Productivity Boost
Productivity Boost
Impact
High effect
B Goal FitB+ Strength of SupportD+ CoverageB+ Formula Quality
Theanine · 100 mg

L-Theanine may support calm attention, especially alongside a separate caffeine source, but it does not provide alertness by itself. Theanine has credible human evidence for relaxed attention and for smoothing stimulant-related tension.

The 100 mg amount reaches a practical effective threshold for focused calm. Decaffeinated green tea is a sensible companion to theanine and avoids a hidden stimulant load.

Study evidence
Theanine Supportive 5 studies
Cognitive Support
Cognitive Support
Impact
High effect
B Goal FitB Strength of SupportC- CoverageB+ Formula Quality
Green Tea · 250 mgTheanine · 100 mg

L-theanine may support relaxed attention and reduce distraction from stress without acting as a strong sedative. Decaffeinated green tea adds a related botanical source, but its catechin and residual caffeine content are not stated.

The theanine amount is meaningful and clearly disclosed, giving the calming-attention pathway useful depth. The formula does not provide a strong memory, circulation, or neuro-regenerative active.

Study evidence
Green Tea Supportive 32 studies
Theanine Supportive 25 studies

Ingredients

IngredientAmount per serving
L-Theanine
100 mg
decaffeinated Green Tea
250 mg
Gluten Free Adults 18–50 Vegan Kosher Dairy Free Vegetarian
Report overview
Theanine · 100 mg OverallScore92
B+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyA+ Value

The 100 mg L-Theanine serving is clearly labeled and falls within the optimal range. Generic sourcing provides no added purity assurance, though the form itself is appropriate. Low cost per active amount makes it highly efficient.

View ingredientView products
Green Tea · 250 mg OverallScore18
F Active Ingredient Quality & BioavailabilityD- Dose, Safety & Label TransparencyF Value

The green tea is explicitly decaffeinated, which supports stimulant-sensitive use. Its extract or powder form and active-marker content are not disclosed, and no absorption support is listed. EGCG-specific effectiveness and value therefore remain uncertain.

View ingredientView products
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83 Performance

L-Theanine 200 mg

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<p>Suntheanine offers strong ingredient assurance at a meaningful amount for calm focus. Compared with the original, the Theanine profile keeps the ingredient match close while the more coherent or clearly disclosed formula provides the main quality advantage.</p>
87 Performance

L-Theanine 200 mg Double Strength

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<p>Branded Suntheanine is supplied at a substantial amount that suits calm attention and relaxation. Compared with the original, the Theanine profile keeps the ingredient match close while the more coherent or clearly disclosed formula provides the main quality advantage.</p>
85 Performance

L-Theanine 150 mg

Solgar
<p>A useful Suntheanine amount combines meaningful calm-focus support with strong ingredient identity. Compared with the original, the Theanine profile keeps the ingredient match close while the more coherent or clearly disclosed formula provides the main quality advantage.</p>
85 Budget

Double Strength L-Theanine 200 mg

NOW
<p>A meaningful L-theanine amount supports calm focus, relaxation, and stress-related concentration. Compared with the original, its Theanine overlap preserves the intended ingredient focus at a lower serving cost, although the stated limitations still matter.</p>
80 Budget

Green Tea

Jarrow Formulas
<p>A concentrated green-tea extract identifies catechins, polyphenols, and EGCG, supporting substantial antioxidant exposure. Compared with the original, its Green Tea overlap preserves the intended ingredient focus at a lower serving cost, although the stated limitations still matter.</p>
84 Budget

L-Theanine 200 mg

Advance Physician Formulas
<p>L-theanine is a defined amino acid, although no branded source or purity marker is supplied. The eligible list does not provide three lower-cost choices from distinct brands; this is a close fallback, but its serving cost is not lower than the original.</p>
87 Value

L-Theanine 100 mg

California Gold Nutrition
<p>AlphaWave L-theanine provides a clearly disclosed 100 mg amount suited to calm focus and relaxation. Compared with the original, the Theanine alignment and practical serving economics create a more balanced value trade-off, with the stated caveats in mind.</p>
81 Value

Suntheanine L-Theanine 100 mg

Natural Factors Stress-Relax
<p>Suntheanine L-theanine provides a clearly disclosed 200 mg amount suited to calm focus and relaxation. Compared with the original, the Theanine alignment and practical serving economics create a more balanced value trade-off, with the stated caveats in mind.</p>
82 Value

L-Theanine 200 mg

DaVinci Laboratories
<p>Suntheanine L-theanine provides a clearly disclosed 200 mg amount suited to calm focus and relaxation. Compared with the original, the Theanine alignment and practical serving economics create a more balanced value trade-off, with the stated caveats in mind.</p>
Report alternatives

Sources

Published studies used for the product analysis and the top-ranked studies for each ingredient and goal.

  1. Promising, but Not Completely Conclusive-The Effect of l-Theanine on Cognitive Performance Based on the Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Clinical Trials.
    Mátyus RO; Szikora Z; Bodó D; Vargáné Szabó B; Csupor É; Csupor D; Tóth B · Journal of clinical medicine · 2025
    Meta-analysis148 participants5 studies pooledMental Focus forTheanine
  2. Safety and Efficacy of AlphaWave® L-Theanine Supplementation for 28 Days in Healthy Adults with Moderate Stress: A Randomized, Double-Blind, Placebo-Controlled Trial.
    Moulin M; Crowley DC; Xiong L; Guthrie N; Lewis ED · Neurology and therapy · 2024
    Randomized trial30 participantsMental Focus Productivity Boost Stress Relief forTheanine
  3. 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.
    Dodd FL; Kennedy DO; Riby LM; Haskell-Ramsay CF · Psychopharmacology · 2016
    Randomized trial24 participantsMental Focus forTheanine
  4. Green tea and coffee intake and risk of cognitive decline in older adults: the National Institute for Longevity Sciences, Longitudinal Study of Aging.
    Shirai Y; Kuriki K; Otsuka R; Kato Y; Nishita Y; Tange C; Tomida M; Imai T; Ando F; Shimokata H · Public health nutrition · 2021
    Cohort study1,305 participantsAnti-Aging forGreen Tea
  5. Associations of green tea, coffee, and soft drink consumption with longitudinal changes in leukocyte telomere length.
    Sohn I; Shin C; Baik I · Scientific reports · 2023
    Cohort study1,952 participantsAnti-Aging forGreen Tea
  6. Can teatime increase one's lifetime?
    Nakachi K; Eguchi H; Imai K · Ageing research reviews · 2003
    Cohort studyAnti-Aging forGreen Tea
  7. Influences of tea consumption on self-rated health and life satisfaction among older adults: Evidence from the CLHLS.
    Zou M; Sun C; Yang M; Li C; Wang S; Zheng D; Wang J; Yu L; Sun L; Wang Y; Chen H; Zeng Y · PsyCh journal · 2025
    Cohort study78,345 participantsAnti-Aging forGreen Tea
  8. Double-blinded, placebo-controlled trial of green tea extracts in the clinical and histologic appearance of photoaging skin.
    Chiu AE; Chan JL; Kern DG; Kohler S; Rehmus WE; Kimball AB · Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.] · 2005
    Randomized trial40 participantsAnti-Aging forGreen Tea
  9. The effects of green tea on acne vulgaris: A systematic review and meta-analysis of randomized clinical trials.
    Kim S; Park TH; Kim WI; Park S; Kim JH; Cho MK · Phytotherapy research : PTR · 2021
    Meta-analysis247 participants5 studies pooledAnti-Inflammatory Support forGreen Tea
  10. Green Tea Catechin Association with Ultraviolet Radiation-Induced Erythema: A Systematic Review and Meta-Analysis.
    Kapoor MP; Sugita M; Fukuzawa Y; Timm D; Ozeki M; Okubo T · Molecules (Basel, Switzerland) · 2021
    Meta-analysis100 participants6 studies pooledAnti-Inflammatory Support forGreen Tea
  11. Efficacy of (-)-epigallocatechin gallate delivered by a new-type scaler tip during scaling and root planing on chronic periodontitis: a split-mouth, randomized clinical trial.
    Wang Y; Zeng J; Yuan Q; Luan Q · BMC oral health · 2021
    Randomized trial20 participantsAnti-Inflammatory Support forGreen Tea
  12. Camellia Sinensis Mouthwashes in Oral Care: a Systematic Review.
    Tafazoli A; Tafazoli Moghadam E · Journal of dentistry (Shiraz, Iran) · 2020
    Systematic review69 studies pooledAnti-Inflammatory Support forGreen Tea
  13. Skin photoprotection by green tea: antioxidant and immunomodulatory effects.
    Katiyar SK · Current drug targets. Immune, endocrine and metabolic disorders · 2004
    Narrative reviewAnti-Inflammatory Support forGreen Tea
  14. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial.
    Hidese S; Ogawa S; Ota M; Ishida I; Yasukawa Z; Ozeki M; Kunugi H · Nutrients · 2020
    Randomized trial30 participantsBrain Health Cognitive Support Sleep Support forTheanine
  15. A Randomized, Triple-Blind, Placebo-Controlled, Crossover Study to Investigate the Efficacy of a Single Dose of AlphaWave® L-Theanine on Stress in a Healthy Adult Population.
    Evans M; McDonald AC; Xiong L; Crowley DC; Guthrie N · Neurology and therapy · 2021
    Randomized trialBrain Health Stress Relief forTheanine
  16. 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.
    Payne ER; Aceves-Martins M; Dubost J; Greyling A; de Roos B · Nutrition reviews · 2025
    Meta-analysis50 studies pooledBrain Health Cognitive Support Mental Focus forTheanine
  17. Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task.
    Foxe JJ; Morie KP; Laud PJ; Rowson MJ; de Bruin EA; Kelly SP · Neuropharmacology · 2012
    Randomized trial27 participantsBrain Health Cognitive Support forTheanine
  18. Effects of l-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study.
    Baba Y; Inagaki S; Nakagawa S; Kaneko T; Kobayashi M; Takihara T · Journal of medicinal food · 2021
    Randomized trialBrain Health Mental Focus Productivity Boost forTheanine
  19. Safety and efficacy of cognitive training plus epigallocatechin-3-gallate in young adults with Down's syndrome (TESDAD): a double-blind, randomised, placebo-controlled, phase 2 trial.
    de la Torre R; de Sola S; Hernandez G; Farré M; Pujol J; Rodriguez J; Espadaler JM; Langohr K; Cuenca-Royo A; Principe A; Xicota L; Janel N; Catuara-Solarz S; Sanchez-Benavides G; Bléhaut H; Dueñas-Espín I; Del Hoyo L; Benejam B; Blanco-Hinojo L; Videla S; Fitó M; Delabar JM; Dierssen M; TESDAD study group · The Lancet. Neurology · 2017
    Randomized trial87 participantsCognitive Support forGreen Tea
  20. Association between tea consumption and risk of cognitive disorders: A dose-response meta-analysis of observational studies.
    Liu X; Du X; Han G; Gao W · Oncotarget · 2018
    Meta-analysis48,435 participants17 studies pooledCognitive Support forGreen Tea
  21. Investigating the Impact of Tea Consumption on Cognitive Function and Exploring Tea-Genetic Interactions in Older Adults Aged 65-105 Years: Findings from the 2002-2018 CLHLS Data.
    Yu L; Yang M; Ye KX; Li C; Zou M; Wang J; Yuan X; Zheng D; Sun C; Zhang Y; Feng Q; Maier AB; Sun L; Feng L; Wang Y; Chen H; Zeng Y · The journal of prevention of Alzheimer's disease · 2024
    Cohort study76,270 participantsCognitive Support forGreen Tea
  22. Consumption of green tea, but not black tea or coffee, is associated with reduced risk of cognitive decline.
    Noguchi-Shinohara M; Yuki S; Dohmoto C; Ikeda Y; Samuraki M; Iwasa K; Yokogawa M; Asai K; Komai K; Nakamura H; Yamada M · PloS one · 2014
    Cohort study490 participantsCognitive Support forGreen Tea
  23. Green Tea Consumption and the Risk of Incident Dementia in Elderly Japanese: The Ohsaki Cohort 2006 Study.
    Tomata Y; Sugiyama K; Kaiho Y; Honkura K; Watanabe T; Zhang S; Sugawara Y; Tsuji I · The American journal of geriatric psychiatry : official journal of the American Association for Geriatric Psychiatry · 2018
    Cohort study13,645 participantsCognitive Support forGreen Tea
  24. Dose-response effect of L-theanine on psychomotor speed, sustained attention, and inhibitory control: a double-blind, placebo-controlled, crossover study.
    Dassanayake TL; Wijesundara D; Kahathuduwa CN; Weerasinghe VS · Nutritional neuroscience · 2023
    Randomized trial32 participantsCognitive Support forTheanine
  25. Acute effects of theanine, caffeine and theanine-caffeine combination on attention.
    Kahathuduwa CN; Dassanayake TL; Amarakoon AMT; Weerasinghe VS · Nutritional neuroscience · 2018
    Clinical trial20 participantsCognitive Support Mental Focus forTheanine
  26. Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials.
    Khalesi S; Sun J; Buys N; Jamshidi A; Nikbakht-Nasrabadi E; Khosravi-Boroujeni H · European journal of nutrition · 2015
    Meta-analysis13 studies pooledHeart Health forGreen Tea
  27. Effect of Green Tea on Blood Pressure in Healthy Individuals: A Meta-Analysis.
    Yıldırım Ayaz E; Dincer B; Mesci B · Alternative therapies in health and medicine · 2023
    Meta-analysis680 participants9 studies pooledHeart Health forGreen Tea
  28. Green tea extract reduces blood pressure, inflammatory biomarkers, and oxidative stress and improves parameters associated with insulin resistance in obese, hypertensive patients.
    Bogdanski P; Suliburska J; Szulinska M; Stepien M; Pupek-Musialik D; Jablecka A · Nutrition research (New York, N.Y.) · 2012
    Randomized trial56 participantsHeart Health forGreen Tea
  29. Green tea intake lowers fasting serum total and LDL cholesterol in adults: a meta-analysis of 14 randomized controlled trials.
    Zheng XX; Xu YL; Li SH; Liu XX; Hui R; Huang XH · The American journal of clinical nutrition · 2011
    Meta-analysis1,136 participants14 studies pooledHeart Health forGreen Tea
  30. Effects of green tea on lipid profile in overweight and obese women.
    Li A; Wang Q; Li P; Zhao N; Liang Z · International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition · 2024
    Meta-analysis1,818 participants15 studies pooledHeart Health forGreen Tea
  31. Effect of L-theanine on selective attention in a traffic-related reaction task in sleep-deprived young adults: a double-blind placebo-controlled, crossover study.
    Karunaratne UW; Dassanayake TL · Nutritional neuroscience · 2025
    Randomized trial24 participantsMental Focus forTheanine
  32. l-theanine adjunct to sertraline for major depressive disorder: A randomized, double-blind, placebo-controlled clinical trial.
    Shamabadi A; Kafi F; Arab Bafrani M; Asadigandomani H; A Basti F; Akhondzadeh S · Journal of affective disorders · 2023
    Randomized trial60 participantsMood Support forTheanine
  33. 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.
    Ritsner MS; Miodownik C; Ratner Y; Shleifer T; Mar M; Pintov L; Lerner V · The Journal of clinical psychiatry · 2011
    Randomized trial60 participantsMood Support Stress Relief forTheanine
  34. The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review.
    Williams JL; Everett JM; D'Cunha NM; Sergi D; Georgousopoulou EN; Keegan RJ; McKune AJ; Mellor DD; Anstice N; Naumovski N · Plant foods for human nutrition (Dordrecht, Netherlands) · 2020
    Systematic review9 studies pooledMood Support forTheanine
  35. Comparison of the effects of two amino acids, Gamma-aminobutyric acid (GABA) and L-theanine, on sedation, anxiety, and cognition in preoperative surgical patients - A randomized controlled study.
    Deshpande SS; Kurdi M; Baiju A; Athira AS; Sarasamma AG; Gangadharan AK · Journal of anaesthesiology, clinical pharmacology · 2025
    Randomized trial168 participantsMood Support Stress Relief forTheanine
  36. Anti-stress effect of theanine on students during pharmacy practice: positive correlation among salivary α-amylase activity, trait anxiety and subjective stress.
    Unno K; Tanida N; Ishii N; Yamamoto H; Iguchi K; Hoshino M; Takeda A; Ozawa H; Ohkubo T; Juneja LR; Yamada H · Pharmacology, biochemistry, and behavior · 2014
    Randomized trial20 participantsMood Support forTheanine
  37. Cognitive and affective effects of L-Theanine: a systematic review and meta-analysis of 31 randomized trials.
    Gerolymos C; Saddier E; Boyer L; Fond G · Molecular psychiatry · 2026
    Meta-analysis1,168 participants31 studies pooledProductivity Boost forTheanine
  38. Effects of L-theanine on cognition, mood and sleep: evidence from human trials.
    Cotter J; Kilpatrick HE · Frontiers in nutrition · 2026
    Narrative reviewProductivity Boost forTheanine
  39. Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together.
    Rogers PJ; Smith JE; Heatherley SV; Pleydell-Pearce CW · Psychopharmacology · 2008
    Randomized trial48 participantsProductivity Boost forTheanine
  40. Comparison Between Efficacy of Oral Melatonin and Oral L-theanine in Improving Sleep in Cancer Patients Suffering From Insomnia: A Randomised Double-blinded Placebo-controlled Study.
    Kurdi MS; As A; Ladhad DA; Mitragotri MV; Baiju A · Indian journal of palliative care · 2024
    Randomized trial120 participantsSleep Support forTheanine
  41. The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis.
    Bulman A; D'Cunha NM; Marx W; Turner M; McKune A; Naumovski N · Sleep medicine reviews · 2025
    Meta-analysis897 participants19 studies pooledSleep Support forTheanine
  42. In Search of a Safe Natural Sleep Aid.
    Rao TP; Ozeki M; Juneja LR · Journal of the American College of Nutrition · 2016
    Narrative reviewSleep Support forTheanine
  43. L-theanine in the adjunctive treatment of generalized anxiety disorder: A double-blind, randomised, placebo-controlled trial.
    Sarris J; Byrne GJ; Cribb L; Oliver G; Murphy J; Macdonald P; Nazareth S; Karamacoska D; Galea S; Short A; Ee C; Birling Y; Menon R; Ng CH · Journal of psychiatric research · 2020
    Randomized trial46 participantsSleep Support forTheanine
  44. Anti-Stress, Behavioural and Magnetoencephalography Effects of an L-Theanine-Based Nutrient Drink: A Randomised, Double-Blind, Placebo-Controlled, Crossover Trial.
    White DJ; de Klerk S; Woods W; Gondalia S; Noonan C; Scholey AB · Nutrients · 2016
    Randomized trial34 participantsStress Relief forTheanine