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L-Theanine 200 mg

California Gold Nutrition
4.7
★ ★ ★ ★ ★
(17164 ratings)
Theanine 200 mg
Product Image
Score85
A substantial 200 mg capsule combines focused calm support with excellent value. Generic sourcing and single-pathway coverage are its main limits.
How scoring works
Quantity:60 Capsule(s) • (60 servings)
Goals:
Stress Relief
Mental Focus
Brain Health
Cognitive Support
Mood Support
Productivity Boost
Sleep Support

Score 85

A substantial 200 mg capsule combines focused calm support with excellent value. Generic sourcing and single-pathway coverage are its main limits.
How scoring works

Also available as

1 option
100.00mg • 60 Capsule(s) servings Theanine 100 mg • 60 Capsule(s) • 60 servings $9.43 ($0.15 per serving)
$10.06($0.16 per serving)
iHerb
$ 10.06
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Analysis

A one-capsule 200 mg L-theanine serving offers substantial calm-attention support at excellent active efficiency. The single-active design is easy to assess and avoids low-dose additions.

It fits acute stress, tension-related distraction, and mental relaxation before sleep. Standalone theanine does not directly increase alertness or cover memory, circadian timing, or broad mood pathways.

One capsule per serving and extensive aggregate feedback strengthen its everyday appeal. The generic source has no stated purity standard, and inactive ingredients were not supplied.

Who is it for
  • Adults seeking economical 200 mg theanine
  • People whose focus declines under stress
  • Users who want one capsule per serving
Best for
  • Stress relief
  • Calm concentration
  • Pre-sleep relaxation

Pros

  • Substantial 200 mg amount
  • One-capsule serving
  • Excellent active efficiency
  • Extensive aggregate feedback

Cons

  • Generic source
  • Inactive ingredients were not supplied
  • No complementary cognitive or sleep active

Nutrient quality

94 Highest impact

L-theanine is a defined amino acid, although no branded source or purity marker is supplied. The L-theanine amount is well aligned with common calming and focus use.

.

Ingredient transparency

81 Highest impact

Every supplied active ingredient has a specific amount. No proprietary blend hides a meaningful active dose.

.

Customer satisfaction

68 High impact

The supplied aggregate rating is strong, although no specific comments are included. The large rating count makes the aggregate result relatively stable.

.

Value for money

96 Highest impact

Formula quality provides strong support for the product positioning. Dose-adjusted serving value appears strong, while the formula avoids obvious low-value padding.

.
Report analysis

Goals

Stress Relief
Stress Relief
Impact
Highest effect
A Goal FitA+ Strength of SupportC+ CoverageA+ Formula Quality
Theanine · 200 mg

L-theanine at 200 mg directly supports calm attention without acting as a sedative. Human evidence supports reduced stress responses and improved relaxation in some users.

The individual amount is clearly disclosed in a simple capsule. A single active provides focused nervous-system support but does not address cortisol or foundational mineral pathways.

Study evidence
Theanine Supportive 16 studies
Mental Focus
Mental Focus
Impact
Highest effect
B+ Goal FitA+ Strength of SupportD+ CoverageA+ Formula Quality
Theanine · 200 mg

L-theanine at 200 mg may promote calm attention without acting as a stimulant. Evidence is more consistent for relaxation and for pairing with caffeine than for large attention gains when used alone.

The amount is well aligned with commonly studied use and is fully disclosed. The single-active design is transparent, though no branded source or purity standard is given.

Study evidence
Theanine Supportive 19 studies
Brain Health
Brain Health
Impact
Highest effect
B- Goal FitA+ Strength of SupportC CoverageA+ Formula Quality

L-theanine at 200 mg may support calm attention and reduce distraction from mental tension. Its cognitive role is useful but narrower than ingredients aimed at memory, neuronal structure, or brain energy.

The single amount is fully disclosed and substantial enough to avoid token dosing. A focused capsule may suit calm concentration, but it does not provide broad long-term brain support.

Study evidence
Theanine Supportive 17 studies
Cognitive Support
Cognitive Support
Impact
Highest effect
B- Goal FitA+ Strength of SupportC CoverageA+ Formula Quality
Theanine · 200 mg

L-theanine at 200 mg may support calm attention and reduce distraction from mental tension. Its cognitive role is useful but narrower than ingredients aimed at memory, neuronal structure, or brain energy.

The single amount is fully disclosed and substantial enough to avoid token dosing. A focused capsule may suit calm concentration, but it does not provide broad long-term brain support.

Study evidence
Theanine Supportive 25 studies
Mood Support
Mood Support
Impact
Highest effect
B+ Goal FitA Strength of SupportD+ CoverageA Formula Quality

L-theanine provides a focused calming active that may reduce stress without strong sedation. The formula does not address serotonin precursors, adaptogens, or mineral pathways.

The 200 mg amount is well aligned with commonly used supplemental dosing. A single-ingredient design makes the dose easy to assess.

Study evidence
Theanine Supportive 12 studies
Productivity Boost
Productivity Boost
Impact
Highest effect
B+ Goal FitA Strength of SupportD+ CoverageA Formula Quality
Theanine · 200 mg

L-theanine is supplied at a useful amount for calm, steady attention. The simple label makes the dose easy to verify.

The effect is likely gentler than a formula that also supports alertness or mental energy. Generic sourcing without a purity or standardization claim leaves some quality uncertainty.

Study evidence
Theanine Supportive 5 studies
Sleep Support
Sleep Support
Impact
High effect
B- Goal FitA- Strength of SupportC- CoverageA Formula Quality
Theanine · 200 mg

The fully disclosed L-theanine amount may support mental relaxation and help users settle before sleep. A simple capsule provides a practical fixed serving.

No branded source or purity testing is stated, which limits confidence in raw-material quality. The focused formula offers good depth for calm attention but does not cover circadian timing or mineral support.

Study evidence
Theanine Supportive 8 studies

Ingredients

IngredientAmount per serving
L-Theanine
200 mg
Gluten Free Adults 18–50 Dairy Free
Report overview
Theanine · 200 mg OverallScore92
B+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyA+ Value

The 200 mg dose sits in the useful range for relaxation or focused attention. Its straightforward single-ingredient label makes the active amount easy to verify. The cost per active amount is especially favorable, though no branded source or purity testing is disclosed.

View ingredientView products
Loading alternative details
87 Performance

L-Theanine 200 mg Double Strength

Swanson
<p>200 mg of clearly identified branded L-theanine gives the formula a clear and relevant foundation. The branded source provides clearer ingredient identity than the original generic theanine listing.</p>
85 Performance

L-Theanine 150 mg

Solgar
<p>150 mg of clearly identified branded L-theanine gives the formula a clear and relevant foundation. The branded source provides clearer ingredient identity than the original generic theanine listing.</p>
87 Performance

L-Theanine 100 mg

California Gold Nutrition
<p>100 mg of clearly identified branded L-theanine gives the formula a clear and relevant foundation. The branded source provides clearer ingredient identity than the original generic theanine listing.</p>
85 Budget

Double Strength L-Theanine 200 mg

NOW
<p>A lower serving cost comes with 200 mg of clearly stated l-theanine. The ingredient profile remains focused on theanine and offers a practical alternative to the original formula.</p>
84 Budget

L-Theanine 200 mg

Advance Physician Formulas
<p>A lower serving cost comes with 200 mg of clearly stated l-theanine. The ingredient profile remains focused on theanine and offers a practical alternative to the original formula.</p>
83 Budget

L-Theanine 100 mg

California Gold Nutrition
<p>A lower serving cost comes with 100 mg of clearly stated l-theanine. The ingredient profile remains focused on theanine and offers a practical alternative to the original formula.</p>
85 Value

L-Theanine 100 mg

NOW
<p>100 mg of clearly stated L-theanine is paired with favorable serving-level value in the supplied data. The ingredient profile remains focused on theanine and offers a practical alternative to the original formula.</p>
84 Value

Suntheanine L-Theanine 125 mg

Natural Factors Stress-Relax
<p>250 mg of clearly identified branded L-theanine is paired with favorable serving-level value in the supplied data. The branded source provides clearer ingredient identity than the original generic theanine listing.</p>
82 Value

Theanine 100 mg

Jarrow Formulas
<p>100 mg of clearly stated L-theanine is paired with favorable serving-level value in the supplied data. The ingredient profile remains focused on theanine and offers a practical alternative to the original formula.</p>
Report alternatives

Sources

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

  1. 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
  2. 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 pooledStress Relief Mood Support forTheanine
  3. 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 participantsStress Relief Sleep Support forTheanine
  4. 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 Brain Health forTheanine
  5. 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 Mood Support forTheanine
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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
  21. 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
  22. 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
  23. 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