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Double Strength L-Theanine 200 mg

NOW
4.7
★ ★ ★ ★ ★
(45175 ratings)
Theanine 200 mg
Product Image
Score85
A high-value, substantial theanine capsule for calm focus and stress, with little benefit from the small inositol addition.
How scoring works
Quantity:120 Capsule(s) • (120 servings)
Goals:
Stress Relief
Productivity Boost
Mental Focus
Sleep Support
Cognitive Support
Brain Health
Mood Support

Score 85

A high-value, substantial theanine capsule for calm focus and stress, with little benefit from the small inositol addition.
How scoring works

Also available as

1 option
60 servings Theanine 200 mg • 60 Capsule(s) • 60 servings $14.54 ($0.24 per serving)
$20.78($0.17 per serving)
iHerb
$ 24.13
iHerb
$ 24.13
Vitacost
$ 25.63
Daily Vita
$ 26.60
Walmart
$ 20.78
Amazon
$ 20.79
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Analysis

The capsule supplies a substantial L-theanine amount in one unit. It is well suited to calm focus, stress-related tension, or pre-sleep relaxation.

Inositol is included at a small amount that is unlikely to meaningfully broaden the formula. The theanine source is generic and carries no stated purity standard.

Strong value and simple dosing make it practical for regular use. Its calming pathway is useful but does not replace broader memory, mood, or sleep-support strategies.

Who is it for
  • Adults seeking calm without strong sedation
  • Users wanting substantial L-theanine
  • Value-focused capsule users
Best for
  • Situational stress
  • Calm focus
  • Pre-sleep relaxation

Pros

  • Substantial theanine amount
  • One-capsule serving
  • Excellent practical value
  • Large serving supply

Cons

  • Generic rather than branded source
  • No purity specification
  • Inositol amount is modest
  • Single main pathway

Warnings

  • L-theanine may feel drowsy for some users
  • Combining it with sedatives or alcohol may increase relaxation or sleepiness
  • People using blood-pressure medicines should monitor for added lightheadedness

Nutrient quality

90 Highest impact

L-theanine is an appropriate form, but no branded source or purity standard is stated. The L-theanine amount is substantial and well aligned with common focused use.

.

Ingredient transparency

84 Highest impact

Every listed active has a specific amount, which makes the core formula straightforward to assess. The supplied data omits a complete excipient list and full intake directions.

.

Customer satisfaction

72 High impact

The supplied aggregate satisfaction signal is favorable. A large amount of feedback makes that aggregate signal reasonably stable, but no narrative evidence was provided.

.

Value for money

93 Highest impact

The meaningful theanine amount and straightforward formula support strong value. A concentrated single-capsule serving provides efficient active delivery.

.
Report analysis

Goals

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

L-theanine provides targeted calm-focus support at a clearly stated 200 mg amount within the preferred range. It is well suited to daytime stress because it generally supports relaxed attention without acting as a strong sedative.

The generic source lacks branded purity verification, leaving some quality uncertainty. Inositol is complementary in theme but the 100 mg amount is far below amounts typically used for targeted mood support.

Study evidence
Theanine Supportive 16 studies
Productivity Boost
Productivity Boost
Impact
Highest effect
B+ Goal FitA Strength of SupportC+ CoverageA Formula Quality
Theanine · 200 mg

L-theanine may support calm concentration and reduce tension that interferes with work. Evidence is strongest when it is paired with caffeine, while this formula does not provide stimulation on its own.

The L-theanine amount is well aligned with common focus use and is fully disclosed. Inositol is compatible but adds little to the immediate productivity effect.

Study evidence
Theanine Supportive 5 studies
Mental Focus
Mental Focus
Impact
Highest effect
B Goal FitA+ Strength of SupportC CoverageB+ Formula Quality
Theanine · 200 mg

L-theanine can promote calm attention and may be especially useful when stress or caffeine interferes with concentration. The 200 mg amount is meaningful, although no stimulant is included to create the classic calm-alertness pairing.

Inositol is present as a modest companion with less direct evidence for acute focus. The focused formula is unlikely to help users seeking a strong immediate alertness effect.

Study evidence
Theanine Supportive 19 studies
Sleep Support
Sleep Support
Impact
High effect
C+ Goal FitA Strength of SupportC CoverageA- Formula Quality
Theanine · 200 mg

The 200 mg L-theanine amount fits the supplied preferred range and may help quiet mental tension before bed. Evidence supports relaxation more clearly than direct improvements in sleep duration or circadian timing.

The active amount is separately disclosed, though no branded source or purity verification is identified. Inositol adds little at the stated amount, leaving the formula focused mainly on one calming pathway.

Study evidence
Theanine Supportive 8 studies
Cognitive Support
Cognitive Support
Impact
High effect
B Goal FitA- Strength of SupportD+ CoverageB+ Formula Quality
Theanine · 200 mg

L-theanine directly supports calm focus and reduced mental tension without relying on stimulation. Human evidence supports relaxation and attention benefits, especially when theanine is paired with caffeine.

The 200 mg amount sits within a commonly effective range for calm-focus support. The exact amount is clear, but the source lacks branded purity or stereoisomer verification.

Study evidence
Theanine Supportive 25 studies
Brain Health
Brain Health
Impact
High effect
C+ Goal FitB+ Strength of SupportD+ CoverageB Formula Quality

L-theanine may support calm attention and mental composure without acting as a broad nootropic. Inositol adds little at the disclosed amount and does not materially expand brain-health coverage.

The 200 mg theanine amount is clearly disclosed and sits in the preferred range. Generic sourcing without purity verification limits confidence compared with a standardized branded form.

Study evidence
Theanine Supportive 17 studies
Mood Support
Mood Support
Impact
High effect
C Goal FitB+ Strength of SupportD- CoverageB- Formula Quality

L-theanine is supplied at a well-studied calming amount. The inositol addition is far below amounts commonly explored for mood or anxiety outcomes.

The formula may help short-term stress more than persistent mood regulation. Its simple pairing is coherent but covers limited pathways.

Study evidence
Theanine Supportive 12 studies

Ingredients

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

The clearly disclosed L-theanine amount falls squarely within the preferred range for relaxation or focus support. A generic source without stated purity testing limits ingredient-quality assurance compared with branded forms. The concentrated serving delivers excellent cost efficiency and requires only one capsule.

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>
82 Budget

L-Theanine

NOW
<p>A lower-cost option that also meets the remaining selection constraints was not available; this choice is among the closest and supplies 285 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-cost option that also meets the remaining selection constraints was not available; this choice is among the closest and supplies 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-cost option that also meets the remaining selection constraints was not available; this choice is among the closest and supplies 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 200 mg

California Gold Nutrition
<p>200 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>
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>
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. 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
  3. Current Evidence on Common Dietary Supplements for Sleep Quality.
    Esquivel MK; Ghosn B · American journal of lifestyle medicine · 2025
    Narrative reviewSleep Support forTheanine
  4. 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
  5. 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 participantsSleep Support Brain Health Cognitive Support forTheanine
  6. 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
  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 trialStress Relief Brain Health forTheanine
  8. 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
  9. 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
  10. Effect of Combined Ingestion of L-Theanine and L-Arginine for Short-Term Psychological Stress in Young Adults: A Randomized Placebo-Controlled Study.
    Furushima D; Sugiyama I; Nomura Y; Unno K; Yamada H · Journal of nutritional science and vitaminology · 2023
    Randomized trial120 participantsStress Relief forTheanine
  11. 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
  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 participantsMental Focus Cognitive Support forTheanine
  13. L-theanine improves neurophysiological measures of attention in a dose-dependent manner: a double-blind, placebo-controlled, crossover study.
    Dassanayake TL; Kahathuduwa CN; Weerasinghe VS · Nutritional neuroscience · 2022
    Randomized trial27 participantsMental Focus forTheanine
  14. 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 participantsMental Focus Cognitive Support forTheanine
  15. 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 participantsMental Focus Productivity Boost 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 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
  20. 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
  21. 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
  22. 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
  23. 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
  24. 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
  25. 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
  26. 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