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Theanine

Thorne
4.7
★ ★ ★ ★ ★
(1615 ratings)
Theanine 200 mg
Product Image
Score81
A high-quality 200 mg Suntheanine capsule with excellent convenience, but its premium cost sharply limits value.
How scoring works
Quantity:90 Capsule(s) • (90 servings)
Goals:
Sleep Support
Mental Focus
Stress Relief
Cognitive Support
Brain Health
Productivity Boost
Mood Support

Score 81

A high-quality 200 mg Suntheanine capsule with excellent convenience, but its premium cost sharply limits value.
How scoring works
$68.00($0.75 per serving)
iHerb
$ 68.00
Vitacost
$ 68.00
Pure Formulas
$ 68.00
Amazon
$ 68.00
Vitacost
$ 68.03
Report prices

Analysis

Suntheanine identifies the L-theanine source, and 200 mg per capsule is a practical amount for common daytime or evening use. The focused active formula is easy to understand.

One capsule supplies the full serving, which supports consistent use and avoids a large pill count. No additional actives complicate dose assessment, although the supplied details do not show inactive ingredients.

The main limitation is value rather than dose or active quality. It best fits users who specifically prefer this brand and are comfortable paying more for a straightforward Suntheanine capsule.

Who is it for
  • Adults who prefer branded Suntheanine
  • Users seeking a one-capsule calm-focus routine
Best for
  • A clearly defined 200 mg theanine serving
  • Brand-loyal users who accept premium pricing

Pros

  • Uses branded Suntheanine L-theanine
  • Provides 200 mg in one capsule
  • Keeps the active formula focused

Cons

  • Serving cost is high
  • Less economical than comparable branded options
  • Inactive ingredients are not included in the supplied details

Warnings

  • L-theanine may cause drowsiness, particularly with alcohol, sedatives, or sleep aids.
  • L-theanine may add to the effects of antihypertensive medicine in people prone to low blood pressure.
  • Assess the 200 mg capsule before using it when sustained alertness is required.

Nutrient quality

97 Highest impact

The branded source and clearly stated amount support reliable theanine use. The focused formula avoids dilution from unrelated actives.

.

Ingredient transparency

86 Highest impact

Active amounts are clear without a hidden blend. Complete directions and inactive ingredients remain unavailable.

.

Customer satisfaction

72 High impact

The supplied average is very strong and backed by very large volume. No review themes were provided, so consistency and purpose-specific experience cannot be assessed.

.

Value for money

64 Moderate impact

The source quality provides some value, but the serving cost is premium. The focused formula avoids paying for unrelated additions.

.
Report analysis

Goals

Sleep Support
Sleep Support
Impact
Highest effect
B+ Goal FitA+ Strength of SupportC+ CoverageA+ Formula Quality
Theanine · 200 mg

L-theanine supports relaxation without acting as a sedative and may help people settle before sleep. Sleep evidence is useful but less direct and consistent than for melatonin.

The branded Suntheanine source is supplied at a substantial 200 mg amount and is fully disclosed. The streamlined formula covers relaxation well but does not address circadian timing or mineral support.

Study evidence
Theanine Supportive 8 studies
Mental Focus
Mental Focus
Impact
Highest effect
B+ Goal FitA+ Strength of SupportC- CoverageA+ Formula Quality
Theanine · 200 mg

Branded Suntheanine at 200 mg may support calm attention with well-defined active quality. The amount is fully disclosed and sits within a commonly used range.

A single active keeps the formula clear and avoids unnecessary ingredients. Without caffeine or another alertness ingredient, its benefit is more likely to feel calming than activating.

Study evidence
Theanine Supportive 19 studies
Stress Relief
Stress Relief
Impact
Highest effect
A- Goal FitA+ Strength of SupportC- CoverageA+ Formula Quality
Theanine · 200 mg

Suntheanine provides 200 mg of branded high-purity L-theanine for calm attention and reduced mental tension. The dose is effective, fully disclosed, and well aligned with the selected goal.

The single active does not add adaptogenic or mineral pathways, but its focused mechanism receives strong depth. The streamlined capsule avoids stimulants, sedatives, and unrelated nutrients.

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

Branded L-theanine directly supports calm attention and may reduce stress-related distraction without strong sedation. The substantial serving is well aligned with human research on relaxed focus.

Suntheanine provides useful quality assurance and the exact amount is clearly disclosed. Coverage remains limited to one attention-related pathway rather than memory, circulation, or brain-energy support.

Study evidence
Theanine Supportive 25 studies
Brain Health
Brain Health
Impact
Highest effect
B+ Goal FitA+ Strength of SupportC- CoverageA+ Formula Quality

Suntheanine may support calm, focused alertness without acting as a stimulant. Its evidence is useful for attention and stress-related focus rather than broad neuroprotection.

The 200 mg amount is well aligned with common effective use, and the branded source strengthens purity confidence. The focused capsule covers one cognitive pathway with strong practical depth.

Study evidence
Theanine Supportive 17 studies
Productivity Boost
Productivity Boost
Impact
Highest effect
B Goal FitA+ Strength of SupportC+ CoverageB+ Formula Quality
Theanine · 200 mg

Branded Suntheanine supplies a well-studied L-theanine amount that may support calm attention and reduce stress-related distraction. The dose, purity, and disclosure make it a credible targeted focus aid.

Used alone, L-theanine is not a stimulant and may feel subtle for users seeking stronger alertness. Pairing it with caffeine is better studied for acute attention, but that complementary pathway is absent here.

Study evidence
Theanine Supportive 5 studies
Mood Support
Mood Support
Impact
Highest effect
B Goal FitA+ Strength of SupportD+ CoverageA+ Formula Quality

Branded L-theanine provides well-supported acute relaxation without relying on sedation. It is better suited to stress-related calm and focus than to broad, long-term mood regulation.

The clearly disclosed amount sits at the upper end of the commonly effective range and uses a standardized branded source. The focused capsule avoids unrelated actives, though it covers only one mood-support pathway.

Study evidence
Theanine Supportive 12 studies

Ingredients

IngredientAmount per serving
Suntheanine (L-Theanine)
 200 mg
Gluten Free Adults 18–50
Report overview
Theanine (L-Theanine) · 200 mg OverallScore90
A+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyD+ Value

Suntheanine provides a branded high-purity L-theanine source at an effective amount. The active dose is clearly disclosed and the capsule stays focused on theanine. Premium sourcing supports quality, but the cost per active amount is also premium.

View ingredientView products
Loading alternative details
87 Performance

L-Theanine 200 mg Double Strength

Swanson
<p>Branded Suntheanine provides a substantial, focused amount without unrelated active ingredients, matching the original's focused role with stronger ingredient identity or dose flexibility. It does not include melatonin or other bedtime ingredients, so its role is broader than sleep alone.</p>
85 Performance

L-Theanine 150 mg

Solgar
<p>Branded Suntheanine provides a moderate amount that supports calm focus without pushing the dose high, matching the original's focused role with stronger ingredient identity or dose flexibility. The smaller amount may feel less pronounced for users who prefer a stronger single serving.</p>
83 Performance

L-Theanine 200 mg

Country Life
<p>Branded Suntheanine supplies a substantial amount, while vitamin B6 is fully disclosed as a secondary ingredient, matching the original's focused role with stronger ingredient identity or dose flexibility. Vitamin B6 is not necessary for theanine support, and the serving cost exceeds basic generic options.</p>
85 Budget

L-Theanine 200 mg

California Gold Nutrition
<p>A substantial L-theanine amount provides focused calming support at a lower serving cost than the original. No branded source or purity marker is supplied.</p>
85 Budget

Double Strength L-Theanine 200 mg

NOW
<p>A substantial L-theanine amount provides focused support with a modest inositol addition at a lower serving cost than the original. Generic sourcing provides less ingredient assurance, and the inositol amount adds little.</p>
84 Budget

L-Theanine 200 mg

Advance Physician Formulas
<p>A substantial L-theanine amount provides simple calm-focus support at a lower serving cost than the original. No branded source or purity marker is supplied.</p>
87 Value

L-Theanine 100 mg

California Gold Nutrition
<p>Branded AlphaWave L-theanine provides a clearly identified amount for moderate calm-focus support, preserving the original's calm-focus role at a lower serving cost. The amount is lower than the common single-serving amount used by many other options.</p>
82 Value

Theanine 100 mg

Jarrow Formulas
<p>A moderate L-theanine amount provides a simple option for lighter calm-focus support, preserving the original's calm-focus role at a lower serving cost. No branded source or purity marker is supplied.</p>
85 Value

L-Theanine 100 mg

NOW
<p>A practical L-theanine amount pairs with decaffeinated green tea, preserving the original's calm-focus role at a lower serving cost. The green-tea catechins are not standardized, and the theanine source is not branded.</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 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
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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
  21. 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
  22. 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
  23. 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
  24. 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
  25. 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