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L-Theanine 200 mg

Protocol For Life Balance
4.8
★ ★ ★ ★ ★
(751 ratings)
Theanine 200 mg
Product Image
Score80
A sensible 200 mg theanine capsule with a small inositol extra, held back by generic sourcing and unremarkable value.
How scoring works
Quantity:60 Capsule(s) • (60 servings)
Goals:
Stress Relief
Brain Health
Productivity Boost
Sleep Support
Mental Focus
Cognitive Support
Mood Support

Score 80

A sensible 200 mg theanine capsule with a small inositol extra, held back by generic sourcing and unremarkable value.
How scoring works
$23.90($0.39 per serving)
Pure Formulas
$ 27.00
iHerb
$ 27.00
Vitacost
$ 27.00
Amazon
$ 23.90
Report prices

Analysis

L-theanine provides the main functional amount at 200 mg per capsule. The added 100 mg of inositol is modest and is unlikely to be the reason to choose the product.

The formula can suit daytime calm, focused work, or evening relaxation without becoming an extensive blend. Clear active amounts make it easy to understand, but no branded theanine source is named.

Serving value is reasonable rather than exceptional. It best fits users who want a full theanine amount and see the inositol as a minor extra rather than a meaningful second active.

Who is it for
  • Adults seeking calm focus or relaxation
  • Users who do not need a branded theanine source
Best for
  • A practical full theanine serving
  • People who view inositol as a minor addition

Pros

  • Provides 200 mg of clearly disclosed L-theanine
  • Uses a simple two-active formula
  • One capsule supplies the listed serving

Cons

  • The theanine source is not branded
  • The 100 mg inositol amount adds limited practical value
  • Inactive-ingredient details are not supplied

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.
  • Users sensitive to calming supplements should first assess the 200 mg serving when alertness is not required.

Nutrient quality

89 Highest impact

The explicit identity and clearly stated amount support reliable theanine use. The small inositol addition contributes little extra depth.

.

Ingredient transparency

85 Highest impact

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

.

Customer satisfaction

71 High impact

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

.

Value for money

73 High impact

An effective dose provides good core value. A low-value supporting component reduces efficiency.

.
Report analysis

Goals

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

L-theanine provides a strong, focused calm-alertness effect for acute daily stress. The 200 mg amount is well suited to mental tension without relying on a sedative.

Inositol adds a small related mood pathway but is far below a standalone amount. The simple formula is transparent, though the generic theanine lacks a branded purity standard.

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

L-theanine supports calm attention, while inositol may add a mild complementary signaling pathway. The formula is focused on mental composure rather than memory, structural support, or neuroprotection.

Theanine has a fully disclosed amount in a well-supported range. The generic source lacks a purity standard, but the compact combination avoids dilution and conflicting ingredients.

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

L-theanine can support calm concentration when stress or stimulant tension reduces productivity. The 200 mg amount is meaningful, although it does not provide direct alertness on its own.

Inositol is a modest companion with little evidence for an acute productivity effect. The streamlined formula is best suited to calm-focus needs rather than fatigue or low drive.

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

L-theanine provides focused nervous system relaxation that may help users settle before bed. Evidence for direct sleep improvement is moderate, and the product does not address circadian timing.

The 200 mg L-theanine amount is meaningful and fully disclosed. Inositol at 100 mg is far below typical gram-level supplemental use and adds little practical sleep depth.

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

L-theanine is supplied at a preferred amount for calm, non-stimulant attention. Inositol adds a small complementary calming component without obscuring the main active.

The simple formula is transparent and avoids sedatives. It does not provide alertness, neurotransmitter precursors, or broader cognitive support, so its fit is strongest when tension disrupts focus.

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

L-theanine directly supports calm attention and may reduce stress-related distraction. Human evidence supports attention and relaxation effects, although cognitive benefits are often stronger when paired with caffeine.

The 200 mg L-theanine amount sits within a well-supported effective range. The exact L-theanine amount is clear, but the generic source has no branded purity standard.

Study evidence
Theanine Supportive 25 studies
Mood Support
Mood Support
Impact
High effect
C+ Goal FitA Strength of SupportC CoverageA Formula Quality

L-theanine at 200 mg may support a calmer response to short-term stress without strong sedation. Inositol adds a second mood-related ingredient, but its 100 mg amount is far below amounts used for more targeted effects.

The formula is transparent and easy to assess. Its narrow emphasis on acute calm limits support for broader or persistent mood concerns.

Study evidence
Theanine Supportive 12 studies

Ingredients

IngredientAmount per serving
L-Theanine
200 mg
Inositol
100 mg
Gluten Free Adults 18–50 Vegan Dairy Free Vegetarian
Report overview
Theanine · 200 mg OverallScore88
B+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyB+ Value

Clearly identified L-theanine is provided at an effective amount with straightforward disclosure. The generic source lacks a branded purity standard, but the simple capsule avoids a complex blend. Cost efficiency is competitive for a dedicated supplement.

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