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L-Theanine 100 mg

The Vitamin Shoppe
4.8
★ ★ ★ ★ ★
(130 ratings)
Theanine 100 mg
Product Image
Score83
A simple, affordable starting-dose theanine capsule with limited source assurance but good everyday usability.
How scoring works
Quantity:60 Capsule(s) • (60 servings)
Goals:
Sleep Support
Stress Relief
Brain Health
Mental Focus
Productivity Boost
Cognitive Support
Mood Support

Score 83

A simple, affordable starting-dose theanine capsule with limited source assurance but good everyday usability.
How scoring works

Also available as

2 options
200.00mg • 120 Capsule(s) servings Theanine 200 mg • 120 Capsule(s) • 120 servings $44.99 ($0.37 per serving) 200.00mg • 60 Capsule(s) servings 200.00mg • 60 Capsule(s) • 60 servings
$19.99($0.33 per serving)
iHerb
$ 19.99
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Analysis

The capsule supplies a sensible starting amount of L-theanine. It fits daytime calm, situational stress, and gentler pre-sleep use.

No branded source or purity specification is provided. The single ingredient also does not cover memory, alertness, or sleep maintenance.

Competitive cost makes it a practical first theanine product. Users needing stronger relaxation may prefer a larger amount.

Who is it for
  • New theanine users
  • Adults seeking mild calm focus
  • People wanting a simple capsule
Best for
  • Starting-dose stress support
  • Daytime calm
  • Light evening relaxation

Pros

  • Preferred starting amount
  • One-capsule serving
  • Single active ingredient
  • Competitive value

Cons

  • Generic source
  • No purity standard
  • Limited pathway coverage
  • May be too mild for some users

Warnings

  • L-theanine may cause drowsiness
  • Sedatives and alcohol may compound relaxation
  • Blood-pressure medicines may increase lightheadedness

Nutrient quality

90 Highest impact

L-theanine is appropriate, but no branded source or purity standard is stated. The active amount is useful as a starting serving for mild support.

.

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

66 High impact

The supplied aggregate satisfaction signal is favorable. Limited feedback volume and absent narrative evidence leave the experience less certain.

.

Value for money

88 Highest impact

The useful amount and simple formula reasonably support the price. Serving-level value is competitive for a dedicated capsule.

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Report analysis

Goals

Sleep Support
Sleep Support
Impact
Highest effect
B+ Goal FitA+ Strength of SupportC+ CoverageA+ Formula Quality
Theanine · 100 mg

The 100 mg L-theanine amount supports relaxation and may ease the transition into sleep when stress or a racing mind is the main barrier. It does not directly regulate circadian timing or act as a strong sedative.

The active L-isomer and exact amount are clearly identified in a simple capsule. No branded source, purity standard, or second sleep pathway is disclosed.

Study evidence
Theanine Supportive 8 studies
Stress Relief
Stress Relief
Impact
Highest effect
A Goal FitA- Strength of SupportC CoverageA+ Formula Quality
Theanine · 100 mg

L-theanine directly supports relaxed alertness and may help acute mental tension without acting as a sedative. The clearly disclosed 100 mg amount reaches a commonly used starting range.

Human evidence is useful for short-term calm, though the single active does not address cortisol regulation or nutrient resilience. The focused capsule avoids token additions and keeps the formula easy to assess.

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

L-theanine is directly relevant to calm focus and may support attention without sedation. The disclosed amount is well aligned with common cognitive use.

The active L-theanine form and individual amount are clear, but no branded purity standard is given. The formula mainly targets calm attention through alpha-wave and inhibitory signaling.

Study evidence
Theanine Supportive 17 studies
Mental Focus
Mental Focus
Impact
High effect
B Goal FitB Strength of SupportD+ CoverageA+ Formula Quality
Theanine · 100 mg

L-theanine may support calm attention by reducing distracting tension without acting as a strong stimulant. Its focus benefit is useful but narrower than a multi-pathway nootropic.

The 100 mg amount is fully disclosed and sits in the preferred range. Generic sourcing without a purity standard limits ingredient-quality confidence.

Study evidence
Theanine Supportive 19 studies
Productivity Boost
Productivity Boost
Impact
High effect
B- Goal FitB+ Strength of SupportD+ CoverageA Formula Quality
Theanine · 100 mg

L-theanine at 100 mg provides a useful lower-end amount for calm attention. The active is clearly identified, although no branded source or purity standard is stated.

The formula is clean and focused but does not provide acute energy or stress-fatigue adaptation. Human performance evidence is strongest when L-theanine is paired with caffeine, making this better suited to calm than stimulation.

Study evidence
Theanine Supportive 5 studies
Cognitive Support
Cognitive Support
Impact
High effect
B- Goal FitB+ Strength of SupportD- CoverageA+ Formula Quality
Theanine · 100 mg

L-theanine may support calm attention and reduce stress-related distraction without acting as a sedative for most people. The 100 mg amount is clearly disclosed.

Evidence is more consistent for relaxation and attention under stress than for memory improvement, and the effect may be stronger when paired with caffeine. The narrow formula does not address circulation, acetylcholine, or long-term neuroprotection.

Study evidence
Theanine Supportive 25 studies
Mood Support
Mood Support
Impact
High effect
C Goal FitB+ Strength of SupportD- CoverageA+ Formula Quality

L-theanine at 100 mg may reduce tension and support a calmer emotional state without strong sedation. Human evidence is more consistent for short-term relaxation and stress responses than for broad mood improvement.

The amount is useful but sits at the lower end of commonly studied use. The single-active design is transparent but covers only one narrow pathway.

Study evidence
Theanine Supportive 12 studies

Ingredients

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

The 100 mg serving falls in the preferred range for calm focus. The label confirms the active L-isomer but gives no branded-source or purity standard. The normalized cost falls in the competitive range.

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. Its disclosed ingredient profile aligns more closely with focused theanine use than 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. Its disclosed ingredient profile aligns more closely with focused theanine use than 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 200 mg

California Gold Nutrition
<p>200 mg of clearly stated L-theanine is paired with favorable serving-level value in the supplied data. Its disclosed ingredient profile aligns more closely with focused theanine use than 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. Its disclosed ingredient profile aligns more closely with focused theanine use than 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