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L-Theanine 100 mg

California Gold Nutrition
4.7
★ ★ ★ ★ ★
(25117 ratings)
Theanine 100 mg
Product Image
Score87
A well-priced branded theanine capsule with flexible 100 mg dosing, though a larger intake requires two capsules.
How scoring works
Quantity:30 Capsule(s) • (30 servings)
Goals:
Mental Focus
Sleep Support
Productivity Boost
Stress Relief
Brain Health
Cognitive Support
Mood Support

Score 87

A well-priced branded theanine capsule with flexible 100 mg dosing, though a larger intake requires two capsules.
How scoring works

Also available as

1 option
60 servings Theanine 100 mg • 60 Capsule(s) • 60 servings $9.43 ($0.15 per serving)
$5.30($0.17 per serving)
iHerb
$ 5.30
Amazon
$ 9.99
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Analysis

AlphaWave identifies a branded L-theanine source at 100 mg per capsule. The moderate amount offers more flexibility than a fixed high-dose product and can suit daytime use.

One capsule may be enough for users who prefer a lighter effect, while two are needed for a 200 mg intake. The focused formula makes that adjustment straightforward.

Value is a notable strength, particularly for a named theanine source. It best fits users who want flexible dosing and do not mind a smaller package or occasional two-capsule serving.

Who is it for
  • Adults seeking a moderate theanine amount
  • Users who value branded sourcing and dose flexibility
Best for
  • Daytime calm-focus support
  • Starting with a lower theanine serving

Pros

  • Uses branded AlphaWave L-theanine
  • Provides flexible 100 mg increments
  • Offers strong value for a named source

Cons

  • A 200 mg intake requires two capsules
  • The 30-serving bottle is relatively small
  • Inactive ingredients are not included in the supplied details

Warnings

  • L-theanine may cause drowsiness, especially when two capsules are combined with alcohol, sedatives, or sleep aids.
  • L-theanine may add to the effects of antihypertensive medicine in people prone to low blood pressure.
  • Assess personal response before using it when sustained alertness is required.

Nutrient quality

94 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

73 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

93 Highest impact

An effective dose and accessible cost support strong value. The focused formula avoids paying for unrelated additions.

.
Report analysis

Goals

Mental Focus
Mental Focus
Impact
Highest effect
B+ Goal FitA+ Strength of SupportC- CoverageA+ Formula Quality
Theanine · 100 mg

Branded L-theanine provides a well-dosed route to calm attention and may reduce distraction from tension. Its focus effect is generally stronger when paired with caffeine than when used alone.

The exact amount and branded active form provide excellent transparency and quality. The single-ingredient design is clean, though it does not address alertness, mental energy, or stress adaptation through separate pathways.

Study evidence
Theanine Supportive 19 studies
Sleep Support
Sleep Support
Impact
Highest effect
B Goal FitA Strength of SupportC+ CoverageA+ Formula Quality
Theanine · 100 mg

A clearly disclosed branded L-theanine dose may help quiet mental tension that delays sleep. Its evidence for relaxation is useful, though sleep-specific results are less direct than those for melatonin.

The single active is well formed, appropriately dosed, and free from conflicting stimulants. Its narrow focus supports relaxation but does not address circadian timing or mineral-related sleep needs.

Study evidence
Theanine Supportive 8 studies
Productivity Boost
Productivity Boost
Impact
Highest effect
B+ Goal FitA Strength of SupportC- CoverageA+ Formula Quality
Theanine · 100 mg

AlphaWave L-theanine may support calm attention and reduce stress-related distraction without acting as a stimulant. Human evidence is useful for relaxation and attention, with the clearest performance benefits often seen when it is paired with caffeine.

The branded active form and exact amount are fully disclosed at a commonly used serving. The single ingredient provides strong depth for calm focus but does not add alertness, energy metabolism, or adaptogenic support.

Study evidence
Theanine Supportive 5 studies
Stress Relief
Stress Relief
Impact
Highest effect
B+ Goal FitA- Strength of SupportC CoverageA Formula Quality
Theanine · 100 mg

L-theanine is a targeted calming amino acid that may reduce tension without strong sedation. Human evidence supports acute relaxation and improved attention under stress, though individual response varies.

The branded AlphaWave form and 100 mg amount are transparent and practical. A single active keeps the product focused, but it does not provide adaptogen or mineral support.

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

AlphaWave L-theanine may support calm, focused alertness without stimulation. Its evidence is relevant to attention and relaxed cognition rather than broad neuroprotection.

The 100 mg amount sits in a commonly useful range, and the branded source improves quality confidence. The focused formula covers one pathway with good practical depth.

Study evidence
Theanine Supportive 17 studies
Cognitive Support
Cognitive Support
Impact
Highest effect
B Goal FitA+ Strength of SupportD+ CoverageA- Formula Quality
Theanine · 100 mg

Branded L-theanine may promote relaxed attention without acting as a stimulant. Its evidence is strongest for calm focus and stress-related performance, not memory or broad long-term cognitive improvement.

The 100 mg amount is clearly disclosed and fits common use, while AlphaWave provides a defined branded source. A single-active formula offers useful depth but no neurotransmitter precursor, circulation, membrane, or energy support.

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

Branded L-theanine offers a targeted way to support calm alertness during stress. Its evidence is stronger for relaxation and focus than for broad, lasting mood change.

The amount is clearly disclosed and falls within the commonly effective range. AlphaWave identifies a quality active source, while the single-ingredient design keeps the formula focused but narrow.

Study evidence
Theanine Supportive 12 studies

Ingredients

IngredientAmount per serving
AlphaWave (L-Theanine)
 100 mg
Gluten Free Adults 18–50 Dairy Free
Report overview
Theanine (L-Theanine) · 100 mg OverallScore96
A+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyB+ Value

AlphaWave L-theanine provides a clearly disclosed amount in a well-supported active form. The dose sits in the commonly effective range for calm focus and relaxation. Its branded source and competitive value make it a well-aligned choice for this collection.

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, providing a larger theanine amount for users who need more pronounced support than the original. 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, providing a larger theanine amount for users who need more pronounced support than the original. 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, providing a larger theanine amount for users who need more pronounced support than the original. Vitamin B6 is not necessary for theanine support, and the serving cost exceeds basic generic options.</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>
83 Budget

L-Theanine 100 mg

California Gold Nutrition
<p>A moderate L-theanine amount provides a flexible starting point at a lower serving cost than the original. No branded source or purity marker is supplied, and the amount is modest.</p>
85 Value

L-Theanine 200 mg

California Gold Nutrition
<p>A substantial L-theanine amount provides focused calming support, providing a lower-cost option with similar or greater ingredient utility than the original. No branded source or purity marker is supplied.</p>
82 Value

Theanine 100 mg

Jarrow Formulas
<p>A moderate L-theanine amount provides a simple option for lighter calm-focus support, providing a lower-cost option with similar or greater ingredient utility than the original. 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, providing a lower-cost option with similar or greater ingredient utility than the original. 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