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L-Theanine 100 mg

Life Extension
4.7
★ ★ ★ ★ ★
(149 ratings)
Theanine 100 mg
Product Image
Score84
A clean, good-value starting-dose theanine capsule for calm focus, with limited source-quality assurance.
How scoring works
Quantity:60 Capsule(s) • (60 servings)
Goals:
Stress Relief
Mental Focus
Productivity Boost
Cognitive Support
Brain Health
Sleep Support
Mood Support

Score 84

A clean, good-value starting-dose theanine capsule for calm focus, with limited source-quality assurance.
How scoring works
$17.95($0.29 per serving)
Walmart
$ 17.95
Pure Formulas
$ 18.00
Vitacost
$ 18.00
Vitacost
$ 18.00
Report prices

Analysis

The capsule provides a preferred starting amount of L-theanine in one unit. It fits mild situational stress and daytime calm without forcing a high serving.

No branded source or purity standard is disclosed. The single active does not cover memory, alertness, or sleep maintenance.

Competitive cost makes it a useful general entry point. Users can judge their response without interference from companion ingredients.

Who is it for
  • New L-theanine users
  • Adults seeking mild stress support
  • People wanting a single active
Best for
  • Daytime calm
  • Situational stress
  • Simple one-capsule routines

Pros

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

Cons

  • Generic source
  • No purity specification
  • Narrow pathway coverage
  • May be too mild for stronger relaxation needs

Warnings

  • L-theanine may cause drowsiness
  • Sedatives or alcohol may increase relaxation
  • Blood-pressure medicines may contribute to 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

65 High impact

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

.

Value for money

93 Highest impact

The useful amount and clean single-active design support strong value. Serving-level economics are favorable for a dedicated capsule.

.
Report analysis

Goals

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

L-theanine is well aligned with short-term calm and relaxed attention. The stated amount reaches a useful starting range in a simple one-capsule formula.

The formula is focused and fully disclosed, although no branded source or extra purity standard is named. A single active offers less pathway coverage than a complementary stress-support blend.

Study evidence
Theanine Supportive 16 studies
Mental Focus
Mental Focus
Impact
Highest effect
A- Goal FitA- Strength of SupportC CoverageB+ Formula Quality
Theanine · 100 mg

L-theanine at 100 mg may support calm attention without acting as a stimulant. The exact amount is clear and reaches a useful starting dose.

The formula is streamlined and avoids sedating herbs or unrelated vitamins. Its focus effect is likely subtler alone than when paired with caffeine, so it suits people seeking smoother concentration rather than stronger alertness.

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

A clearly disclosed L-theanine dose may support calm attention when stress or tension interferes with focus. It does not provide direct stimulation, so the productivity effect is likely to be subtle when used alone.

The simple formula provides a meaningful starting amount without unnecessary ingredients. No branded source or purity standard is disclosed, which limits confidence in premium ingredient quality.

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

Theanine may support calm attention and reduce stress-related distraction. The disclosed amount reaches a commonly useful level in a focused formula.

Benefits are narrower than those of a broad memory or learning supplement. No stimulant, choline source, or memory-focused botanical extends cognitive coverage.

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

L-theanine at 100 mg can support calm attention and mental resilience without strong sedation. The single-capsule amount is a practical starting dose.

The product is narrow and does not address memory, neuronal energy, or membrane structure. Generic sourcing without a purity or branded-material marker leaves some uncertainty about ingredient quality.

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

L-theanine may promote a calmer mental state that helps some people prepare for sleep. The 100 mg amount is a reasonable starting dose and is clearly supplied in one capsule.

Theanine does not directly regulate circadian timing and is better supported for relaxation than for treating nighttime awakenings. The streamlined formula is easy to assess, although no branded source or purity qualification is provided.

Study evidence
Theanine Supportive 8 studies
Mood Support
Mood Support
Impact
High effect
C Goal FitB Strength of SupportD CoverageA+ Formula Quality

L-theanine provides focused calming support at a useful starting amount. It may help stress-related tension but does not cover the wider biology of persistent mood problems.

The single-ingredient capsule is simple and clearly disclosed. No branded source or added purity standard is identified.

Study evidence
Theanine Supportive 12 studies

Ingredients

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

The formula clearly identifies L-theanine and provides a preferred starting dose in one capsule. No branded source or added purity claim is disclosed, limiting evidence for premium ingredient quality. Cost efficiency is competitive for a straightforward single-ingredient option.

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 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. 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
  4. 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 participantsStress Relief Mental Focus Productivity Boost forTheanine
  5. 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
  6. 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 trialMental Focus Brain Health Productivity Boost forTheanine
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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 participantsCognitive Support 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 participantsCognitive Support Mental Focus forTheanine
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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
  21. 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
  22. 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
  23. 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