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L-Theanine 100 mg

California Gold Nutrition
4.7
★ ★ ★ ★ ★
(25106 ratings)
Theanine 100 mg
Product Image
Score83
A practical 100 mg capsule combines a cautious amount with excellent everyday value. Its lower dose, generic source, and narrow pathway coverage are the trade-offs.
How scoring works
Quantity:60 Capsule(s) • (60 servings)
Goals:
Stress Relief
Mood Support
Brain Health
Cognitive Support
Mental Focus
Sleep Support
Productivity Boost

Score 83

A practical 100 mg capsule combines a cautious amount with excellent everyday value. Its lower dose, generic source, and narrow pathway coverage are the trade-offs.
How scoring works

Also available as

1 option
200.00mg • 60 Capsule(s) servings Theanine 200 mg • 60 Capsule(s) • 60 servings $10.06 ($0.16 per serving)
$9.43($0.15 per serving)
Amazon
$ 10.84
iHerb
$ 9.43
Report prices

Analysis

A 100 mg L-theanine capsule offers a practical lower-range amount for calm attention and relaxation. The simple single-active formula supports easy dose assessment and routine use.

It best fits mild situational stress or users who want a cautious starting amount. The lower amount and single pathway provide limited support for productivity, memory, broad mood, or sleep maintenance.

One capsule per serving, extensive aggregate feedback, and strong value are important strengths. Generic sourcing and absent inactive-ingredient details leave some quality uncertainty.

Who is it for
  • Adults starting with a lower theanine amount
  • People seeking mild situational calm
  • Users who prioritize value
Best for
  • Mild stress relief
  • Calm focus
  • Adjustable theanine routines

Pros

  • Useful 100 mg amount
  • One capsule per serving
  • Excellent active efficiency
  • Extensive aggregate feedback

Cons

  • Lower-range amount
  • Generic source
  • Inactive ingredients were not supplied
  • No complementary pathway

Nutrient quality

90 Highest impact

L-theanine is a defined amino acid, although no branded source or purity marker is supplied. The L-theanine amount is practical for moderate daily support.

.

Ingredient transparency

81 Highest impact

Every supplied active ingredient has a specific amount. No proprietary blend hides a meaningful active dose.

.

Customer satisfaction

68 High impact

The supplied aggregate rating is strong, although no specific comments are included. The large rating count makes the aggregate result relatively stable.

.

Value for money

91 Highest impact

Formula quality provides strong support for the product positioning. Dose-adjusted serving value appears strong, while the formula avoids obvious low-value padding.

.
Report analysis

Goals

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

L-theanine at 100 mg directly supports calm attention without acting as a sedative. Human evidence supports reduced stress responses and improved relaxation in some users.

The individual amount is clearly disclosed in a simple capsule. A single active provides focused nervous-system support but does not address cortisol or foundational mineral pathways.

Study evidence
Theanine Supportive 16 studies
Mood Support
Mood Support
Impact
High effect
B Goal FitB+ Strength of SupportD CoverageA Formula Quality

L-theanine provides a focused calming active that may reduce stress without strong sedation. The formula does not address serotonin precursors, adaptogens, or mineral pathways.

The 100 mg amount is useful but at the lower end of common targeted use. A single-ingredient design makes the dose easy to assess.

Study evidence
Theanine Supportive 12 studies
Brain Health
Brain Health
Impact
High effect
B- Goal FitB+ Strength of SupportD CoverageA+ Formula Quality

L-theanine may support calm focus and attention without acting as a stimulant. Its role is useful but narrow, with little direct support for memory or neuronal structure.

The 100 mg amount reaches an effective lower-range serving and is clearly disclosed. Generic sourcing leaves purity less certain than a branded standardized form.

Study evidence
Theanine Supportive 17 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 focus and attention without acting as a stimulant. Its role is useful but narrow, with little direct support for memory or neuronal structure.

The 100 mg amount reaches an effective lower-range serving and is clearly disclosed. Generic sourcing leaves purity less certain than a branded standardized form.

Study evidence
Theanine Supportive 25 studies
Mental Focus
Mental Focus
Impact
High effect
B- Goal FitB Strength of SupportD- CoverageA+ Formula Quality
Theanine · 100 mg

L-theanine at 100 mg may promote calm attention without acting as a stimulant. Evidence is more consistent for relaxation and for pairing with caffeine than for large attention gains when used alone.

The amount is useful but sits at the lower end of commonly studied use. The single-active design is transparent, though no branded source or purity standard is given.

Study evidence
Theanine Supportive 19 studies
Sleep Support
Sleep Support
Impact
High effect
B- Goal FitB Strength of SupportC- CoverageA- Formula Quality
Theanine · 100 mg

The clearly disclosed L-theanine amount may help quiet mental tension without acting as a sedative. The capsule is simple and easy to fit into a bedtime routine.

The amount sits at the low end of the useful range, and no branded source or purity testing is provided. A single active supports relaxation but does not address circadian timing or physical mineral needs.

Study evidence
Theanine Supportive 8 studies
Productivity Boost
Productivity Boost
Impact
High effect
C+ Goal FitB Strength of SupportD CoverageA+ Formula Quality
Theanine · 100 mg

L-theanine provides focused calm-attention support at a useful starting amount. It may help distractible tension without acting as a stimulant.

The single-ingredient formula is transparent and streamlined. No branded source or added purity verification is disclosed.

Study evidence
Theanine Supportive 5 studies

Ingredients

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

The clearly disclosed L-theanine dose sits in the effective range for calm focus support. Its generic source lacks added purity or branded-form assurances. 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-cost option that also meets the remaining selection constraints was not available; this choice is among the closest and supplies 200 mg of clearly stated l-theanine. Its disclosed ingredient profile aligns more closely with focused theanine use than the original formula.</p>
85 Budget

L-Theanine 200 mg

California Gold Nutrition
<p>A lower-cost option that also meets the remaining selection constraints was not available; this choice is among the closest and supplies 200 mg of clearly stated l-theanine. 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>
82 Value

Theanine 100 mg

Jarrow Formulas
<p>100 mg of clearly stated L-theanine is paired with favorable serving-level value in the supplied data. The ingredient profile remains focused on theanine and offers a practical alternative to the original formula.</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