Product Image

L-Theanine 200 mg

Metabolic Maintenance
4.8
★ ★ ★ ★ ★
(296 ratings)
Theanine 200 mg
Product Image
Score82
A branded 200 mg Suntheanine serving provides strong source confidence and focused relaxation. The premium cost is the main drawback.
How scoring works
Quantity:120 Capsule(s) • (120 servings)
Goals:
Stress Relief
Mood Support
Mental Focus
Productivity Boost
Brain Health
Cognitive Support
Sleep Support

Score 82

A branded 200 mg Suntheanine serving provides strong source confidence and focused relaxation. The premium cost is the main drawback.
How scoring works
$70.00($0.58 per serving)
Pure Formulas
$ 70.00
iHerb
$ 70.00
iHerb
$ 70.00
Report prices

Analysis

Branded Suntheanine supplies a well-defined 200 mg L-theanine amount in a focused capsule. The branded source adds useful identity and quality confidence compared with generic options.

The product is well suited to calm focus, acute stress, and relaxation before bed. Its single pathway does not directly support alertness, memory, circadian timing, or broader mood regulation.

One capsule per serving and a large supply are convenient for sustained use. The premium serving cost is much higher than several equally dosed generic alternatives.

Who is it for
  • Adults who prioritize branded theanine
  • People seeking a substantial one-capsule amount
  • Users focused on calm rather than stimulation
Best for
  • Quality-focused theanine use
  • Stress relief
  • Calm attention

Pros

  • Branded Suntheanine source
  • Substantial 200 mg amount
  • One capsule per serving
  • Large 120-serving supply

Cons

  • High serving cost
  • Single-pathway formula
  • No alertness or memory ingredient

Nutrient quality

96 Highest impact

Branded Suntheanine provides a clearly identified L-theanine source. The L-theanine amount is well aligned with common calming and focus use.

.

Ingredient transparency

83 Highest impact

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

.

Customer satisfaction

64 Moderate impact

The supplied aggregate rating is strong, although no specific comments are included. The moderate rating count provides a useful aggregate signal.

.

Value for money

81 Highest impact

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

.
Report analysis

Goals

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

L-theanine at 200 mg directly supports calm attention without acting as a sedative. Human evidence supports reduced stress responses and improved relaxation in some users.

The branded Suntheanine source adds useful identity and quality transparency. 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
Highest effect
A- Goal FitA+ Strength of SupportD+ CoverageA+ Formula Quality

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

The 200 mg amount is well aligned with commonly used supplemental dosing. A single-ingredient design makes the dose easy to assess.

Study evidence
Theanine Supportive 12 studies
Mental Focus
Mental Focus
Impact
Highest effect
B+ Goal FitA+ Strength of SupportD+ CoverageA+ Formula Quality
Theanine · 200 mg

L-theanine at 200 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 well aligned with commonly studied use and is fully disclosed. The branded Suntheanine source adds useful identity and purity assurance.

Study evidence
Theanine Supportive 19 studies
Productivity Boost
Productivity Boost
Impact
Highest effect
B+ Goal FitA+ Strength of SupportD+ CoverageA Formula Quality
Theanine · 200 mg

Suntheanine supplies a well-characterized L-theanine form at a useful amount for calm attention. Clear disclosure and branded sourcing strengthen confidence in active quality.

Used alone, L-theanine is better suited to reducing tension than producing a pronounced productivity lift. The single-ingredient design is focused but does not provide stimulation or broader mental-energy support.

Study evidence
Theanine Supportive 5 studies
Brain Health
Brain Health
Impact
Highest effect
B Goal FitA+ Strength of SupportD+ CoverageA+ Formula Quality

Suntheanine provides targeted support for calm focus and mental resilience without a stimulant. Its role is useful but narrow and does not directly address memory or brain-cell structure.

The branded 200 mg amount is effective and easy to verify. High-purity sourcing strengthens confidence compared with generic theanine products.

Study evidence
Theanine Supportive 17 studies
Cognitive Support
Cognitive Support
Impact
Highest effect
B Goal FitA+ Strength of SupportD+ CoverageA+ Formula Quality
Theanine · 200 mg

Suntheanine provides targeted support for calm focus and mental resilience without a stimulant. Its role is useful but narrow and does not directly address memory or brain-cell structure.

The branded 200 mg amount is effective and easy to verify. High-purity sourcing strengthens confidence compared with generic theanine products.

Study evidence
Theanine Supportive 25 studies
Sleep Support
Sleep Support
Impact
Highest effect
B Goal FitA+ Strength of SupportC- CoverageA Formula Quality
Theanine · 200 mg

Suntheanine provides a branded L-theanine source at a meaningful amount for mental relaxation before bed. Clear disclosure and strong source quality improve confidence in the active.

L-theanine does not directly set circadian timing and may be more helpful when racing thoughts or stress delay sleep. The single-active design is focused but covers only one sleep pathway.

Study evidence
Theanine Supportive 8 studies

Ingredients

IngredientAmount per serving
Suntheanine
200 mg
Gluten Free Adults 18–50 Dairy Free
Report overview
Theanine · 200 mg OverallScore96
A+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyB+ Value

Suntheanine provides a branded, high-purity L-theanine source at an effective dose. Clear individual disclosure makes the active amount easy to verify. Cost efficiency remains competitive despite the premium branded ingredient.

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 ingredient profile remains focused on theanine and offers a practical alternative to the original formula.</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 ingredient profile remains focused on theanine and offers a practical alternative to the original formula.</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 ingredient profile remains focused on theanine and offers a practical alternative to the original formula.</p>
85 Budget

Double Strength L-Theanine 200 mg

NOW
<p>A lower serving cost comes with 200 mg of clearly stated l-theanine. The ingredient profile remains focused on theanine and offers a practical alternative to 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. The ingredient profile remains focused on theanine and offers a practical alternative to 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. The ingredient profile remains focused on theanine and offers a practical alternative to 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. The ingredient profile remains focused on theanine and offers a practical alternative to 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 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. 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