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L-Theanine

NOW
4.7
★ ★ ★ ★ ★
(740 ratings)
Theanine 285 mg
Product Image
Score82
A flexible, high-value liquid with a strong theanine serving that may be more relaxing than some daytime users want.
How scoring works
Quantity:1 Liquid(s) • (93 servings)
Goals:
Stress Relief
Mental Focus
Productivity Boost
Cognitive Support
Sleep Support
Brain Health
Mood Support

Score 82

A flexible, high-value liquid with a strong theanine serving that may be more relaxing than some daytime users want.
How scoring works
$12.60($0.13 per serving)
iHerb
$ 22.03
Vitacost
$ 23.15
Daily Vita
$ 20.80
Daily Vita
$ 12.60
Pure Formulas
$ 21.76
Report prices

Analysis

The liquid supplies a substantial L-theanine amount and allows more serving flexibility than a fixed capsule. It fits stress-related tension and calm-focus routines.

The full serving is relatively high and may feel sedating for sensitive users. No branded source or purity standard is stated.

The large number of servings offers strong value, but careful measurement matters with a concentrated liquid. Starting below a full serving may improve tolerance.

Who is it for
  • Adults who prefer liquid supplements
  • Users wanting adjustable theanine intake
  • People seeking strong relaxation support
Best for
  • Flexible dosing
  • Stress-related tension
  • Evening relaxation

Pros

  • Substantial theanine amount
  • Flexible liquid format
  • Excellent cost efficiency
  • Single active ingredient

Cons

  • Amount may be overly relaxing
  • Generic source
  • No purity standard stated
  • Small liquid servings require careful measurement

Warnings

  • The full serving may cause drowsiness before driving or demanding tasks
  • Sedatives and alcohol may compound the relaxing effect
  • Blood-pressure medicines may increase the chance of lightheadedness when combined with theanine

Nutrient quality

84 Highest impact

L-theanine is suitable, but the source lacks branded purity verification. The stated amount is meaningful but higher than many users need for calm focus.

.

Ingredient transparency

81 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

68 High impact

The supplied aggregate satisfaction signal is favorable. A large amount of feedback makes that aggregate signal reasonably stable, but no narrative evidence was provided.

.

Value for money

95 Highest impact

A substantial active amount and many servings support strong value. The liquid delivers a meaningful amount at favorable serving-level cost.

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Report analysis

Goals

Stress Relief
Stress Relief
Impact
Highest effect
A Goal FitA- Strength of SupportC CoverageA+ Formula Quality
Theanine · 285 mg

L-theanine directly supports a calmer mental state without relying on sedation. The clearly disclosed amount provides strong single-pathway support for acute tension.

The generic source lacks added purity assurance, and measuring a small fraction of a teaspoon may reduce dosing consistency. The higher amount may feel sedating for sensitive users despite the ingredient’s usual relaxed-alertness profile.

Study evidence
Theanine Supportive 16 studies
Mental Focus
Mental Focus
Impact
Highest effect
B Goal FitA+ Strength of SupportC- CoverageA+ Formula Quality
Theanine · 285 mg

L-theanine can support relaxed attention and may be useful when stress interferes with concentration. The 285 mg amount is substantial, though the strongest focus evidence often involves pairing theanine with caffeine.

The single active is fully disclosed and avoids formula clutter. Its calming pathway will not provide the immediate alertness of a stimulant.

Study evidence
Theanine Supportive 19 studies
Productivity Boost
Productivity Boost
Impact
Highest effect
B+ Goal FitA- Strength of SupportC CoverageA+ Formula Quality
Theanine · 285 mg

L-theanine may support calm concentration and reduce tension that interferes with work. Evidence is strongest with caffeine, while the liquid does not create alertness on its own.

The serving provides a high, clearly disclosed amount in a flexible liquid format. Some users may find the higher amount more relaxing than productive, making careful measurement important.

Study evidence
Theanine Supportive 5 studies
Cognitive Support
Cognitive Support
Impact
High effect
B Goal FitB+ Strength of SupportD+ CoverageA- Formula Quality
Theanine · 285 mg

L-theanine directly supports calm focus and reduced mental tension without relying on stimulation. Human evidence supports relaxation and attention benefits, especially when theanine is paired with caffeine.

The 285 mg amount is meaningful but somewhat above the common focus-oriented range. The exact amount is clear, although the generic source lacks purity and stereoisomer verification. The relatively high theanine amount may feel sedating for some users, especially before tasks that require maximum alertness.

Study evidence
Theanine Supportive 25 studies
Sleep Support
Sleep Support
Impact
High effect
C+ Goal FitB Strength of SupportC- CoverageA Formula Quality
Theanine · 285 mg

The 285 mg L-theanine amount may help quiet mental tension before bed, but it exceeds the supplied preferred range. Evidence supports relaxation more clearly than direct improvements in sleep duration or circadian timing.

The liquid clearly discloses one active, though no branded source or purity verification is identified. The small measured serving requires care, and the higher amount may feel overly sedating for some users.

Study evidence
Theanine Supportive 8 studies
Brain Health
Brain Health
Impact
High effect
C+ Goal FitB- Strength of SupportD CoverageA Formula Quality

L-theanine may support calm attention and mental composure, but it does not provide broad structural or neuroprotective support. Its usefulness is therefore focused rather than comprehensive.

The 285 mg amount is fully disclosed but sits above the preferred range for some users. The liquid may require careful measurement and can feel mildly sedating in sensitive users.

Study evidence
Theanine Supportive 17 studies
Mood Support
Mood Support
Impact
High effect
C Goal FitB+ Strength of SupportD CoverageB- Formula Quality

L-theanine may promote calm and reduce stress without functioning as a broad mood treatment. The 285 mg amount is clearly disclosed and fits commonly studied use.

Evidence is more consistent for acute relaxation and attention under stress than for lasting mood stabilization. The single active is focused but leaves neurotransmitter precursor and stress-adaptation pathways uncovered.

Study evidence
Theanine Supportive 12 studies

Ingredients

IngredientAmount per serving
L-Theanine
285 mg
Gluten Free Adults 18–50 Vegan Dairy Free Vegetarian
Report overview
Theanine · 285 mg OverallScore84
B+ Active Ingredient Quality & BioavailabilityB Dose, Safety & Label TransparencyA+ Value

The liquid provides a clearly disclosed L-theanine amount but uses a generic source without added purity evidence. Its dose is above the preferred range and may feel more sedating for some users. Cost efficiency is excellent, while the small measured serving may require careful dosing.

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-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>
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>
83 Budget

L-Theanine 100 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 100 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 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