Product Image

Suntheanine L-Theanine 100 mg

Natural Factors Stress-Relax
4.7
★ ★ ★ ★ ★
(3954 ratings)
Theanine 200 mg
Product Image
Score81
Branded Suntheanine and a practical full-serving amount support quality, but the name-to-serving dose mismatch deserves attention.
How scoring works
Quantity:120 Tablet(s) • (60 servings)
Goals:
Sleep Support
Mood Support
Stress Relief
Mental Focus
Cognitive Support
Brain Health
Productivity Boost

Score 81

Branded Suntheanine and a practical full-serving amount support quality, but the name-to-serving dose mismatch deserves attention.
How scoring works

Also available as

1 option
60 servings Theanine 200 mg • 60 Tablet(s) • 30 servings $18.87 ($0.62 per serving)
$35.67($0.59 per serving)
iHerb
$ 35.67
Amazon
$ 35.67
Vitacost
$ 35.67
Report prices

Analysis

Suntheanine identifies a branded L-theanine source, and the ingredient panel supplies 200 mg per full serving. That amount is practical for calm attention or evening relaxation without adding a complex blend.

The product name highlights 100 mg while the listed serving provides 200 mg, so users should check how many tablets make one serving. Added carbohydrate and calories are minor but make the format less streamlined than a basic capsule.

Ingredient quality is the main reason to choose it, not economy. It best fits people who value a defined theanine source and do not mind the tablet format or moderate serving value.

Who is it for
  • Adults seeking calm focus or evening relaxation
  • Users who value a branded L-theanine source
Best for
  • A substantial theanine serving
  • People comfortable checking tablet-based serving directions

Pros

  • Uses branded Suntheanine L-theanine
  • Provides 200 mg per listed full serving
  • Keeps the active formula focused

Cons

  • The product name and full-serving amount may be confusing
  • Contains added carbohydrate and calories
  • Serving value is only moderate

Warnings

  • L-theanine can cause drowsiness, especially when combined with alcohol, sedatives, or sleep aids.
  • The full serving supplies more than the amount emphasized in the product name, so the tablet count should be checked before use.
  • L-theanine may add to the effects of antihypertensive medicine in people prone to low blood pressure.

Nutrient quality

91 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 the full tablet base remain unavailable.

.

Customer satisfaction

71 High impact

The supplied average is strong and backed by very large volume. No review themes were provided, so consistency and purpose-specific experience cannot be assessed.

.

Value for money

72 High impact

An effective dose provides good core value. A low-value supporting component reduces efficiency.

.
Report analysis

Goals

Sleep Support
Sleep Support
Impact
Highest effect
B+ Goal FitA+ Strength of SupportC CoverageA+ Formula Quality
Theanine · 200 mg

The chewable supplies an effective, precisely disclosed relaxation amount. It provides 200 mg of branded Suntheanine L-theanine for a defined sleep-related pathway.

L-theanine may help users settle but does not directly regulate circadian timing or sleep maintenance. The focused formula may suit users whose main barrier is pre-sleep mental tension.

Study evidence
Theanine Supportive 8 studies
Mood Support
Mood Support
Impact
Highest effect
B+ Goal FitA+ Strength of SupportC+ CoverageA+ Formula Quality

Branded L-theanine at 200 mg may support a calmer mood and reduce stress-related tension without strong sedation. Human evidence is better for relaxation and stress response than for persistent low mood.

The Suntheanine source and exact amount are clearly disclosed in a simple gummy. The single active provides focused calm support but does not address serotonin precursors, adaptogenic resilience, or inflammatory pathways.

Study evidence
Theanine Supportive 12 studies
Stress Relief
Stress Relief
Impact
Highest effect
A- Goal FitA+ Strength of SupportC CoverageA+ Formula Quality
Theanine · 200 mg

Branded L-theanine at a material dose is well aligned with calm focus and acute relaxation. Human evidence supports reduced stress responses without the heavy sedation associated with sleep-focused ingredients.

Suntheanine provides a standardized, clearly disclosed source with strong formulation quality. The single-active design is narrow, but it delivers substantial depth without stimulants or unnecessary herbs.

Study evidence
Theanine Supportive 16 studies
Mental Focus
Mental Focus
Impact
Highest effect
B+ Goal FitA+ Strength of SupportC- CoverageA Formula Quality
Theanine · 200 mg

Branded L-theanine provides a focused way to support calm attention without a stimulant. Human evidence supports relaxation and selected attention outcomes, with stronger focus effects often seen when it is paired with caffeine.

The full serving amount is clearly disclosed and lies within a commonly used range. Suntheanine sourcing adds purity confidence, while the chewable format contributes a small carbohydrate load.

Study evidence
Theanine Supportive 19 studies
Cognitive Support
Cognitive Support
Impact
Highest effect
B Goal FitA+ Strength of SupportC- CoverageA+ Formula Quality
Theanine · 200 mg

Suntheanine provides a meaningful L-theanine amount that may support calm attention during stress. The effect is focused on relaxed concentration rather than memory formation, circulation, or brain energy.

The branded form and active amount are clearly disclosed in a streamlined chewable. The 200 mg amount may feel too calming or cause mild drowsiness in sensitive users.

Study evidence
Theanine Supportive 25 studies
Brain Health
Brain Health
Impact
Highest effect
B Goal FitA+ Strength of SupportC CoverageA Formula Quality

Branded Suntheanine may support calm attention and focus without acting as a stimulant. The disclosed serving reaches a well-supported amount.

The chewable formula is simple and its active source is easy to assess. A single calming pathway offers limited support for memory, neuronal structure, or long-term brain resilience.

Study evidence
Theanine Supportive 17 studies
Productivity Boost
Productivity Boost
Impact
High effect
B Goal FitA+ Strength of SupportD+ CoverageB+ Formula Quality
Theanine · 200 mg

Branded Suntheanine may support calm focus and reduce distraction without strong sedation. It does not provide stimulant energy or broader memory support.

The theanine amount is well aligned with common targeted use and uses a well-defined branded material. The gummy adds a moderate carbohydrate load without improving the active effect.

Study evidence
Theanine Supportive 5 studies

Ingredients

IngredientAmount per serving
Calories
15 Calorie(s)
Total Carbohydrates
4 Gram(s)
Suntheanine L-Theanine
200 mg
Gluten Free Adults 18–50 Vegan Dairy Free Vegetarian
Report overview
Theanine · 200 mg OverallScore96
A+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyB+ Value

Suntheanine supplies a high-purity branded L-theanine source at an effective amount. Clear disclosure makes the serving easy to assess and use consistently. The larger package maintains competitive cost efficiency.

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, matching the original's focused role with stronger ingredient identity or dose flexibility. 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, matching the original's focused role with stronger ingredient identity or dose flexibility. 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, matching the original's focused role with stronger ingredient identity or dose flexibility. Vitamin B6 is not necessary for theanine support, and the serving cost exceeds basic generic options.</p>
85 Budget

L-Theanine 200 mg

California Gold Nutrition
<p>A substantial L-theanine amount provides focused calming support at a lower serving cost than the original. No branded source or purity marker is supplied.</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>
87 Value

L-Theanine 100 mg

California Gold Nutrition
<p>Branded AlphaWave L-theanine provides a clearly identified amount for moderate calm-focus support, preserving the original's calm-focus role at a lower serving cost. The amount is lower than the common single-serving amount used by many other options.</p>
82 Value

Theanine 100 mg

Jarrow Formulas
<p>A moderate L-theanine amount provides a simple option for lighter calm-focus support, preserving the original's calm-focus role at a lower serving cost. 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, preserving the original's calm-focus role at a lower serving cost. 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