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Elite

Eu Natural
4.2
★ ★ ★ ★ ★
(3508 ratings)
Theanine 200 mg
Caffeine 100 mg
Product Image
Score82
A simple, well-balanced caffeine and theanine pair offers strong daytime value. It remains a stimulant product and is unsuitable near bedtime.
How scoring works
Quantity:120 Capsule(s) • (60 servings)
Goals:
Energy
Productivity Boost
Mental Focus
Brain Health
Fitness
Stress Relief
Metabolism Boost
Weight Loss
Mood Support
Cognitive Support

Score 82

A simple, well-balanced caffeine and theanine pair offers strong daytime value. It remains a stimulant product and is unsuitable near bedtime.
How scoring works
$19.99($0.33 per serving)
Vitacost
$ 24.29
Amazon
$ 19.99
Pure Formulas
$ 19.99
iHerb
$ 24.99
Report prices

Analysis

Caffeine at 100 mg provides moderate alertness, while 200 mg L-theanine may smooth tension without removing the stimulant effect. The simple ratio is easy to assess and well aligned with focus and productivity.

The formula offers acute cognitive support rather than memory, structural brain health, or exercise recovery. It is poorly suited to sleep because caffeine directly works against bedtime relaxation.

Sixty servings and a low serving cost support practical daily value. The caffeine form and theanine source quality are not identified.

Who is it for
  • Adults seeking moderate focused energy
  • People who prefer a simple two-active formula
  • Caffeine users wanting more theanine
Best for
  • Mental focus
  • Productivity
  • Daytime energy

Pros

  • Provides 200 mg L-theanine
  • Moderate 100 mg caffeine amount
  • Simple formula
  • Good serving value

Cons

  • Caffeine source is unspecified
  • Theanine purity details are absent
  • No sustained-release feature
  • Not designed for memory or sleep

Warnings

  • Caffeine may cause jitteriness, palpitations, anxiety, or sleep disruption
  • Avoid late-day use
  • Account for coffee, tea, energy drinks, and other caffeine sources

Nutrient quality

89 Highest impact

L-theanine is clearly named, while the caffeine source and form are not specified. Both theanine and caffeine are present at meaningful, balanced amounts.

.

Ingredient transparency

81 Highest impact

Active amounts are stated and no proprietary blend hides a core dose. Missing excipient details and complete use directions leave the supplied label information incomplete.

.

Customer satisfaction

63 Moderate impact

The supplied aggregate satisfaction average provides a broad signal, while the response volume determines how stable it appears. No comment-level evidence is available to assess repeated complaints or confirm intended-use experiences.

.

Value for money

94 Highest impact

Useful active delivery supports favorable serving value. The two-active formula shows no low-value padding.

.
Report analysis

Goals

Energy
Energy
Impact
Highest effect
A+ Goal FitA+ Strength of SupportB+ CoverageA+ Formula Quality
Caffeine · 100 mg

Caffeine and L-theanine form a well-supported pairing for alertness with calmer focus. The 100 mg caffeine and 200 mg L-theanine amounts are both clearly disclosed and well balanced.

The formula targets acute mental energy rather than mitochondrial fuel or long-term fatigue causes. Caffeine can still disrupt sleep or cause jitteriness in sensitive users, especially when taken late in the day.

Study evidence
Caffeine Supportive 68 studies
Theanine Not classified

No linked studies yet.

Productivity Boost
Productivity Boost
Impact
Highest effect
A+ Goal FitA Strength of SupportB+ CoverageA+ Formula Quality
Theanine · 200 mgCaffeine · 100 mg

Caffeine and L-theanine create a well-supported combination for alertness, attention, and calm focus. The moderate stimulant amount is balanced by twice as much theanine, which may reduce jitteriness without removing the productivity benefit.

Both active amounts are fully disclosed, though the caffeine source and theanine purity details are not identified. The 100 mg caffeine serving may still cause jitters or sleep disruption in sensitive users, especially when taken later in the day.

Study evidence
Caffeine Supportive 108 studies
Theanine Supportive 5 studies
Mental Focus
Mental Focus
Impact
Highest effect
A+ Goal FitA Strength of SupportB CoverageA+ Formula Quality
Theanine · 200 mgCaffeine · 100 mg

Caffeine and L-theanine form a well-matched pairing for alert but composed focus. Both ingredients have useful human evidence and are provided at practical amounts.

The simple formula offers strong depth in its chosen alertness pathway. Caffeine may still cause sleep disruption or jitteriness in sensitive users, particularly when taken late or combined with other caffeine.

Study evidence
Caffeine Supportive 128 studies
Theanine Supportive 19 studies
Brain Health
Brain Health
Impact
Highest effect
A- Goal FitA Strength of SupportB CoverageA+ Formula Quality

Caffeine and L-theanine form a well-supported combination for alertness, attention, and smoother focus. The pairing is suited to short-term cognitive performance rather than long-term neuronal structure.

Both amounts are clearly disclosed and use a practical two-to-one theanine-to-caffeine balance. The caffeine can still cause anxiety, rapid heartbeat, or sleep disruption in sensitive users.

Study evidence
Theanine Supportive 17 studies
Fitness
Fitness
Impact
Highest effect
A Goal FitB Strength of SupportC+ CoverageA+ Formula Quality
Caffeine · 100 mg

The 100 mg caffeine amount can provide moderate alertness and may reduce perceived effort during training. Twice as much L-theanine may smooth the stimulant experience and support focused attention.

The pairing is streamlined and transparent, but it does not support muscle repair, hydration, or ATP regeneration. Caffeine may still disrupt sleep or cause jitters in sensitive users, especially when combined with coffee, energy drinks, or other stimulant products.

Study evidence
Caffeine Supportive 255 studies
Stress Relief
Stress Relief
Impact
High effect
B+ Goal FitA- Strength of SupportC+ CoverageB Formula Quality
Theanine · 200 mg

L-theanine at a substantial amount may promote relaxed attention and offset some caffeine-related tension. Caffeine can improve alertness but may work against calm in sensitive users.

Both actives are fully disclosed and meaningfully dosed in a simple formula. The 100 mg caffeine amount may cause jitters or disturb sleep, especially when taken later in the day.

Study evidence
Theanine Supportive 16 studies

Ingredients

IngredientAmount per serving
Caffeine
100 mg
L-Theanine
200 mg
Gluten Free Adults 18–50 Dairy Free
Report overview
Theanine · 200 mg OverallScore88
B+ Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyB+ Value

The simple formula supplies an optimal amount of clearly disclosed L-Theanine. Its generic source lacks branded purity assurance, but cost efficiency is competitive. The accompanying 100 mg of caffeine may support alertness but can cause jitteriness or sleep disruption in sensitive users.

View ingredientView products
Caffeine · 100 mg OverallScore65
F Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyB+ Value

The caffeine dose is clearly disclosed and falls within the moderate target range. The source and form are not identified, so purity and absorption characteristics cannot be judged with confidence. Theanine complements the stimulant profile, and the low serving cost supports good value.

View ingredientView products
Loading alternative details
84 Performance

L-Theanine & Caffeine

SR Sports Research
<p>Two hundred milligrams of theanine with 100 mg PurCaf green-coffee caffeine provides a clear two-to-one calm-focus balance, giving a clearer or more purpose-specific option than the original clear two-to-one pairing of 200 mg theanine and 100 mg caffeine. The softgel oil is not necessary for these water-soluble ingredients, and caffeine timing still matters.</p>
87 Performance

L-Theanine 200 mg Double Strength

Swanson
<p>A focused 200 mg Suntheanine serving offers substantial branded theanine for calm attention and relaxation, giving a clearer or more purpose-specific option than the original clear two-to-one pairing of 200 mg theanine and 100 mg caffeine. It omits caffeine, so users seeking strong immediate energy would need a different approach.</p>
87 Performance

L-Theanine 100 mg

California Gold Nutrition
<p>A clearly disclosed 100 mg AlphaWave L-theanine serving provides branded, focused support for calm attention, giving a clearer or more purpose-specific option than the original clear two-to-one pairing of 200 mg theanine and 100 mg caffeine. The caffeine-free design favors relaxation and sensitivity but will not reproduce stimulant-driven energy.</p>
87 Budget

Caffeine 200 mg

ALLMAX
<p>A clearly disclosed 200 mg anhydrous caffeine dose provides direct short-term energy and focus at a lower serving cost than the original clear two-to-one pairing of 200 mg theanine and 100 mg caffeine. It has no theanine to temper stimulation, so sensitive users may experience jitters or sleep disruption.</p>
85 Budget

L-Theanine 200 mg

California Gold Nutrition
<p>A focused 200 mg L-theanine serving supports calm attention without adding stimulant exposure at a lower serving cost than the original clear two-to-one pairing of 200 mg theanine and 100 mg caffeine. No branded source or purity marker is supplied, and it will not provide the energy effect of caffeine.</p>
81 Budget

Natural Caffeine

BodyTech
<p>A clearly disclosed 200 mg coffee-derived caffeine dose provides simple stimulant support with a named source at a lower serving cost than the original clear two-to-one pairing of 200 mg theanine and 100 mg caffeine. The formula lacks theanine and may cause jitters or sleep disruption in sensitive users.</p>
85 Value

Double Strength L-Theanine 200 mg

NOW
<p>A 200 mg L-theanine amount with 100 mg inositol provides simple calm-focus support at an equal or lower serving cost compared with the original clear two-to-one pairing of 200 mg theanine and 100 mg caffeine. Generic theanine offers less purity assurance than a branded form, and the inositol amount adds little.</p>
82 Value

Caffeine 200 mg

Best Naturals
<p>A clearly disclosed 200 mg anhydrous caffeine serving provides inexpensive, predictable stimulation at an equal or lower serving cost compared with the original clear two-to-one pairing of 200 mg theanine and 100 mg caffeine. It lacks theanine and offers little beyond stimulation, with routine jitter and sleep-disruption concerns.</p>
83 Value

TheanineUP Focused Energy

California Gold Nutrition
<p>An even 100 mg theanine and 100 mg coffee-fruit caffeine pairing supports alert focus, with cocoa and matcha adding mild complementary stimulation at an equal or lower serving cost compared with the original clear two-to-one pairing of 200 mg theanine and 100 mg caffeine. The one-to-one ratio may feel less calming than a two-to-one formula, and caffeine can still disrupt sleep.</p>
Report alternatives

Sources

Published studies used for the product analysis and the top-ranked studies for each ingredient and goal.

  1. Effects of Caffeine Intake on Cognitive Performance Related to Total Sleep Deprivation and Time on Task: A Randomized Cross-Over Double-Blind Study.
    Quiquempoix M; Sauvet F; Erblang M; Van Beers P; Guillard M; Drogou C; Trignol A; Vergez A; Léger D; Chennaoui M; Gomez-Merino D; Rabat A · Nature and science of sleep · 2022
    Randomized trial24 participantsEnergy Productivity Boost forCaffeine
  2. Using coffee to compensate for poor sleep: Impact on vigilance and implications for workplace performance.
    Anderson JR; Hagerdorn PL; Gunstad J; Spitznagel MB · Applied ergonomics · 2018
    Randomized trial69 participantsMental Focus forCaffeine
  3. 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
  4. Caffeine administration at night during extended wakefulness effectively mitigates performance impairment but not subjective assessments of fatigue and sleepiness.
    Paech GM; Banks S; Pajcin M; Grant C; Johnson K; Kamimori GH; Vedova CB · Pharmacology, biochemistry, and behavior · 2017
    Randomized trial24 participantsEnergy forCaffeine
  5. 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 forTheanine
  6. 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 participantsProductivity Boost Mental Focus forTheanine
  7. Effects of Acute Caffeine Ingestion on Cognitive Performance before and after Repeated Small-Sided Games in Professional Soccer Players: A Placebo-Controlled, Randomized Crossover Trial.
    de Almeida RF; de Oliveira M; Furigo IC; Aquino R; Clarke ND; Tallis J; Guimaraes-Ferreira L · Nutrients · 2023
    Randomized trial12 participantsProductivity Boost forCaffeine
  8. No effects of caffeine on cycling to exhaustion and perceptual responses in non-caffeine-restricted subjects.
    Weippert M; Behrens M; Schlegel M; Schröder T; Tillmann M; Rühe N; Römer R; Mau-Möller A; Bruhn S · Journal of the International Society of Sports Nutrition · 2025
    Randomized trial56 participantsEnergy forCaffeine
  9. Physiological and cognitive responses to caffeine during repeated, high-intensity exercise.
    Crowe MJ; Leicht AS; Spinks WL · International journal of sport nutrition and exercise metabolism · 2007
    Randomized trial17 participantsMental Focus forCaffeine
  10. 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
  11. 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
  12. Association of the anxiogenic and alerting effects of caffeine with ADORA2A and ADORA1 polymorphisms and habitual level of caffeine consumption.
    Rogers PJ; Hohoff C; Heatherley SV; Mullings EL; Maxfield PJ; Evershed RP; Deckert J; Nutt DJ · Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2010
    Randomized trial379 participantsProductivity Boost forCaffeine
  13. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features.
    Juliano LM; Griffiths RR · Psychopharmacology · 2005
    Systematic review66 studies pooledEnergy forCaffeine
  14. A double-blind, placebo-controlled study evaluating the effects of caffeine and L-theanine both alone and in combination on cerebral blood flow, cognition and mood.
    Dodd FL; Kennedy DO; Riby LM; Haskell-Ramsay CF · Psychopharmacology · 2016
    Randomized trial24 participantsMental Focus forTheanine
  15. Caffeinated Coffee and Tea Consumption, Genetic Variation and Cognitive Function in the UK Biobank.
    Cornelis MC; Weintraub S; Morris MC · The Journal of nutrition · 2020
    Cross-sectional study445,786 participantsMental Focus forCaffeine
  16. 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
  17. 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
  18. 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 pooledMental Focus Brain Health Cognitive Support forTheanine
  19. Acute effects of caffeine on attention: a comparison of non-consumers and withdrawn consumers.
    Smith AP; Christopher G; Sutherland D · Journal of psychopharmacology (Oxford, England) · 2013
    Randomized trial70 participantsMental Focus forCaffeine
  20. Limited Efficacy of Caffeine and Recovery Costs During and Following 5 Days of Chronic Sleep Restriction.
    Doty TJ; So CJ; Bergman EM; Trach SK; Ratcliffe RH; Yarnell AM; Capaldi VF; Moon JE; Balkin TJ; Quartana PJ · Sleep · 2018
    Clinical trial48 participantsProductivity Boost forCaffeine
  21. Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose.
    Giles GE; Mahoney CR; Brunyé TT; Gardony AL; Taylor HA; Kanarek RB · Pharmacology, biochemistry, and behavior · 2013
    Randomized trial48 participantsEnergy forCaffeine
  22. Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial.
    Wingelaar-Jagt YQ; Bottenheft C; Riedel WJ; Ramaekers JG · Journal of psychopharmacology (Oxford, England) · 2023
    Randomized trial32 participantsMental Focus forCaffeine
  23. Effects of caffeine and glucose, alone and combined, on cognitive performance.
    Adan A; Serra-Grabulosa JM · Human psychopharmacology · 2010
    Randomized trial72 participantsProductivity Boost forCaffeine
  24. 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
  25. Does Single or Combined Caffeine and Taurine Supplementation Improve Athletic and Cognitive Performance without Affecting Fatigue Level in Elite Boxers? A Double-Blind, Placebo-Controlled Study.
    Ozan M; Buzdagli Y; Eyipinar CD; Baygutalp NK; Yüce N; Oget F; Kan E; Baygutalp F · Nutrients · 2022
    Randomized trial20 participantsEnergy forCaffeine
  26. 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 participantsStress Relief Brain Health Cognitive Support forTheanine
  27. The effects of L-theanine, caffeine and their combination on cognition and mood.
    Haskell CF; Kennedy DO; Milne AL; Wesnes KA; Scholey AB · Biological psychology · 2008
    Randomized trialMental Focus forCaffeine
  28. Caffeine reversal of sleep deprivation effects on alertness and mood.
    Penetar D; McCann U; Thorne D; Kamimori G; Galinski C; Sing H; Thomas M; Belenky G · Psychopharmacology · 1995
    Randomized trial50 participantsProductivity Boost forCaffeine
  29. 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
  30. Trait Energy and Fatigue Modify the Effects of Caffeine on Mood, Cognitive and Fine-Motor Task Performance: A Post-Hoc Study.
    Fuller DT; Smith ML; Boolani A · Nutrients · 2021
    Randomized trialEnergy forCaffeine
  31. Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses.
    Yoto A; Motoki M; Murao S; Yokogoshi H · Journal of physiological anthropology · 2013
    Randomized trial14 participantsStress Relief forTheanine
  32. Caffeine and attentional control: improved and impaired performance in healthy older adults and Parkinson's disease according to task demands.
    Sharma K; Fallon SJ; Davis T; Ankrett S; Munro G; Christopher G; Coulthard E · Psychopharmacology · 2022
    Randomized trial68 participantsMental Focus forCaffeine
  33. Effects of Different Sources of Low-Dose Caffeine on Mood/Arousal and Cognitive Performance.
    Irwin C; McCartney D; Grant G; Delang N; Bartrim K; Cox GR; Desbrow B · Perceptual and motor skills · 2023
    Randomized trial22 participantsProductivity Boost forCaffeine
  34. 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
  35. Effect of Caffeine on Golf Performance and Fatigue during a Competitive Tournament.
    Mumford PW; Tribby AC; Poole CN; Dalbo VJ; Scanlan AT; Moon JR; Roberts MD; Young KC · Medicine and science in sports and exercise · 2016
    Randomized trial12 participantsEnergy forCaffeine
  36. 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
  37. The combined effects of L-theanine and caffeine on cognitive performance and mood.
    Owen GN; Parnell H; De Bruin EA; Rycroft JA · Nutritional neuroscience · 2009
    Randomized trial27 participantsMental Focus forCaffeine
  38. Caffeine and Cognitive Functions in Sports: A Systematic Review and Meta-Analysis.
    Lorenzo Calvo J; Fei X; Domínguez R; Pareja-Galeano H · Nutrients · 2021
    Meta-analysis13 studies pooledProductivity Boost forCaffeine
  39. 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 participantsStress Relief Mood Support forTheanine
  40. Effect of three caffeine doses on plasma catecholamines and alertness during prolonged wakefulness.
    Kamimori GH; Penetar DM; Headley DB; Thorne DR; Otterstetter R; Belenky G · European journal of clinical pharmacology · 2001
    Randomized trial50 participantsProductivity Boost forCaffeine
  41. The effect of mouth rinsing with different concentrations of caffeine solutions on reaction time.
    Virdinli SG; Kutlay E; Yuzbasioglu Y; Vollaard NBJ; Rudarli Nalcakan G · Journal of sports sciences · 2022
    Randomized trial45 participantsMental Focus forCaffeine
  42. Caffeine Supplementation and Physical Performance, Muscle Damage and Perception of Fatigue in Soccer Players: A Systematic Review.
    Mielgo-Ayuso J; Calleja-Gonzalez J; Del Coso J; Urdampilleta A; León-Guereño P; Fernández-Lázaro D · Nutrients · 2019
    Systematic review17 participants17 studies pooledEnergy forCaffeine
  43. 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
  44. 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
  45. Cognitive and mood improvements of caffeine in habitual consumers and habitual non-consumers of caffeine.
    Haskell CF; Kennedy DO; Wesnes KA; Scholey AB · Psychopharmacology · 2005
    Randomized trial48 participantsProductivity Boost Energy forCaffeine
  46. Caffeine attenuates scopolamine-induced memory impairment in humans.
    Riedel W; Hogervorst E; Leboux R; Verhey F; van Praag H; Jolles J · Psychopharmacology · 1996
    Randomized trial16 participantsMental Focus forCaffeine
  47. Effect of caffeine intake on fat oxidation rate during exercise: is there a dose-response effect?
    Gutiérrez-Hellín J; Aguilar-Navarro M; Ruiz-Moreno C; Muñoz A; Varillas-Delgado D; Amaro-Gahete FJ; Del Coso J · European journal of nutrition · 2023
    Randomized trial18 participantsEnergy Metabolism Boost forCaffeine
  48. 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
  49. 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 participantsStress Relief Mood Support forTheanine
  50. 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
  51. Caffeine-containing energy drink improves physical performance of elite rugby players during a simulated match.
    Del Coso J; Ramírez JA; Muñoz G; Portillo J; Gonzalez-Millán C; Muñoz V; Barbero-Álvarez JC; Muñoz-Guerra J · Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme · 2016
    Randomized trial26 participantsEnergy forCaffeine
  52. Effect of caffeine ingestion on cycling performance: a systematic review and meta-analysis.
    Wu J; Xu K; Yin M; Ding X; Wang T; Zhang Q; Wu X; Xiao N · Frontiers in nutrition · 2026
    Meta-analysis226 participants20 studies pooledFitness forCaffeine
  53. Effects of Caffeine Intake on Endurance Running Performance and Time to Exhaustion: A Systematic Review and Meta-Analysis.
    Wang Z; Qiu B; Gao J; Del Coso J · Nutrients · 2023
    Meta-analysis254 participants21 studies pooledFitness forCaffeine
  54. Acute Effects of Caffeine Supplementation on Movement Velocity in Resistance Exercise: A Systematic Review and Meta-analysis.
    Raya-González J; Rendo-Urteaga T; Domínguez R; Castillo D; Rodríguez-Fernández A; Grgic J · Sports medicine (Auckland, N.Z.) · 2021
    Meta-analysis12 studies pooledFitness forCaffeine
  55. Sex Differences in the Ergogenic Response of Acute Caffeine Intake on Muscular Strength, Power and Endurance Performance in Resistance-Trained Individuals: A Randomized Controlled Trial.
    Montalvo-Alonso JJ; Ferragut C; Del Val-Manzano M; Valadés D; Roberts J; Pérez-López A · Nutrients · 2024
    Randomized trial76 participantsFitness forCaffeine
  56. Can I Have My Coffee and Drink It? A Systematic Review and Meta-analysis to Determine Whether Habitual Caffeine Consumption Affects the Ergogenic Effect of Caffeine.
    Carvalho A; Marticorena FM; Grecco BH; Barreto G; Saunders B · Sports medicine (Auckland, N.Z.) · 2022
    Meta-analysis60 studies pooledFitness forCaffeine
  57. Performance and alertness effects of caffeine, dextroamphetamine, and modafinil during sleep deprivation.
    Wesensten NJ; Killgore WD; Balkin TJ · Journal of sleep research · 2006
    Randomized trial48 participantsMental Focus forCaffeine
  58. Effects of caffeine on mood and performance: a study of realistic consumption.
    Brice CF; Smith AP · Psychopharmacology · 2003
    Clinical trial24 participantsMental Focus forCaffeine
  59. Effects of caffeine or diphenhydramine on visual vigilance.
    Fine BJ; Kobrick JL; Lieberman HR; Marlowe B; Riley RH; Tharion WJ · Psychopharmacology · 1995
    Randomized trial24 participantsMental Focus forCaffeine
  60. A Randomized Study to Examine the Ability of a Caffeine-Based Energy Drink to Impact Energy Expenditure, Fat Oxidation, and Cognitive Performance.
    Krieger J; Schrautemeier A; Hagele A; Gaige C; Mennemeyer O; Tolbert S; Iannotti J; Kerksick C; Noonan C; Mumford P · Nutrients · 2025
    Randomized trial60 participantsMetabolism Boost forCaffeine
  61. Oolong tea increases metabolic rate and fat oxidation in men.
    Rumpler W; Seale J; Clevidence B; Judd J; Wiley E; Yamamoto S; Komatsu T; Sawaki T; Ishikura Y; Hosoda K · The Journal of nutrition · 2001
    Randomized trial12 participantsMetabolism Boost forCaffeine
  62. Comparison of changes in energy expenditure and body temperatures after caffeine consumption.
    Koot P; Deurenberg P · Annals of nutrition & metabolism · 1995
    Randomized trial12 participantsMetabolism Boost forCaffeine
  63. Caffeine Increases Work Done above Critical Power, but Not Anaerobic Work.
    Silveira R; Andrade-Souza VA; Arcoverde L; Tomazini F; Sansonio A; Bishop DJ; Bertuzzi R; Lima-Silva AE · Medicine and science in sports and exercise · 2018
    Randomized trial9 participantsMetabolism Boost forCaffeine
  64. l-theanine adjunct to sertraline for major depressive disorder: A randomized, double-blind, placebo-controlled clinical trial.
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