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TheanineUP Focused Energy

California Gold Nutrition
4.6
★ ★ ★ ★ ★
(2063 ratings)
Theanine 100 mg
Caffeine 100 mg
Green Tea 100 mg
Product Image
Score83
A clear, well-valued caffeine-theanine focus capsule, with timing and total stimulant exposure as the key trade-offs.
How scoring works
Quantity:60 Capsule(s) • (60 servings)
Goals:
Productivity Boost
Energy
Mental Focus
Cognitive Support
Fitness
Brain Health
Weight Loss
Metabolism Boost
Mood Support
Stress Relief

Score 83

A clear, well-valued caffeine-theanine focus capsule, with timing and total stimulant exposure as the key trade-offs.
How scoring works
$11.45($0.19 per serving)
iHerb
$ 11.45
Amazon
$ 14.81
Report prices

Analysis

A 100 mg caffeine amount provides moderate stimulation, matched by 100 mg of theanine to soften the experience for some users. The pairing is well aligned with focus, energy, and productivity.

Cocoa and matcha add small amounts of additional plant compounds. Their natural caffeine contribution is not separately stated, so the true stimulant total may be slightly above the declared caffeine ingredient.

The one-capsule serving is convenient and economical. Sleep support is a poor fit for the formula unless it is taken well before bedtime.

Who is it for
  • Adults seeking moderate focused energy
  • Caffeine users who value added theanine
  • People wanting a simple one-capsule stimulant
Best for
  • Mental focus
  • Daytime energy
  • Task productivity

Pros

  • Balanced caffeine and theanine amounts
  • Convenient one-capsule serving
  • Favorable serving value

Cons

  • Not appropriate for sleep support
  • Botanical caffeine contribution is unclear
  • Does not provide broad metabolic or weight-management support

Warnings

  • Caffeine may cause anxiety, palpitations, or sleep disruption
  • Count coffee, tea, and other stimulant products toward total caffeine intake
  • Avoid taking near bedtime or before activities requiring a calm heart rate

Nutrient quality

84 Highest impact

Balanced caffeine and theanine doses create a coherent focus formula. Caffeine-related tolerability and conflict with sleep use are the main limitations.

.

Ingredient transparency

85 Highest impact

Active names and doses are clearly disclosed. Non-active ingredients and complete usage directions remain missing.

.

Customer satisfaction

67 High impact

The supplied average rating is positive. No specific review comments were supplied, so repeated negative experiences cannot be assessed.

.

Value for money

93 Highest impact

Effective main doses and low serving cost create strong value. The main trade-off is suitability for caffeine-sensitive users.

.
Report analysis

Goals

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

Caffeine and L-theanine form a well-matched pair for alertness with a calmer attentional profile. Both are supplied at useful and clearly stated amounts.

Cocoa and matcha add modest complementary plant compounds without obscuring the core formula. The caffeine 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
Energy
Energy
Impact
Highest effect
A+ Goal FitA+ Strength of SupportB+ CoverageA Formula Quality
Caffeine · 100 mg

Caffeine provides moderate acute alertness, while L-theanine can smooth the subjective stimulant response and support focused attention. Cocoa and matcha add a modest botanical layer without hiding any active amounts.

The caffeine and L-theanine pairing is well balanced and strongly aligned with focused energy rather than physical endurance. Caffeine can still cause sleep disruption, anxiety, or a rapid heartbeat in sensitive users, especially when combined with other caffeine sources.

Study evidence
Caffeine Supportive 68 studies
Theanine Not classified

No linked studies yet.

Mental Focus
Mental Focus
Impact
Highest effect
A+ Goal FitA Strength of SupportB+ CoverageA Formula Quality
Theanine · 100 mgCaffeine · 100 mg

Equal amounts of caffeine and L-theanine create a well-matched calm-alertness pairing for acute focus. Cocoa and matcha may add mild sensory and polyphenol support without dominating the formula.

Each ingredient amount is clearly disclosed, though the caffeine delivery is immediate rather than extended. The stimulant content may still cause sleep disruption or jitteriness in sensitive users, especially when combined with other caffeine sources.

Study evidence
Caffeine Supportive 128 studies
Theanine Supportive 19 studies
Cognitive Support
Cognitive Support
Impact
Highest effect
A Goal FitA- Strength of SupportB- CoverageA- Formula Quality
Green Tea · 100 mgTheanine · 100 mg

L-theanine and caffeine form a well-matched combination for alertness with a calmer subjective feel. Their clearly disclosed amounts are well aligned with short-term attention support.

Cocoa and matcha add possible antioxidant support, but their active compounds are not standardized. The 100 mg caffeine amount may cause sleep disruption, anxiety, or palpitations in stimulant-sensitive users.

Study evidence
Green Tea Supportive 32 studies
Theanine Supportive 25 studies
Fitness
Fitness
Impact
High effect
B+ Goal FitB+ Strength of SupportB- CoverageB+ Formula Quality
Caffeine · 100 mg

Caffeine supports alertness and training focus, while L-theanine may make the stimulant effect feel smoother. Both are provided at 100 mg, a moderate and balanced pairing.

Coffee fruit identifies the caffeine source, but caffeine standardization and release profile are not specified. Cocoa and matcha add related botanicals without clearly stated active-marker contributions.

Study evidence
Caffeine Supportive 255 studies
Brain Health
Brain Health
Impact
High effect
B+ Goal FitA- Strength of SupportB- CoverageB Formula Quality

L-theanine and caffeine provide a logical pairing for alertness with a calmer subjective feel. Human evidence supports the combination for attention more clearly than for long-term brain health.

Both core actives are disclosed at meaningful amounts, while cocoa and matcha add less defined support. The caffeine load may cause jitteriness, rapid heartbeat, or sleep disruption in sensitive users and should be counted with other caffeine sources.

Study evidence
Theanine Supportive 17 studies

Ingredients

IngredientAmount per serving
L-Theanine
100 mg
Caffeine (Coffee Fruit Extract)
 100 mg
Cocoa, Powder
100 mg
Matcha Green Tea, Powder
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 is well aligned with relaxation and focused-attention use. Caffeine provides a balancing stimulant effect, while cocoa and matcha make the formula less suitable for someone seeking theanine alone. The generic source lacks added purity or branded-form assurance, though the amount delivered offers competitive value.

View ingredientView products
Caffeine (Coffee Fruit Extract) · 100 mg OverallScore76
D- Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyA+ Value

The clearly stated caffeine amount falls within the preferred range for focused energy with a moderate stimulant load. Coffee fruit extract provides a named natural source, but no caffeine standardization or controlled-release feature is disclosed. Exact doses are shown for the accompanying ingredients, and the low cost per serving supports strong economic value.

View ingredientView products
Green Tea · 100 mg OverallScore24
F Active Ingredient Quality & BioavailabilityD- Dose, Safety & Label TransparencyF Value

The matcha is an unstandardized powder, so its EGCG strength and related value cannot be verified. No delivery technology or absorption-supporting cofactor is included for the green tea compounds. The disclosed 100 mg caffeine dose may be too stimulating for caffeine-sensitive users or those combining it with other stimulants.

View ingredientView products
Loading alternative details
84 Performance

Smart Caffeine with L-Theanine

NS Natural Stacks
Twice as much theanine as caffeine offers a more calming balance while retaining a moderate green-coffee stimulant dose. The two-ingredient formula is easier to assess, although it omits the original matcha and cocoa.
83 Performance

Pure Energy

Swanson
Caffeine and a higher theanine amount are joined by rhodiola, adding stress and fatigue support to focused energy. Rhodiola standardization is only partly described, so its extract potency is not fully clear.
81 Performance

Matcha

Green Foods
Measured catechins, mild tea caffeine, and a small amount of theanine provide a gentler whole-food matcha option. Theanine is much lower and EGCG is not quantified, so the effect is likely milder and less predictable.
85 Budget

L-Theanine 100 mg

NOW
A simple theanine and decaffeinated green-tea formula supports calm attention with excellent serving value and no stimulant burden. It will not provide the same immediate energy, and the green-tea catechins are not standardized.
74 Budget

Hydroxycut Hardcore Elite

MuscleTech Performance Series
Caffeine, green coffee, and theanine provide low-cost energy and focus support. The aggressive stimulant profile, especially yohimbe, carries much greater anxiety, cardiovascular, and sleep trade-offs.
84 Budget

L-Theanine & Caffeine

SR Sports Research
A two-to-one theanine-to-green-coffee caffeine ratio provides calm alertness with clear amounts and similar serving economics. It lacks matcha and cocoa, but its simpler label gives stronger ingredient clarity.
82 Value

Elite

Eu Natural
A clear two-to-one theanine-to-caffeine formula provides practical calm focus with favorable value. The caffeine source is unspecified, but both active amounts are plainly stated and the formula avoids unnecessary complexity.
59 Value

Super HD

Cellucor
Caffeine and a branded green-tea phytosome provide inexpensive stimulant and green-tea coverage. A hidden thermogenic blend prevents a full safety and potency assessment, making it a lower-confidence value choice.
66 Value

Green Tea Fat Burner

Applied Nutrition
Concentrated green-tea extract and moderate caffeine offer a larger supply and reasonable value for energy and metabolism goals. Two vaguely named blends limit transparency, and the formula lacks theanine to temper stimulation.
Report alternatives

Sources

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

  1. 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
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  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 pooledMental Focus Brain Health Cognitive Support forTheanine
  10. 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
  11. 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
  12. 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
  13. 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
  14. 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 participantsProductivity Boost forCaffeine
  15. 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
  16. 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
  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 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 forTheanine
  19. 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 trialBrain Health Stress Relief forTheanine
  20. 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
  21. 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
  22. Safety and efficacy of cognitive training plus epigallocatechin-3-gallate in young adults with Down's syndrome (TESDAD): a double-blind, randomised, placebo-controlled, phase 2 trial.
    de la Torre R; de Sola S; Hernandez G; Farré M; Pujol J; Rodriguez J; Espadaler JM; Langohr K; Cuenca-Royo A; Principe A; Xicota L; Janel N; Catuara-Solarz S; Sanchez-Benavides G; Bléhaut H; Dueñas-Espín I; Del Hoyo L; Benejam B; Blanco-Hinojo L; Videla S; Fitó M; Delabar JM; Dierssen M; TESDAD study group · The Lancet. Neurology · 2017
    Randomized trial87 participantsCognitive Support forGreen Tea
  23. Association between tea consumption and risk of cognitive disorders: A dose-response meta-analysis of observational studies.
    Liu X; Du X; Han G; Gao W · Oncotarget · 2018
    Meta-analysis48,435 participants17 studies pooledCognitive Support forGreen Tea
  24. Investigating the Impact of Tea Consumption on Cognitive Function and Exploring Tea-Genetic Interactions in Older Adults Aged 65-105 Years: Findings from the 2002-2018 CLHLS Data.
    Yu L; Yang M; Ye KX; Li C; Zou M; Wang J; Yuan X; Zheng D; Sun C; Zhang Y; Feng Q; Maier AB; Sun L; Feng L; Wang Y; Chen H; Zeng Y · The journal of prevention of Alzheimer's disease · 2024
    Cohort study76,270 participantsCognitive Support forGreen Tea
  25. Consumption of green tea, but not black tea or coffee, is associated with reduced risk of cognitive decline.
    Noguchi-Shinohara M; Yuki S; Dohmoto C; Ikeda Y; Samuraki M; Iwasa K; Yokogawa M; Asai K; Komai K; Nakamura H; Yamada M · PloS one · 2014
    Cohort study490 participantsCognitive Support forGreen Tea
  26. Green Tea Consumption and the Risk of Incident Dementia in Elderly Japanese: The Ohsaki Cohort 2006 Study.
    Tomata Y; Sugiyama K; Kaiho Y; Honkura K; Watanabe T; Zhang S; Sugawara Y; Tsuji I · The American journal of geriatric psychiatry : official journal of the American Association for Geriatric Psychiatry · 2018
    Cohort study13,645 participantsCognitive Support forGreen Tea
  27. 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
  28. 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
  29. 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 participantsEnergy forCaffeine
  30. 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
  31. 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
  32. 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
  33. 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
  34. 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
  35. 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
  36. 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
  37. 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
  38. 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
  39. 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
  40. Effects of caffeine on mood and performance: a study of realistic consumption.
    Brice CF; Smith AP · Psychopharmacology · 2003
    Clinical trial24 participantsMental Focus forCaffeine
  41. 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
  42. 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
  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. 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
  45. 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
  46. 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 participantsMetabolism Boost forCaffeine
  47. 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
  48. 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
  49. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials.
    Liu K; Zhou R; Wang B; Chen K; Shi LY; Zhu JD; Mi MT · The American journal of clinical nutrition · 2013
    Meta-analysis1,133 participants17 studies pooledMetabolism Boost forGreen Tea
  50. Green tea extract ingestion, fat oxidation, and glucose tolerance in healthy humans.
    Venables MC; Hulston CJ; Cox HR; Jeukendrup AE · The American journal of clinical nutrition · 2008
    Randomized trial23 participantsMetabolism Boost forGreen Tea
  51. Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans.
    Dulloo AG; Duret C; Rohrer D; Girardier L; Mensi N; Fathi M; Chantre P; Vandermander J · The American journal of clinical nutrition · 1999
    Randomized trial10 participantsMetabolism Boost forGreen Tea
  52. A 60-Day Green Tea Extract Supplementation Counteracts the Dysfunction of Adipose Tissue in Overweight Post-Menopausal and Class I Obese Women.
    Rondanelli M; Gasparri C; Perna S; Petrangolini G; Allegrini P; Fazia T; Bernardinelli L; Cavioni A; Mansueto F; Oberto L; Patelli Z; Tartara A; Riva A · Nutrients · 2022
    Randomized trial28 participantsMetabolism Boost forGreen Tea
  53. Epigallocatechin gallate alleviates non-alcoholic fatty liver disease through the inhibition of the expression and activity of Dipeptide kinase 4.
    Yang M; Yan R; Sha R; Wang X; Zhou S; Li B; Zheng Q; Cao Y · Clinical nutrition (Edinburgh, Scotland) · 2024
    Randomized trialMetabolism Boost forGreen Tea
  54. 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
  55. 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
  56. 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 pooledMood Support forTheanine
  57. 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
  58. 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
  59. Effects of caffeine on alertness.
    Zwyghuizen-Doorenbos A; Roehrs TA; Lipschutz L; Timms V; Roth T · Psychopharmacology · 1990
    Randomized trial24 participantsProductivity Boost forCaffeine
  60. 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
  61. Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training. Sea-Air-Land.
    Lieberman HR; Tharion WJ; Shukitt-Hale B; Speckman KL; Tulley R · Psychopharmacology · 2003
    Randomized trial68 participantsProductivity Boost forCaffeine
  62. A review of caffeine's effects on cognitive, physical and occupational performance.
    McLellan TM; Caldwell JA; Lieberman HR · Neuroscience and biobehavioral reviews · 2017
    Narrative reviewProductivity Boost forCaffeine
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    Wang R; Wang W; Meng L; Hao G; Gu G · Frontiers in nutrition · 2026
    Meta-analysis7 studies pooledProductivity Boost forCaffeine
  64. 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
  65. 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
  66. Changes in caffeine intake and long-term weight change in men and women.
    Lopez-Garcia E; van Dam RM; Rajpathak S; Willett WC; Manson JE; Hu FB · The American journal of clinical nutrition · 2006
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  67. Does caffeine ingestion before a short-term sprint interval training promote body fat loss?
    Ferreira GA; Felippe LC; Bertuzzi R; Bishop DJ; Ramos IS; De-Oliveira FR; Lima-Silva AE · Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas · 2020
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  68. Eight Weeks of Sprint Interval Training With Adding Caffeine Ingestion Leads to Greater Improvements in Health-Related Physiological Parameters in Obese Male Adults.
    Zhiang J; Song Q · Physiological research · 2026
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  69. Caffeine treatment prevented from weight regain after calorie shifting diet induced weight loss.
    Davoodi SH; Hajimiresmaiel SJ; Ajami M; Mohseni-Bandpei A; Ayatollahi SA; Dowlatshahi K; Javedan G; Pazoki-Toroudi H · Iranian journal of pharmaceutical research : IJPR · 2014
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    Tabrizi R; Saneei P; Lankarani KB; Akbari M; Kolahdooz F; Esmaillzadeh A; Nadi-Ravandi S; Mazoochi M; Asemi Z · Critical reviews in food science and nutrition · 2020
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  71. A green tea extract high in catechins reduces body fat and cardiovascular risks in humans.
    Nagao T; Hase T; Tokimitsu I · Obesity (Silver Spring, Md.) · 2007
    Randomized trial240 participantsWeight Loss forGreen Tea
  72. Green tea beverages enriched with catechins with a galloyl moiety reduce body fat in moderately obese adults: a randomized double-blind placebo-controlled trial.
    Kobayashi M; Kawano T; Ukawa Y; Sagesaka YM; Fukuhara I · Food & function · 2016
    Randomized trial126 participantsWeight Loss forGreen Tea
  73. Green tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adults.
    Maki KC; Reeves MS; Farmer M; Yasunaga K; Matsuo N; Katsuragi Y; Komikado M; Tokimitsu I; Wilder D; Jones F; Blumberg JB; Cartwright Y · The Journal of nutrition · 2009
    Randomized trial132 participantsWeight Loss forGreen Tea
  74. Effect of Decaffeinated Green Tea Polyphenols on Body Fat and Precocious Puberty in Obese Girls: A Randomized Controlled Trial.
    Xie L; Tang Q; Yao D; Gu Q; Zheng H; Wang X; Yu Z; Shen X · Frontiers in endocrinology · 2022
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  75. Effectiveness of green tea on weight reduction in obese Thais: A randomized, controlled trial.
    Auvichayapat P; Prapochanung M; Tunkamnerdthai O; Sripanidkulchai BO; Auvichayapat N; Thinkhamrop B; Kunhasura S; Wongpratoom S; Sinawat S; Hongprapas P · Physiology & behavior · 2008
    Randomized trial60 participantsWeight Loss forGreen Tea