Product Image

Nitrosurge Shred Fruit Punch

Jacked Factory JF
4.8
★ ★ ★ ★ ★
(13 ratings)
Theobromine 50 mg
Caffeine 180 mg
Product Image
Score73
A broadly dosed pre-workout with meaningful performance and focus ingredients. Citrulline and beta-alanine are modest for a full pre-workout is the key trade-off alongside a premium serving cost.
How scoring works
Quantity:8 Ounce(s) • (30 servings)
Goals:
Energy
Mental Focus
Metabolism Boost
Productivity Boost
Fitness
Weight Loss

Score 73

A broadly dosed pre-workout with meaningful performance and focus ingredients. Citrulline and beta-alanine are modest for a full pre-workout is the key trade-off alongside a premium serving cost.
How scoring works
$29.99($0.99 per serving)
iHerb
$ 29.99
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Analysis

Moderate caffeine, theobromine, citrulline, theanine, beta-alanine, and one gram of acetyl L-carnitine covers pump, training capacity, and energy in one serving. Theanine and acetyl L-carnitine balance energy with focus support adds a cognitive component, though stimulant effects will drive much of the immediate experience.

The formula fits energy, fitness, muscle, and productivity goals better than broad brain health. Strong dosing may suit experienced pre-workout users but can be excessive for stimulant-sensitive people.

Most important actives have stated amounts, supporting direct comparison. Citrulline and beta-alanine are modest for a full pre-workout remains the main transparency problem, while a premium serving cost weakens practical value.

Who is it for
  • Experienced adults seeking a high-stimulant pre-workout
  • Users wanting pump, training, and focus support together
  • People who can avoid other caffeine sources
Best for
  • Workout energy
  • Training performance
  • Short-term mental focus

Pros

  • Covers several performance pathways
  • Theanine and acetyl L-carnitine balance energy with focus support
  • Discloses the main stimulant amount

Cons

  • Citrulline and beta-alanine are modest for a full pre-workout
  • a premium serving cost
  • Not suited to caffeine-sensitive users

Warnings

  • Caffeine and theobromine create a moderate caffeine can cause jitteriness, rapid heartbeat, anxiety, or sleep disruption, especially with other stimulants.
  • Beta-alanine commonly causes harmless tingling, while the stimulant load may be harder to tolerate.
  • BioPerine can alter exposure to some medicines by changing their absorption or metabolism.

Nutrient quality

78 High impact

Caffeine, acetyl L-carnitine, theanine, and performance actives create a coherent pre-workout. Citrulline and beta-alanine lack full dose depth, while combined stimulants need caution.

.

Ingredient transparency

79 High impact

Every active dose is visible and no hidden blend is present. Complete directions, purity details, and inactive flavor-system ingredients remain unavailable.

.

Customer satisfaction

58 Moderate impact

The supplied aggregate satisfaction signal is favorable and has some support from its response volume. Specific experience details are absent, so complaint patterns and purpose fit cannot be confirmed.

.

Value for money

72 High impact

Relevant pre-workout formula depth supports reasonable value. Incomplete form detail or uneven dosing prevents a stronger comparison.

.
Report analysis

Goals

Energy
Energy
Impact
Highest effect
A+ Goal FitA Strength of SupportA- CoverageA+ Formula Quality
Acetyl L-Carnitine · 1 Gram(s)Caffeine · 180 mg

Caffeine, acetyl-L-carnitine, citrulline, beta-alanine, theobromine, and theanine support alertness, mental drive, and exercise performance. The major actives have strong or credible human evidence for acute energy and stamina.

Every active has a precise amount, and caffeine pairs logically with theanine. Citrulline and beta-alanine are below common full performance doses, but the stimulant and carnitine pathways remain meaningful. Caffeine and theobromine create a combined stimulant load that may cause rapid heartbeat, anxiety, or sleep disruption in sensitive users.

Study evidence
Acetyl L-Carnitine Supportive 19 studies
Caffeine Supportive 68 studies
Citrulline No effect 14 studies
Theanine Not classified

No linked studies yet.

Theobromine Adverse 1 study
Mental Focus
Mental Focus
Impact
Highest effect
A Goal FitA Strength of SupportA- CoverageA- Formula Quality
Acetyl L-Carnitine · 1 Gram(s)Theanine · 90 mgCaffeine · 180 mg

Caffeine, acetyl-L-carnitine, L-theanine, and theobromine provide complementary alertness, mental-energy, and calm-focus support. Their amounts are clearly disclosed and generally substantial.

The pre-workout also includes citrulline and beta-alanine for exercise rather than cognition. A combined 180 mg caffeine dose with theobromine can cause jitteriness, a faster heartbeat, or sleep disruption in stimulant-sensitive users.

Study evidence
Acetyl L-Carnitine Supportive 7 studies
Caffeine Supportive 128 studies
Theanine Supportive 19 studies
Metabolism Boost
Metabolism Boost
Impact
Highest effect
A- Goal FitA- Strength of SupportB+ CoverageA- Formula Quality
Acetyl L-Carnitine · 1 Gram(s)Caffeine · 180 mg

Acetyl-L-carnitine supports mitochondrial transport, while caffeine and theobromine provide a clear thermogenic pathway. The fully disclosed formula gives meaningful amounts of its main metabolic actives.

Citrulline, beta-alanine, and theanine support workout use rather than adding direct metabolic breadth. People sensitive to stimulants should consider the combined caffeine and theobromine exposure.

Study evidence
Acetyl L-Carnitine Adverse 1 study
Caffeine Disputed 40 studies
Productivity Boost
Productivity Boost
Impact
Highest effect
A- Goal FitB+ Strength of SupportB+ CoverageA- Formula Quality
Acetyl L-Carnitine · 1 Gram(s)Acetyl L-Carnitine · 1 Gram(s)Theanine · 90 mgCaffeine · 180 mg

Caffeine, L-theanine, and acetyl-L-carnitine create a strong alertness-and-focus stack. Exercise ingredients broaden the formula toward workout performance rather than desk-based productivity.

Caffeine is clearly disclosed at a substantial amount and theanine may soften its sharper effects. Stimulant-sensitive users may experience jitters, a faster heartbeat, or sleep disruption, especially when taken late.

Study evidence
Acetyl L-Carnitine Supportive 1 study
Acetyl L-Carnitine Supportive 1 study
Caffeine Supportive 108 studies
Theanine Supportive 5 studies
Fitness
Fitness
Impact
Highest effect
A- Goal FitB Strength of SupportB CoverageA- Formula Quality
Citrulline · 2 Gram(s)Beta-Alanine · 1.6 Gram(s)Caffeine · 180 mg

Citrulline, beta-alanine, caffeine, and acetyl-L-carnitine create a clear pre-workout formula for blood flow, repeated effort, and focus. Caffeine is sensibly paired with L-theanine, and every active amount is disclosed.

Citrulline and beta-alanine are below common full daily performance amounts at one scoop, so label directions allowing two scoops materially change exposure. Two scoops also double the stimulant load, which can increase jitters, sleep disruption, or cardiovascular symptoms in sensitive users.

Study evidence
Caffeine Supportive 255 studies
Citrulline Supportive 45 studies
Weight Loss
Weight Loss
Impact
High effect
B Goal FitB+ Strength of SupportC CoverageB Formula Quality
Caffeine · 180 mg

A meaningful caffeine amount may modestly raise thermogenesis and improve workout effort. Citrulline, beta-alanine, acetyl-L-carnitine, and theanine support training more than direct fat loss.

The formula does not manage hunger or support thyroid-related metabolism, so weight effects depend on diet and exercise. Caffeine and theobromine can cause sleep, anxiety, or cardiovascular side effects in sensitive users.

Study evidence
Caffeine Disputed 14 studies
Theanine Not classified

No linked studies yet.

Muscle Gain
Muscle Gain
Impact
Moderate effect
C+ Goal FitC- Strength of SupportC- CoverageB- Formula Quality
Caffeine · 180 mgCitrulline · 2 Gram(s)Beta-Alanine · 1.6 Gram(s)

Citrulline, beta-alanine, and caffeine may support workout performance, but the formula is not strongly dosed for hypertrophy-related training volume. The ingredients have established performance roles, although the amounts limit transfer to meaningful muscle-gain outcomes.

Citrulline and beta-alanine are below common full performance targets at the stated serving. The ingredients form a reasonable light pre-workout combination. The combined stimulants may cause jitteriness or interfere with sleep in sensitive users.

Study evidence
Caffeine Supportive 31 studies
Citrulline Supportive 15 studies

Ingredients

IngredientAmount per serving
L-Citrulline
2 Gram(s)
Beta-Alanine
1.6 Gram(s)
Acetyl-L-Carnitine (Acetyl-L-Carnitine HCl)
 1 Gram(s)
Caffeine Anhydrous
180 mg
L-Theanine
90 mg
Theobromine
50 mg
Bioperine Black Pepper fruit extract
2.5 mg
Adults 18–50 Women
Report overview
Theobromine · 50 mg OverallScore85
A+ Active Ingredient Quality & BioavailabilityB+ Dose, Safety & Label TransparencyC Value

Standalone theobromine is clearly disclosed, but the amount is aimed more at sensitive users or a stimulant stack than at strong theobromine-focused effects. Caffeine and other performance ingredients provide most of the pre-workout impact, which also raises the combined stimulant load. Serving cost is close to the collection benchmark, while the supplied details do not establish a purity percentage or fully describe flavor-system excipients.

View ingredientView products
Caffeine · 180 mg OverallScore78
B Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyD- Value

Caffeine anhydrous is clearly disclosed at 180 mg, giving the pre-workout a moderate primary stimulant dose. Theobromine adds a smaller, clearly measured stimulant load, but no sustained-release technology is present. An above-median serving cost places it in the premium-priced tier.

View ingredientView products
Loading alternative details
74 Performance

Nitrosurge Shred Black Cherry

Jacked Factory
<p>Its label clearly provides 1 g of Acetyl-L-Carnitine as Acetyl-L-Carnitine HCl and 2.50 mg of Bioperine Black Pepper fruit extract, making it a more clearly defined caffeine and theobromine option. Compared with the original, its ingredient and goal alignment is stronger, although the added black pepper extract may not suit every medication regimen.</p>
73 Performance

Nitrosurge Shred Orange Pineapple

Jacked Factory JF
<p>Its label clearly provides 1 g of Acetyl-L-Carnitine as Acetyl-L-Carnitine HCl and 2.50 mg of Bioperine Black Pepper fruit extract, making it a more clearly defined caffeine and theobromine option. Compared with the original, its ingredient and goal alignment is stronger, although the added black pepper extract may not suit every medication regimen.</p>
87 Performance

Caffeine 200 mg

ALLMAX
<p>Its label clearly provides 200 mg of Caffeine as Caffeine Anhydrous, making it a more clearly defined caffeine option. Compared with the original, its ingredient and goal alignment is stronger, although it does not retain the original product’s theobromine coverage.</p>
84 Budget

L-Theanine & Caffeine

SR Sports Research
<p>Its label clearly provides 0.50 g of Total Fat, preserving relevant caffeine coverage. Compared with the original, it lowers the serving cost, although it does not retain the original product’s theobromine coverage.</p>
84 Budget

Smart Caffeine with L-Theanine

NS Natural Stacks
<p>Its label clearly provides 200 mg of L-Theanine, preserving relevant caffeine coverage. Compared with the original, it lowers the serving cost, although it does not retain the original product’s theobromine coverage.</p>
82 Budget

High Caffeine 200 mg

Natrol
<p>Its label clearly provides 75 mg of Calcium as Dicalcium Phosphate Dihydrate, preserving relevant caffeine coverage. Compared with the original, it lowers the serving cost, although it does not retain the original product’s theobromine coverage.</p>
74 Value

Hydroxycut Hardcore Elite

MuscleTech Performance Series
<p>Its label clearly provides 270 mg of Caffeine Anhydrous, keeping the formula relevant to caffeine. Compared with the original, the lower serving cost and ingredient detail create a useful quality-to-cost balance, although it does not retain the original product’s theobromine coverage.</p>
82 Value

Caffeine 200 mg

Best Naturals
<p>Its label clearly provides 25 mg of Calcium as Dicalcium Phosphate, keeping the formula relevant to caffeine. Compared with the original, the lower serving cost and ingredient detail create a useful quality-to-cost balance, although it does not retain the original product’s theobromine coverage.</p>
81 Value

Natural Caffeine

BodyTech
<p>Its label clearly provides 200 mg of Caffeine as Coffee, keeping the formula relevant to caffeine. Compared with the original, the lower serving cost and ingredient detail create a useful quality-to-cost balance, although it does not retain the original product’s theobromine coverage.</p>
Report alternatives

Sources

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

  1. Effect of caffeine ingestion on time trial performance in cyclists: a systematic review and meta-analysis.
    Chen B; Ding L; Qin Q; Lei TH; Girard O; Cao Y · Journal of the International Society of Sports Nutrition · 2024
    Meta-analysis15 studies pooledFitness 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. Sleep symptoms associated with intake of specific dietary nutrients.
    Grandner MA; Jackson N; Gerstner JR; Knutson KL · Journal of sleep research · 2014
    Cross-sectional study4,552 participantsEnergy forTheobromine
  4. 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 Fitness forCaffeine
  5. 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
  6. 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
  7. 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
  8. 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
  9. Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes.
    Guest N; Corey P; Vescovi J; El-Sohemy A · Medicine and science in sports and exercise · 2019
    Randomized trial101 participantsFitness forCaffeine
  10. 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
  11. Placebo in sports nutrition: a proof-of-principle study involving caffeine supplementation.
    Saunders B; de Oliveira LF; da Silva RP; de Salles Painelli V; Gonçalves LS; Yamaguchi G; Mutti T; Maciel E; Roschel H; Artioli GG; Gualano B · Scandinavian journal of medicine & science in sports · 2018
    Randomized trial42 participantsFitness forCaffeine
  12. 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
  13. 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
  14. 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
  15. Acute Effects of Caffeine Supplementation on Physical Performance, Physiological Responses, Perceived Exertion, and Technical-Tactical Skills in Combat Sports: A Systematic Review and Meta-Analysis.
    Delleli S; Ouergui I; Messaoudi H; Trabelsi K; Ammar A; Glenn JM; Chtourou H · Nutrients · 2022
    Meta-analysis26 studies pooledFitness forCaffeine
  16. 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 forCaffeine
  17. 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
  18. 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
  19. 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
  20. 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
  21. Oral acetyl-L-carnitine therapy reduces fatigue in overt hepatic encephalopathy: a randomized, double-blind, placebo-controlled study.
    Malaguarnera M; Vacante M; Giordano M; Pennisi G; Bella R; Rampello L; Malaguarnera M; Li Volti G; Galvano F · The American journal of clinical nutrition · 2011
    Randomized trial121 participantsEnergy forAcetyl L-Carnitine
  22. The supplementation of acetyl-L-carnitine decreases fatigue and increases quality of life in patients with hepatitis C treated with pegylated interferon-α 2b plus ribavirin.
    Malaguarnera M; Vacante M; Bertino G; Neri S; Malaguarnera M; Gargante MP; Motta M; Lupo L; Chisari G; Bruno CM; Pennisi G; Bella R · Journal of interferon & cytokine research : the official journal of the International Society for Interferon and Cytokine Research · 2012
    Randomized trial60 participantsEnergy forAcetyl L-Carnitine
  23. Acetyl-L-carnitine reduces depression and improves quality of life in patients with minimal hepatic encephalopathy.
    Malaguarnera M; Bella R; Vacante M; Giordano M; Malaguarnera G; Gargante MP; Motta M; Mistretta A; Rampello L; Pennisi G · Scandinavian journal of gastroenterology · 2011
    Randomized trial67 participantsEnergy forAcetyl L-Carnitine
  24. A prospective study to evaluate the efficacy and safety of oral acetyl-L-carnitine for the treatment of chemotherapy-induced peripheral neuropathy.
    Sun Y; Shu Y; Liu B; Liu P; Wu C; Zheng R; Zhang X; Zhuang Z; Deng Y; Zheng L; Xu Q; Jiang B; Ouyang X; Gao J; Xu N; Li X; Jiang S; Liang C; Yao Y · Experimental and therapeutic medicine · 2020
    Randomized trial239 participantsEnergy forAcetyl L-Carnitine
  25. Metabolomic biomarkers for (R, S)-ketamine and (S)-ketamine in treatment-resistant depression and healthy controls: A systematic review.
    Kumar R; Nuñez NA; Joshi N; Joseph B; Verde A; Seshadri A; Cuellar Barboza AB; Prokop LJ; Medeiros GC; Singh B · Bipolar disorders · 2024
    Systematic reviewEnergy forAcetyl L-Carnitine
  26. 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
  27. 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
  28. Acute Effect of Citrulline Malate on Repetition Performance During Strength Training: A Systematic Review and Meta-Analysis.
    Vårvik FT; Bjørnsen T; Gonzalez AM · International journal of sport nutrition and exercise metabolism · 2021
    Meta-analysis137 participants8 studies pooledEnergy forCitrulline
  29. Oral L-citrulline supplementation enhances cycling time trial performance in healthy trained men: Double-blind randomized placebo-controlled 2-way crossover study.
    Suzuki T; Morita M; Kobayashi Y; Kamimura A · Journal of the International Society of Sports Nutrition · 2016
    Randomized trial22 participantsEnergy forCitrulline
  30. Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness.
    Pérez-Guisado J; Jakeman PM · Journal of strength and conditioning research · 2010
    Randomized trial41 participantsEnergy forCitrulline
  31. Citrulline/malate promotes aerobic energy production in human exercising muscle.
    Bendahan D; Mattei JP; Ghattas B; Confort-Gouny S; Le Guern ME; Cozzone PJ · British journal of sports medicine · 2002
    Single-arm trial18 participantsEnergy forCitrulline
  32. The Effect of Citrulline Malate Supplementation on Muscle Fatigue Among Healthy Participants.
    Farney TM; Bliss MV; Hearon CM; Salazar DA · Journal of strength and conditioning research · 2019
    Randomized trial12 participantsEnergy forCitrulline
  33. The Effects of Combined Exercise with Citrulline Supplementation on Body Composition and Lower Limb Function of Overweight Older Adults: A Systematic Review and Meta-Analysis.
    Xie S; Li S; Shaharudin S · Journal of sports science & medicine · 2023
    Meta-analysis303 participants7 studies pooledFitness forCitrulline
  34. Effect of High-Intensity Interval Training Combined with L-Citrulline Supplementation on Functional Capacities and Muscle Function in Dynapenic-Obese Older Adults.
    Buckinx F; Gouspillou G; Carvalho LP; Marcangeli V; El Hajj Boutros G; Dulac M; Noirez P; Morais JA; Gaudreau P; Aubertin-Leheudre M · Journal of clinical medicine · 2020
    Randomized trial56 participantsFitness Muscle Gain forCitrulline
  35. Initial Dietary Protein Intake Influence Muscle Function Adaptations in Older Men and Women Following High-Intensity Interval Training Combined with Citrulline.
    Buckinx F; Marcangeli V; Pinheiro Carvalho L; Dulac M; Hajj Boutros G; Gouspillou G; Gaudreau P; Morais J; Noirez P; Aubertin-Leheudre M · Nutrients · 2020
    Randomized trial73 participantsFitness forCitrulline
  36. Effects of Citrulline alone or combined with exercise on muscle mass, muscle strength, and physical performance among older adults: a systematic review.
    Aubertin-Leheudre M; Buckinx F · Current opinion in clinical nutrition and metabolic care · 2021
    Systematic review250 participants6 studies pooledFitness Muscle Gain forCitrulline
  37. Combined Vs. Single Supplementation of L-Citrulline and Sodium Bicarbonate During Sprint Interval Training in Basketball Players: Effects on Physical Performance and Hormonal Adaptations.
    Wang Y; Wang Y; Qian K · Journal of sports science & medicine · 2025
    Randomized trial40 participantsFitness forCitrulline
  38. Acetyl-L-carnitine in the treatment of mildly demented elderly patients.
    Passeri M; Cucinotta D; Bonati PA; Iannuccelli M; Parnetti L; Senin U · International journal of clinical pharmacology research · 1990
    Randomized trial60 participantsMental Focus forAcetyl L-Carnitine
  39. Acetyl-L-Carnitine Supplementation During HCV Therapy With Pegylated Interferon-α 2b Plus Ribavirin: Effect on Work Performance; A Randomized Clinical Trial.
    Malaguarnera G; Pennisi M; Gagliano C; Vacante M; Malaguarnera M; Salomone S; Drago F; Bertino G; Caraci F; Nunnari G; Malaguarnera M · Hepatitis monthly · 2014
    Randomized trial62 participantsMental Focus Productivity Boost forAcetyl L-Carnitine
  40. [Psycho-functional changes in attention and learning under the action of L-acetylcarnitine in 17 young subjects. A pilot study of its use in mental deterioration].
    Lino A; Boccia MM; Rusconi AC; Bellomonte L; Cocuroccia B · La Clinica terapeutica · 1992
    Non-randomized trial17 participantsMental Focus forAcetyl L-Carnitine
  41. Acetyl-L-carnitine (ALC) in attention-deficit/hyperactivity disorder: a multi-site, placebo-controlled pilot trial.
    Arnold LE; Amato A; Bozzolo H; Hollway J; Cook A; Ramadan Y; Crowl L; Zhang D; Thompson S; Testa G; Kliewer V; Wigal T; McBurnett K; Manos M · Journal of child and adolescent psychopharmacology · 2008
    Randomized trial112 participantsMental Focus forAcetyl L-Carnitine
  42. Acetyl-L-carnitine for patients with hepatic encephalopathy.
    Martí-Carvajal AJ; Gluud C; Arevalo-Rodriguez I; Martí-Amarista CE · The Cochrane database of systematic reviews · 2019
    Meta-analysis398 participants5 studies pooledMental Focus forAcetyl L-Carnitine
  43. 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
  44. 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
  45. 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
  46. Effects of caffeine on mood and performance: a study of realistic consumption.
    Brice CF; Smith AP · Psychopharmacology · 2003
    Clinical trial24 participantsMental Focus forCaffeine
  47. 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
  48. 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 forTheanine
  49. 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 Productivity Boost forTheanine
  50. 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 forTheanine
  51. 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 forTheanine
  52. 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
  53. Low Bioavailability and High TMAO Production: Novel Insights Into Acetylcarnitine and Carnitine Metabolism.
    Krims-Davis K; Ozola M; Razzivina V; Gukalova B; Konrade I; Dambrova M; Liepinsh E · Molecular nutrition & food research · 2025
    Randomized trialMetabolism Boost forAcetyl L-Carnitine
  54. 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
  55. 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
  56. 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
  57. 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
  58. Effects of Acute Ingestion of Caffeine Capsules on Muscle Strength and Muscle Endurance: A Systematic Review and Meta-Analysis.
    Wu W; Chen Z; Zhou H; Wang L; Li X; Lv Y; Sun T; Yu L · Nutrients · 2024
    Meta-analysis14 studies pooledMuscle Gain forCaffeine
  59. Acute caffeine intake improves muscular strength, power, and endurance performance, reversing the time-of-day effect regardless of muscle activation level in resistance-trained males: a randomized controlled trial.
    Montalvo-Alonso JJ; Del Val-Manzano M; Cerezo-Telléz E; Ferragut C; Valadés D; Rodríguez-Falces J; Pérez-López A · European journal of applied physiology · 2025
    Randomized trial13 participantsMuscle Gain forCaffeine
  60. Wake up and smell the coffee: caffeine supplementation and exercise performance-an umbrella review of 21 published meta-analyses.
    Grgic J; Grgic I; Pickering C; Schoenfeld BJ; Bishop DJ; Pedisic Z · British journal of sports medicine · 2020
    Systematic review21 studies pooledMuscle Gain forCaffeine
  61. Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis.
    Grgic J; Trexler ET; Lazinica B; Pedisic Z · Journal of the International Society of Sports Nutrition · 2018
    Meta-analysis20 studies pooledMuscle Gain forCaffeine
  62. Caffeine increases strength and power performance in resistance-trained females during early follicular phase.
    Norum M; Risvang LC; Bjørnsen T; Dimitriou L; Rønning PO; Bjørgen M; Raastad T · Scandinavian journal of medicine & science in sports · 2021
    Randomized trial15 participantsMuscle Gain forCaffeine
  63. Impact of L-citrulline supplementation and whole-body vibration training on arterial stiffness and leg muscle function in obese postmenopausal women with high blood pressure.
    Figueroa A; Alvarez-Alvarado S; Ormsbee MJ; Madzima TA; Campbell JC; Wong A · Experimental gerontology · 2015
    Randomized trial41 participantsMuscle Gain forCitrulline
  64. Citrulline Supplementation Improves Microvascular Function and Muscle Strength in Middle-Aged and Older Adults with Type 2 Diabetes.
    Figueroa A; Dillon KN; Levitt DE; Kang Y · Nutrients · 2025
    Randomized trial16 participantsMuscle Gain forCitrulline
  65. Citrulline stimulates muscle protein synthesis in the post-absorptive state in healthy people fed a low-protein diet - A pilot study.
    Jourdan M; Nair KS; Carter RE; Schimke J; Ford GC; Marc J; Aussel C; Cynober L · Clinical nutrition (Edinburgh, Scotland) · 2016
    Randomized trial8 participantsMuscle Gain forCitrulline
  66. Effects of caffeine on alertness.
    Zwyghuizen-Doorenbos A; Roehrs TA; Lipschutz L; Timms V; Roth T · Psychopharmacology · 1990
    Randomized trial24 participantsProductivity Boost forCaffeine
  67. 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
  68. 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
  69. 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
  70. Acute caffeine supplementation as a nutrition-based strategy to mitigate sleep-loss-related cognitive and operational performance impairments in military personnel: a systematic review and meta-analysis.
    Wang R; Wang W; Meng L; Hao G; Gu G · Frontiers in nutrition · 2026
    Meta-analysis7 studies pooledProductivity Boost forCaffeine
  71. 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
  72. 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
  73. 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 forTheanine
  74. 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
    Cohort study58,157 participantsWeight Loss forCaffeine
  75. 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
    Randomized trial20 participantsWeight Loss forCaffeine
  76. 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
    Randomized trial30 participantsWeight Loss forCaffeine
  77. 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
    Non-randomized trial60 participantsWeight Loss forCaffeine
  78. The effects of caffeine intake on weight loss: a systematic review and dos-response meta-analysis of randomized controlled trials.
    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
    Meta-analysis606 participants13 studies pooledWeight Loss forCaffeine