A curated set of product surveys and controlled studies, showing favourable, null, mixed and physiological findings without treating one result as a verdict on the whole category.
Last reviewed 15 October 202621 evidence summariesCurated, not systematic
Each entry identifies the design, tested sample or market, result direction, original source and a limitation. The direction describes the measured outcome only: it is not a rating of a product as good, bad, safe or unsafe.
Causal boundary. A randomised trial can estimate the effect of the exact tested intervention against its comparison for the measured outcome and participants. It cannot automatically establish the effect of every energy drink, dose or consumer. Product surveys and observational sources describe distributions or associations; they do not establish causation.
Disclosure boundary. Every entry includes a funding and conflict note. When those details could not be verified, the note states that explicitly; an unknown status does not mean that no funding or conflict exists.
Composition and market evidence
Comparative product assessment; independence and laboratory claims are attributed to the project
Scope
151 products · 30+ countries · six continents · one exact product per brand
Result summary
Descriptive ranking under an organiser-defined framework — no health or regulatory determination
Source
Six Continents Index project website · 2026
Six Continents Index — Energy Drinks 2026
The project reports that products were compared using a 36-point quality index and that the ten finalists—not all 151 products—were submitted to SGS Switzerland for laboratory verification.
Limitation: A non-representative sample with one product per brand. The full product-by-product scoring matrix, operational scoring detail and complete laboratory records are not public, so the ranking cannot be independently reproduced from the published material alone.
Funding and conflicts: The project states that results were not influenced by paid participation, sponsorship, application or commercial involvement by the assessed brands. Energy Drink Facts has not independently audited that statement, the project’s governance or its finances.
Denmark · 12 products · accredited ISO 17025 analysis
Result summary
Descriptive — no causal claim
Source
DTU National Food Institute · 2026
Nutrient Content in Energy Drinks — DTU National Food Institute, 2026
Laboratory analysis covered energy, sugars, sodium, vitamins, taurine and other nutrient characteristics in selected sugar-sweetened, sugar-free and mixed formulations.
Limitation: A selected sample from one national market; not designed as a global ranking.
Funding and conflicts: Funding and conflict-of-interest details have not been verified for this summary. This does not establish the presence or absence of sponsorship or competing interests.
Proceedings of the Nutrition Society · DOI 10.1017/S0029665124007304
Benchmarking sugar and caffeine content — Ireland, 2024
The study examined products collected from Dublin supermarkets. Sugar was analysed by a public laboratory; caffeine values were taken from product labels.
Limitation: Convenience sample from one market; caffeine was not laboratory measured.
Funding and conflicts: Funding and conflict-of-interest details have not been verified for this summary. This does not establish the presence or absence of sponsorship or competing interests.
Island of Ireland · market comparison · 2015 and 2019 data
Result summary
Descriptive change within the sampled market
Source
Safefood · 2019
A Survey of Energy Drinks on the Island of Ireland — Safefood, 2019
The report documents serving sizes, sugar and caffeine in products available during a defined collection period and compares the results with an earlier survey.
Limitation: Time- and market-specific findings should not be generalised globally.
Funding and conflicts: Funding and conflict-of-interest details have not been verified for this summary. This does not establish the presence or absence of sponsorship or competing interests.
Major UK retailers · declared composition and reformulation
Result summary
Descriptive association — no causal claim
Source
BMJ Open. 2017;7:e018136
UK energy drink composition surveys, 2015–2017
Hashem, He and MacGregor examined declared sugar, energy, caffeine and serving-size information in major UK retailers and monitored reformulation over time.
Limitation: Composition was based principally on declared label data rather than laboratory measurement.
Funding and conflicts: Funding and conflict-of-interest details have not been verified for this summary. This does not establish the presence or absence of sponsorship or competing interests.
11 trained male cyclists · energy drink, matched caffeine and placebo
Result summary
Favourable versus placebo; no evidence of added benefit over matched caffeine
Source
Quinlivan et al. Int J Sports Physiol Perform. 2015;10(7):897–901. DOI 10.1123/ijspp.2014-0481
Energy drink, caffeine and cycling time-trial performance
Time-trial performance improved after both the tested energy drink and an equivalent caffeine dose compared with placebo. Performance did not differ significantly between the energy-drink and caffeine conditions.
Limitation: Small all-male trained sample, acute testing and one commercial formulation; the result does not establish an effect for other doses or products.
Funding and conflicts: Funding and conflict-of-interest statements could not be verified from the accessible publication material checked for this summary. This does not establish the presence or absence of sponsorship or competing interests.
18 recreational endurance runners · 500 ml tested drink versus non-caffeinated sugar-free placebo
Result summary
Favourable for five-kilometre treadmill time versus placebo
Source
Prins et al. J Strength Cond Res. 2016;30(11):2979–2990. DOI 10.1519/JSC.0000000000001391
Five-kilometre running performance
Participants completed the five-kilometre treadmill time trial faster after the tested caffeinated, sugar-containing drink than after the placebo condition.
Limitation: Small acute, product-specific sample. The drinks differed in caffeine, carbohydrate and other ingredients, so the trial cannot identify which component or combination produced the difference.
Funding and conflicts: Funding and conflict-of-interest statements could not be verified from the accessible publication material checked for this summary. This does not establish the presence or absence of sponsorship or competing interests.
12 trained cyclists · 500 ml drink with 160 mg caffeine and 54 g carbohydrate versus placebo
Result summary
Favourable for time-trial completion time versus placebo; perceived exertion unchanged
Source
Ivy et al. Int J Sport Nutr Exerc Metab. 2009;19(1):61–78. DOI 10.1123/ijsnem.19.1.61
Simulated cycling time-trial performance
Participants completed a standardised simulated cycling time trial faster after the tested drink than after placebo, while perceived exertion did not differ significantly.
Limitation: Very small, acute, fasted and product-specific sample. The design did not isolate caffeine, carbohydrate or the drink’s other ingredients.
Funding and conflicts: Funding and conflict-of-interest statements could not be verified from the accessible publication material checked for this summary. This does not establish the presence or absence of sponsorship or competing interests.
30 healthy physically active men · two 473 ml drinks and matched placebo
Result summary
Mixed: null maximal-exercise outcomes, one isometric result and acute blood-pressure changes
Source
Banks et al. J Int Soc Sports Nutr. 2024;21(1):2297988. DOI 10.1080/15502783.2023.2297988
Commercial drinks, graded exercise and blood pressure
Neither tested drink improved maximal oxygen consumption, time to exhaustion or peak power versus placebo. One drink improved an isometric impulse measure, and both increased systolic blood pressure at specified time points; ECG measures did not differ from placebo.
Limitation: All-male sample, acute laboratory protocol, multiple outcomes and two specific products; individual significant findings should not be generalised to overall performance or clinical safety.
Funding and conflicts: The article reports that one author began employment with a tested drink's manufacturer after study completion; the other authors declared no relevant competing interests.
20 male US college football players · caffeine-taurine drink versus matched placebo
Result summary
Null result for the main performance comparison
Source
Gwacham and Wagner. Int J Sport Nutr Exerc Metab. 2012;22(2):109–116. DOI 10.1123/ijsnem.22.2.109
Repeated sprint performance and anaerobic power
The beverage did not significantly improve sprint time or anaerobic power. The authors reported that participants’ usual caffeine use interacted with the treatment response.
Limitation: One small, all-male athlete sample and one formulation; the caffeine-use interaction complicates interpretation.
Funding and conflicts: Funding and conflict-of-interest statements could not be verified from the accessible publication material checked for this summary. This does not establish the presence or absence of sponsorship or competing interests.
11 trained male cyclists · energy drink, caffeine/carbohydrate cola and placebo
Result summary
Null performance result with mixed physiological measures
Source
Phillips et al. J Strength Cond Res. 2014;28(5):1443–1453. DOI 10.1519/JSC.0000000000000275
Twenty-five-mile simulated cycling race
Completion time did not differ significantly among conditions. Lactate and selected immune-related measures differed, but those changes do not establish a performance benefit or clinical harm.
Limitation: Very small sample; acute laboratory measures and one formulation do not establish longer-term effects.
Funding and conflicts: Funding and conflict-of-interest statements could not be verified from the accessible publication material checked for this summary. This does not establish the presence or absence of sponsorship or competing interests.
24 enrolled; 21 analysed · simulated highway driving after two hours of prior driving
Result summary
Favourable for simulated lane keeping and subjective sleepiness versus placebo
Source
Mets et al. Psychopharmacology. 2011;214(3):737–745. DOI 10.1007/s00213-010-2078-2
Prolonged simulated driving performance
During later simulator periods, the tested drink reduced lane weaving and self-reported sleepiness compared with placebo.
Limitation: A young sample and a driving simulator, not a road-crash study. Caffeine does not make driving while dangerously tired safe or replace sleep.
Funding and conflicts: Red Bull GmbH financially supported the study, supplied both drinks and held the treatment code until study completion and data analysis.
45 healthy young adult video gamers · 200 mg caffeine product versus sensory-matched inactive placebo
Result summary
Favourable for several acute cognitive measures; limited gaming-task result
Source
Schwager et al. J Am Nutr Assoc. 2024;43(1):33–47. DOI 10.1080/27697061.2023.2207096
Cognitive tests and gaming after a multi-ingredient drink
The tested drink improved several measured cognitive domains and mood scores compared with placebo. Of five video games, a difference was reported for the two-dimensional visuospatial game but not the other four; blood pressure also increased modestly.
Limitation: Acute study of one multi-ingredient formulation in a selected gamer sample, with many outcomes. Because the active drink and placebo differed by the complete active-ingredient blend, the study cannot assign the results to caffeine or another single component.
Funding and conflicts: Woodbolt Distribution/Nutrabolt funded the study and supplied the beverages; National Institutes of Health infrastructure support is also reported. One author began working for Nutrabolt after data collection, analysis, interpretation and the primary manuscript draft were complete; the other authors reported no relevant competing interests.
19 male physical-education students · tested drink versus placebo
Result summary
Favourable for selected reaction-time, handgrip and 30-second cycling outcomes
Source
Chtourou et al. Nutrients. 2019;11(5):992. DOI 10.3390/nu11050992
Reaction time and short-term maximal performance
The tested drink improved selected simple reaction-time and short-duration physical-performance measures compared with placebo in this acute experiment.
Limitation: Small all-male, acute and product-specific study with multiple endpoints; it does not establish a general effect across sports, populations or formulations.
Funding and conflicts: The article reports no external funding, and the authors declared no conflict of interest.
Favourable for secondary-memory and speed-of-attention composites; null for other cognitive and mood outcomes
Source
Scholey and Kennedy. Psychopharmacology. 2004;176(3–4):320–330. DOI 10.1007/s00213-004-1935-2
Whole drink, memory and speed of attention
The complete tested drink improved the study’s secondary-memory and speed-of-attention factors compared with placebo. Other measured cognitive and mood outcomes did not differ.
Limitation: Small acute study in fasted, caffeine-deprived participants with multiple outcomes. The whole-drink result cannot be assigned to one ingredient or treated as a lasting cognitive benefit.
Funding and conflicts: GlaxoSmithKline Consumer Healthcare R&D funded the study.
General adult population · evidence assessed for a proposed 40 mg caffeine condition
Result summary
Dose-conditional: not established at 40 mg; prior favourable assessment retained for at least 75 mg per serving
Source
EFSA NDA Panel. EFSA Journal. 2014;12(2):3574. DOI 10.2903/j.efsa.2014.3574
Caffeine dose and increased alertness
The panel found that the submitted evidence did not establish increased alertness under the proposed 40 mg condition. It retained its earlier conclusion for products containing at least 75 mg caffeine per serving, noting that most reaction-time studies below that amount found no effect.
Limitation: This is an assessment of caffeine under defined claim conditions, not a finding that every energy drink improves alertness. It does not replace product-specific evidence or an individual safety assessment.
Funding and conflicts: The opinion followed an application by SmithKline Beecham Limited submitted through the United Kingdom competent authority.
223 healthy adults aged 18–70 · repeated testing to five hours
Result summary
Null result across measured mood, cognitive and behavioural outcomes
Source
Garcia-Alvarez et al. Am J Clin Nutr. 2020;111(3):719–727. DOI 10.1093/ajcn/nqz343
Decaffeinated drink and perceived mental energy
The investigators detected no statistically significant or meaningful benefit from the tested decaffeinated drink across the measured mood, cognitive, behavioural or subjective-energy outcomes.
Limitation: The result concerns one caffeine-free formulation and the outcomes and time window tested; it does not address caffeinated products.
Funding and conflicts: The State of Oregon Department of Justice financed the study through a contract; the article also reports NIH/NINR training support for one author. Detailed author conflict statements have not been verified for this summary. Disclosure source ↗ (opens in a new tab)
16 resistance-trained adults · acute product and placebo conditions
Result summary
Mixed: higher acute energy expenditure, no detected muscular-performance or subjective benefit
Source
Harty et al. J Int Soc Sports Nutr. 2020;17:45. DOI 10.1186/s12970-020-00374-5
Caffeine-protein drink, energy expenditure and strength outcomes
Energy expenditure was higher after the tested drink than after placebo at the post-drink and post-exercise measurements. The study detected no between-condition difference in its muscular-performance or subjective outcomes.
Limitation: Small acute study of one 300 mg-caffeine, protein-containing product. The placebo differed in caffeine, protein and energy content, so the result cannot identify which component produced the metabolic difference or establish a lasting change in body weight.
Funding and conflicts: Vital Pharmaceuticals funded the project, selected the tested product and broad outcome areas, supplied coded drinks and held the blinding codes. The article reports that the sponsor did not collect or analyse data or write or revise the manuscript; one investigator was a paid consultant.
60 adults · 200 mg caffeine product · acute testing and 28 days of use
Result summary
Mixed: selected acute energy-expenditure, day-one fat-oxidation and task-specific cognitive effects; no sustained fat-oxidation difference at day 28
Source
Krieger et al. Nutrients. 2025;17(23):3793. DOI 10.3390/nu17233793
Energy expenditure, fat oxidation and selected cognitive outcomes
The tested drink increased energy expenditure at selected time points. Fat oxidation was higher at selected time points on day one but not after 28 days; selected cognitive outcomes also differed.
Limitation: Laboratory endpoints do not establish body-weight or fat-loss effects. The trial examined one proprietary product over 28 days and reported many outcomes and time points.
Funding and conflicts: Accelerator Active SHOC Energy funded the study. The article also reports that one author was employed by Health Guidance, Inc.
18 healthy adults · 946 ml energy drink and 320 mg caffeine control
Result summary
Physiological signal requiring replication
Source
Fletcher et al. J Am Heart Assoc. 2017;6:e004448. DOI 10.1161/JAHA.116.004448
High-volume drink, ECG and blood-pressure measures
Compared with the caffeine control, the tested high-volume drink produced a larger QTc change at two hours and higher systolic blood pressure at six hours. Several other measures showed no evidence of a difference.
Limitation: Small proof-of-concept study, no caffeine-free placebo, multiple comparisons and an unusually high volume consumed over 45 minutes; it did not measure clinical events.
Funding and conflicts: The article reports funding from the Clinical Investigations Facility at Travis Air Force Base and lists no disclosures.
27 healthy participants · mean age 14.5 years · 3 mg caffeine/kg
Result summary
Acute physiological signal for the tested dose and population
Source
Oberhoffer et al. Front Cardiovasc Med. 2022;9:862041. DOI 10.3389/fcvm.2022.862041
Acute blood-pressure response in children and adolescents
Compared with a sugar-similar placebo, the tested drink increased mean systolic and diastolic blood pressure during the four-hour observation period. Heart rate tended to be lower.
Limitation: Small, single-blind, acute study in healthy young participants; it did not test chronic use or clinical cardiovascular events and cannot establish effects of every product.
Funding and conflicts: The authors declared no commercial or financial relationships that could be construed as a potential conflict of interest.
This is a deliberately varied evidence map, not a systematic review or meta-analysis. Sources are included to show different study designs and result directions when the original publication is identifiable and its scope can be stated. Inclusion does not endorse the authors’ interpretation, and the number of entries in a direction must not be treated as a vote count.
Sources are excluded when the product or sample cannot be identified, methods are not described, the result is available only as an unattributed claim, or the link does not lead to an original publication or accountable project source. Corrections and additions follow the site’s versioned editorial method.