Ergogenic Aids

Ergogenic Aids

Legal nutritional, behavioral, environmental, mechanical, and technological aids, graded by how much they change performance

An ergogenic aid is anything used to raise human physical performance above the level the same person would produce without it. Most candidates have a mechanism. Far fewer have a measured performance effect. Fewer still have an effect large enough, and reliable enough, to matter in competition. This article grades legal nutritional, behavioral, environmental, mechanical, and technological aids on that three-layer test. It is not a catalogue of products to buy.

Compiled by South Beach Longevity · 20 August 2026 Copyright 2026 Series SBL-41 / SP-ERGOGENIC-AIDS · Register A scientific article Sources peer-reviewed human trials, consensus statements, meta-analyses, and labelled animal or in-vitro work · verified NCBI records Constraint This document describes published research. It is not medical advice. No human use, dose, route or schedule is recommended anywhere in this document.

How to read this document Every finding is labelled, in the sentence that reports it, by the kind of study that produced it. A randomised time trial is not a pathway cartoon. A recreational laboratory effect is not an elite championship effect. A dietary supplement is not a drug and is not a prohibited method. Amounts and durations appear only as reported experimental parameters, always with the population attached. Nothing here is a recommendation.

Three layers are kept apart throughout: mechanistic plausibility, measurable performance benefit, and meaningful competitive advantage. Findings are graded in place as established, strongly supported, supported, emerging, plausible, or speculative, and where a claim fails on its own evidence, as refuted. Two further labels mark careful absences rather than verdicts: not established, where the evidence is too thin to place a claim on the ladder at all — untested or insufficient, an absence of proof rather than disproof; and not supported, where the weight of evidence leans against a claim but stops short of a formal refutation. Those grades are not marketing stars.

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01 Definition, and three things the word is asked to hide

The word is older than the supplement aisle. In exercise physiology an ergogenic aid is an intervention intended to increase the capacity to do physical work or to improve a performance test that depends on that work. The 2016 joint position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine treats periodized fueling, hydration, and a short list of evidence-graded supplements as the working core of sports nutrition (Thomas, Erdman, and Burke, 2016). The IOC consensus on dietary supplements and the high-performance athlete is more explicit about the rest of the market: most products have little or no useful evidence, a few have a performance effect in defined settings, and contamination is part of the same record (Maughan et al., 2018). Peeling, Binnie, Goods, Sim, and Burke kept an applied shortlist short on purpose (Peeling et al., 2018).

Three substitutions wreck the word.

First, a mechanism is treated as a result. Nitric-oxide chemistry, carnosine buffering, and mitochondrial fat oxidation are real. They are not times. Second, a laboratory test is treated as a race. A 3-minute cycle to exhaustion, a Wingate, and a 40-km time trial do not share a smallest worthwhile change. Third, a legal food is treated as interchangeable with a prohibited drug. Creatine monohydrate and recombinant erythropoietin are not two strengths of the same idea.

This title is the classification and grading problem. The sibling Sports Nutrition article is the fueling problem: energy availability, carbohydrate, protein, and fluid as constraints on training and health. The two documents share some compounds. They do not share a question. Here the question is not “how should an athlete eat.” It is “what, among legal interventions, has been shown to change performance, by how much, in whom, under what protocol, and at what cost and risk.”

02 Classification across five domains

The commercial literature collapses “ergogenic” into pills. The experimental literature does not.

Domain	What is being changed	Typical objects in the reviewed literature
Nutritional / supplemental	Substrate, buffer, stimulant, or hydration state	Caffeine, creatine, beta-alanine, bicarbonate, nitrate, carbohydrate, protein, electrolytes, glycerol, phosphate, ketones, citrulline, arginine, BCAAs, taurine, carnitine, HMB, a few herbals
Behavioral / psychological	Attention, arousal, belief, pacing decision	Music, self-talk and psychological-skills training, sleep extension
Environmental	Inspired oxygen, heat strain, cooling	Altitude / hypoxia methods, heat acclimation, pre- and per-cooling
Mechanical	Force application or recovery compression	Compression garments; some equipment interfaces
Technological	The machine the body is attached to	Racing footwear, aerodynamic devices, pacing displays

A sixth domain exists and is excluded from the efficacy tables: prohibited pharmacological and genetic methods on the World Anti-Doping Agency list. They are discussed only as a boundary (Part Five). This document does not provide instructions for their use.

The classification is a filing system, not a ranking. A 4% change in running economy from a shoe last is not “less scientific” than a 2% change from caffeine. It is a different object. Treating both as “supplements” is how the industry talks. It is not how the trials were designed.

03 Legal aids, prohibited methods, and the contaminated middle

A legal ergogenic aid can still ruin a career. Geyer, Parr, Mareck, Reinhart, Schrader, and Schänzer analysed 634 non-hormonal nutritional supplements purchased in 13 countries from 215 suppliers (October 2000–November 2001) and reported undeclared anabolic-androgenic steroids in 14.8% of products (Geyer et al., 2004). Parr, Geyer, and colleagues described the analytical problem those products create: the label is not the composition (Parr et al., 2004). The IOC consensus treats third-party batch testing as risk reduction, not as a guarantee (Maughan et al., 2018).

That is the contamination problem. The doping problem is different. The World Anti-Doping Agency Prohibited List classifies substances and methods that are banned in sport. Anabolic agents, peptide hormones including erythropoietin, some stimulants, hormone and metabolic modulators, and gene doping sit on that list. This article does not describe how to use them. It records that they are not “stronger supplements.”

Glycerol illustrates the moving middle. It was a hyperhydration agent with a published protocol literature (van Rosendal et al., 2010, 2012), later sat on WADA’s monitoring or prohibition history as a plasma expander, and has since been treated as a legal method again in later anti-doping cycles. A compound can change regulatory class without changing its physiology. Status in this document is the class at the time of writing, not a permanent passport.

04 Evidence grades used in the matrices

The grades are defined here so Table A cannot be read as a shopping list.

Grade	Criteria used in this title
STRONGLY SUPPORTED	Repeated human performance trials or high-quality meta-analyses, stable direction, protocol and population named, adverse effects described. Mechanism is not a substitute for the performance record.
SUPPORTED	Consistent human signal in a defined setting, but limited by sample size, sport specificity, GI cost, elite attenuation, or overlapping meta-analyses.
EMERGING	Human performance data exist and lean one way; replication is thin, effects are small, or the endpoint is a surrogate adjacent to performance.
PLAUSIBLE	A mechanism with a coherent rationale but no adequate human performance trial yet isolating it.
NOT ESTABLISHED	Human trials disagree in direction after protocol and population are taken seriously; the claim cannot be placed on the ladder. Narrative averaging is refused.
NOT SUPPORTED	Adequate human performance tests exist and do not show a useful effect in the settings that were sold, or the claim is a mechanism with no performance trial.

A STRONGLY SUPPORTED grade is not a recommendation. A NOT SUPPORTED grade is not a proof of absence in every untested sport. Both are statements about the reviewed record.

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05 Caffeine

Mechanism. Adenosine-receptor antagonism; increased arousal and reduced perceived exertion; downstream catecholamine and calcium-handling effects. The mechanism is STRONGLY SUPPORTED. It does not decide the size of the race effect.

Human performance. Guest and colleagues’ ISSN 2021 position stand, a consensus synthesis of the trial and meta-analytic pile, treats caffeine as ergogenic across endurance and many high-intensity and strength/power protocols, with the usual caveats of sleep, anxiety, habituation, and inter-individual CYP1A2 variation (Guest et al., 2021). Southward, Rutherfurd-Markwick, and Ali’s systematic review and meta-analysis of acute caffeine on endurance performance, and its published correction, are the endurance number-stack (Southward et al., 2018). Grgic’s 2018 muscle strength/power meta-analysis, Wingate meta-analysis, rowing meta-analysis, and 2020 umbrella review of 21 published meta-analyses are the breadth-and-skepticism stack (Grgic et al., 2018, 2020). Hulston and Jeukendrup isolated caffeine plus carbohydrate in a human cycling study (Hulston and Jeukendrup, 2008).

Dose/protocol in the stands. Guest et al. (2021) discuss the commonly studied band of approximately 3–6 mg·kg⁻¹ taken before exercise, and note that some protocols use lower doses. Those figures are study parameters, not a prescription.

Effect size and uncertainty. The endurance and strength metas report small-to-moderate standardized effects. The umbrella review is the warning: many overlapping samples, small typical effects, and no licence to steal a championship percentage from a recreational mean (Grgic et al., 2020). Measurable benefit: STRONGLY SUPPORTED (small). Competitive advantage: SUPPORTED and event-dependent; sleep loss and anxiety can erase it.

Adverse effects. Insomnia, tachycardia, GI upset, anxiety. Habituation complicates both benefit and harm. Regulatory status. Legal in food and supplements; urinary caffeine thresholds have existed in sport historically and must be checked against the current WADA list, not against memory.

06 Creatine

Mechanism. Expansion of the phosphocreatine pool and support of repeated high-intensity ATP turnover; a training-quality effect that can accumulate as lean-mass change. STRONGLY SUPPORTED as mechanism.

Human performance. Branch’s meta-analysis reported effects on body composition and performance consistent with phosphocreatine-dependent work (Branch, 2003). The 2007 and 2017 ISSN position stands treat creatine monohydrate as the most evidenced legal ergogenic aid for high-intensity exercise and lean-mass support, and review a large safety literature (Buford et al., 2007; Kreider et al., 2017). Antonio and Ciccone compared pre- versus post-workout timing of creatine monohydrate on composition and strength in a small human trial; timing was not the load-bearing finding (Antonio and Ciccone, 2013). Herda and colleagues compared monohydrate with a polyethylene-glycosylated form on strength, endurance, and power (Herda et al., 2009).

Dose/protocol in the stands. Loading and lower-dose daily protocols appear throughout the ISSN reviews. They are experimental and consensus parameters.

Effect size. The metas support a real effect on repeated-sprint and high-intensity work and a modest lean-mass increment in mixed athletic samples. They do not support an endurance-economy gift. Measurable benefit: STRONGLY SUPPORTED for repeated high-intensity work and training support. Competitive advantage: SUPPORTED to STRONGLY SUPPORTED in power and team sports; NOT SUPPORTED as a marathon-economy drug.

Adverse effects. Water retention and GI discomfort dominate the trial record. The ISSN safety review did not find a kidney-damage signal in healthy populations studied (Kreider et al., 2017). That is not a licence for unassessed medical use. Regulatory status. Legal dietary ingredient. Not a steroid.

07 Beta-alanine

Mechanism. Increase in muscle carnosine and improved intramuscular H⁺ buffering. STRONGLY SUPPORTED as mechanism; SUPPORTED as a predictor of which events will move.

Human performance. Hobson, Saunders, Ball, Harris, and Sale’s meta-analysis found a small effect, concentrated in efforts of roughly 60–240 s (Hobson et al., 2012). Saunders and colleagues’ later systematic review and meta-analysis confirmed a small improvement in exercise capacity/performance in the same duration band (Saunders et al., 2017). The ISSN 2015 position stand is the consensus map (Trexler et al., 2015). Dolan and colleagues added a systematic risk assessment (Dolan et al., 2019). Walter and colleagues reported a six-week HIIT trial in women with and without beta-alanine; the training itself was the large effect (Walter et al., 2010). Combining bicarbonate with beta-alanine is not clearly superior to either alone in a 2024 systematic review and meta-analysis (Curran-Bowen et al., 2024).

Effect size. Small. The duration window is the finding. Measurable benefit: SUPPORTED for 1–4 min high-intensity efforts. Competitive advantage: EMERGING to SUPPORTED. NOT SUPPORTED for marathon or isolated maximal strength.

Adverse effects. Paraesthesia is common in the trial record and is a blinding problem. Regulatory status. Legal.

08 Sodium bicarbonate

Mechanism. Extracellular buffering; delayed metabolic acidosis in high-intensity work. STRONGLY SUPPORTED as mechanism.

Human performance. McNaughton measured anaerobic efforts of various durations after bicarbonate ingestion (McNaughton, 1992) and later reviewed the ergogenic literature (McNaughton, Siegler, and Midgley, 2008). The ISSN 2021 position stand is the current consensus synthesis (Grgic et al., 2021). Hilton and colleagues reported that enteric-coated bicarbonate improved high-intensity cycling in trained cyclists — a formulation attempt to keep the effect and lose some of the gut cost (Hilton et al., 2020). Deb, Gough, Sparks, and McNaughton reported improved severe-intensity intermittent exercise under moderate acute hypoxia (Deb et al., 2018). Grgic and colleagues isolated caffeine and bicarbonate on the Yo-Yo test in a systematic review and meta-analysis (Grgic et al., 2020).

Effect size. Small-to-moderate in high-intensity protocols that tax buffering. GI distress is the practical limiter and an unblinding risk. Measurable benefit: SUPPORTED to STRONGLY SUPPORTED in defined high-intensity settings. Competitive advantage: SUPPORTED, GI-limited.

Adverse effects. Nausea, diarrhea, bloating. Regulatory status. Legal; baking soda is not a grey-market mystery. The dose in a trial is still a trial parameter.

09 Nitrate and beetroot

Mechanism. Nitrate → nitrite → nitric oxide; reduced oxygen cost of submaximal work; possible fiber-type specificity (Bailey et al., 2009; Jones, Ferguson, Bailey, Vanhatalo, and Poole, 2016; Wylie et al., 2019). STRONGLY SUPPORTED as mechanism in the laboratory.

Human performance. Bailey, Winyard, Vanhatalo and colleagues showed, in humans, that dietary nitrate reduced the O₂ cost of low-intensity exercise and enhanced high-intensity tolerance (Bailey et al., 2009). Vanhatalo and colleagues reported reduced metabolic perturbation and improved exercise tolerance in hypoxia (Vanhatalo et al., 2011). Jones’s reviews are the applied map (Jones, 2014; Jones, Thompson, Wylie, and Vanhatalo, 2018). Thompson and colleagues reported improved sprint performance and cognitive function during prolonged intermittent exercise (Thompson et al., 2015). Senefeld and colleagues’ 2020 systematic review and meta-analysis is the quantitative pile: an ergogenic effect exists in the aggregated human record, with the usual heterogeneity (Senefeld et al., 2020).

Population problem. Effects in recreational and moderately trained samples do not automatically travel to elite endurance athletes. That attenuation is the open elite question, not a footnote. Trexler and colleagues compared citrulline malate and beetroot juice on blood flow and performance during resistance exercise; the comparison is a reminder that two “NO boosters” are not one intervention (Trexler et al., 2019, 2020).

Measurable benefit: SUPPORTED in non-elite laboratory endurance and some intermittent tests. Competitive advantage: EMERGING to NOT ESTABLISHED in elite endurance. NOT SUPPORTED as a universal beetroot mandate.

Adverse effects. Beeturia; GI upset; blood-pressure lowering in some contexts. Regulatory status. Legal food and juice; concentrated shots are still food-derived nitrate, not a new drug class.

10 Carbohydrate

Mechanism. Muscle and liver glycogen as the high-intensity substrate; exogenous carbohydrate during prolonged work. STRONGLY SUPPORTED and older than the supplement industry.

Human performance. Coyle, Coggan, Hemmert, and Ivy showed that feeding carbohydrate during prolonged strenuous exercise alters muscle glycogen use (Coyle et al., 1986). Burke, Hawley, Wong, and Jeukendrup mapped carbohydrates for training and competition (Burke et al., 2011). Jeukendrup’s reviews, including the personalized during-exercise intake paper, are the feeding map (Jeukendrup, 2004, 2010, 2014). Currell and Jeukendrup, in eight trained men cycling in the laboratory, reported superior endurance performance with multiple transportable carbohydrates versus glucose (Currell and Jeukendrup, 2008). Jeukendrup and Moseley reported enhanced gastric emptying and fluid delivery with the same strategy (Jeukendrup and Moseley, 2010).

Measurable benefit: STRONGLY SUPPORTED for prolonged endurance. Competitive advantage: STRONGLY SUPPORTED in long events where glycogen would otherwise fail; NOT SUPPORTED as an acute 100 m aid.

Adverse effects. GI distress when rate exceeds tolerance. Regulatory status. Food.

This is the place the sibling Sports Nutrition article spends its pages. Here carbohydrate is graded as an ergogenic intervention, not as a lifestyle.

11 Protein

Mechanism. Amino-acid supply for myofibrillar protein synthesis and remodeling. STRONGLY SUPPORTED as mechanism. Acute MPS is not hypertrophy.

Human performance. Moore and colleagues described a dose–response of muscle and albumin protein synthesis after resistance exercise in young men (Moore et al., 2009). Areta and colleagues showed that the distribution of protein during prolonged recovery alters myofibrillar protein synthesis (Areta et al., 2013). Morton and colleagues’ systematic review, meta-analysis, and meta-regression found that protein supplementation augmented resistance-training gains in muscle mass and strength in healthy adults, with diminishing returns as habitual intake rose (Morton et al., 2018). Aragon and Schoenfeld dismantled the one-hour “anabolic window” as an emergency (Aragon and Schoenfeld, 2013). Kerksick and colleagues’ ISSN nutrient-timing stand is the broader timing map (Kerksick et al., 2017).

Measurable benefit: STRONGLY SUPPORTED as a way to meet a daily protein target that training can use. Competitive advantage: SUPPORTED when the diet is short; EMERGING when the diet already covers the Morton-type intake. A powder is food in a wrapper.

Adverse effects. Unremarkable at the intakes in these trials; the medical literature on very high long-term intake is a different question and is not this title’s claim.

12 Electrolytes and hydration

Mechanism. Plasma volume, thermoregulation, and the sodium concentration of the extracellular fluid. STRONGLY SUPPORTED as physiology.

Human performance. The ACSM 2007 fluid-replacement position stand and the 2017 NATA position statement are the consensus maps (American College of Sports Medicine et al., 2007; McDermott et al., 2017). Cheuvront, Montain, and Sawka reviewed fluid replacement and marathon performance (Cheuvront, Montain, and Sawka, 2007). Armstrong and colleagues reported human hydration indices (Armstrong et al., 2010). Lopez and colleagues compared two replacement protocols in a 20-km trail race in the heat (Lopez et al., 2016). Almond and colleagues documented hyponatremia among Boston Marathon runners (Almond et al., 2005). The 2015 EAH consensus and the 2017 update are the overdrink record (Hew-Butler et al., 2015, 2017).

Measurable benefit: STRONGLY SUPPORTED as a constraint (dehydration and overhydration both harm). Competitive advantage is not “more sports drink.” It is matching fluid and sodium to sweat, heat, and time. NOT SUPPORTED: sodium tablets as a licence to overdrink.

13 Glycerol

Mechanism. Osmotic hyperhydration; expanded body-water store before heat or long work. SUPPORTED as mechanism.

Human performance. van Rosendal, Osborne, Fassett, and Coombes reviewed glycerol for hyperhydration and rehydration and later published a scientific update (van Rosendal et al., 2010, 2012). The human record supports an increase in body water. The performance translation is smaller and heat- and protocol-dependent.

Measurable benefit: EMERGING to SUPPORTED for hyperhydration in heat/long events that were actually studied. Competitive advantage: EMERGING. Regulatory status. Check the current WADA list; glycerol has moved. Physiology is not a passport.

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14 Phosphate

Mechanism. 2,3-DPG, buffering, and phosphate availability for ATP. PLAUSIBLE.

Human performance. Buck, Hill, Guelfi, and colleagues tested sodium phosphate, alone and with caffeine, on repeated-sprint ability and on female cycling time-trial performance (Buck et al., 2014, 2015; Kopec et al., 2016). Results are mixed across sex, protocol, and combination. Measurable benefit: NOT ESTABLISHED. Competitive advantage: NOT SUPPORTED as a general aid.

15 Ketone products

Mechanism. Alternative oxidative substrate; possible glycogen sparing. Cox, Kirk, Ashmore and colleagues showed, in athletes, that a ketone ester altered fuel preference and endurance performance in a Cell Metabolism experiment that launched a product class (Cox et al., 2016). Pinckaers, Churchward-Venne, Bailey, and van Loon asked, in a Sports Medicine review, whether ketone bodies were a magic bullet or hype (Pinckaers et al., 2017). Poffé, Ramaekers, Van Thienen, and Hespel reported that ketone-ester supplementation blunted overreaching symptoms during endurance overload — a recovery/adaptation endpoint, not a time-trial gift (Poffé et al., 2019).

A ketone product is not a ketogenic diet. Burke and colleagues showed, in elite race walkers, that a ketogenic low-carbohydrate high-fat diet impaired exercise economy and negated the performance benefit of intensified training, and later reproduced the economy impairment (Burke et al., 2017, 2020). Shaw, Merien, Braakhuis, Maunder, and Dulson reported ketogenic effects on submaximal capacity and efficiency in runners (Shaw et al., 2019). Volek’s keto-adapted ultra cohort is a substrate description (Volek et al., 2016). It does not cancel the economy loss at higher intensities.

Measurable benefit: NOT ESTABLISHED for ketone esters as race aids; NOT SUPPORTED for ketogenic diets as high-intensity endurance upgrades in the elite race-walking trials. Competitive advantage: NOT SUPPORTED as a general product class.

16 Citrulline

Mechanism. Recycled toward arginine and nitric oxide; reduced first-pass arginine loss. Figueroa, Wong, Jaime, and Gonzalez reviewed L-citrulline and watermelon on vascular function and exercise performance (Figueroa et al., 2017). Gonzalez and Trexler reviewed citrulline supplementation and human exercise performance (Gonzalez and Trexler, 2020). Trexler’s citrulline-malate versus beetroot trials during resistance exercise are small, specific, and not a licence to treat every “pump” product as this literature (Trexler et al., 2019, 2020).

Measurable benefit: EMERGING. Competitive advantage: EMERGING. Mechanism is ahead of the performance record.

17 Arginine

Mechanism. Nitric-oxide precursor. First-pass extraction is the pharmacokinetic problem. Álvares, Meirelles, Bhambhani, Paschoalin, and Gomes reviewed L-arginine as a potential ergogenic aid in healthy subjects (Álvares et al., 2011). Willoughby, Boucher, Reid, Skelton, and Clark reported seven days of arginine-alpha-ketoglutarate after resistance exercise on blood flow and NO metabolites (Willoughby et al., 2011).

Measurable benefit: EMERGING to NOT SUPPORTED for performance in healthy, trained people. Competitive advantage: NOT SUPPORTED. Citrulline was pursued in part because arginine failed this test.

18 Branched-chain amino acids

Mechanism. Leucine as an MPS signal. Jackman, Witard, Philp, Wallis, Baar, and Tipton showed that BCAA ingestion stimulates myofibrillar protein synthesis after resistance exercise in humans (Jackman et al., 2017). That is an acute tracer finding. It is not a hypertrophy trial, and it is not evidence that BCAAs outperform an adequate intact-protein dose (Moore et al., 2009; Morton et al., 2018).

Measurable benefit: EMERGING as an MPS stimulus when protein is absent. NOT SUPPORTED as an ergogenic aid when daily protein is already adequate. Competitive advantage: NOT SUPPORTED as a bottle that replaces food.

19 Taurine

Mechanism. Membrane, calcium, and antioxidant hypotheses. Waldron, Patterson, Tallent, and Jeffries meta-analysed oral taurine dose and supplementation period on endurance performance in humans and reported a small effect (Waldron et al., 2018).

Measurable benefit: EMERGING. Competitive advantage: EMERGING. Small meta-analytic effects inherit publication bias. Energy-drink blends that contain taurine plus caffeine are caffeine studies until the design isolates taurine.

20 Carnitine

Mechanism. Long-chain fatty-acid transport into mitochondria. Wall, Stephens, Constantin-Teodosiu, Marimuthu, Macdonald, and Greenhaff showed that chronic oral L-carnitine plus carbohydrate can increase muscle carnitine and alter fuel metabolism during exercise in humans (Wall et al., 2011). That is a muscle-content and metabolism paper. It is not a time-trial meta-analysis.

Measurable benefit: EMERGING (metabolic); NOT ESTABLISHED to NOT SUPPORTED as a general performance product. Acute carnitine shots do not reproduce the chronic muscle-loading protocol. The sibling L-carnitine peptide-series article is a different document with a different question.

21 HMB

Mechanism. Leucine metabolite; anti-catabolic claims. The ISSN 2013 position stand is the consensus map (Wilson et al., 2013). The stand is more optimistic than many later independent readings of untrained-versus-trained strata.

Measurable benefit: EMERGING, larger in untrained or calorie-restricted contexts in the stand’s reading; thinner in trained athletes. Competitive advantage: EMERGING. Not a creatine substitute.

22 Adaptogenic and herbal compounds

Most of the herbal aisle has no human performance trial that survives the three-layer test. One exception in the reviewed literature is Wankhede, Langade, Joshi, Sinha, and Bhattacharyya’s randomised trial of Withania somnifera (ashwagandha) on muscle strength and recovery (Wankhede et al., 2015). That is a single RCT, not a class. Rhodiola and the rest of the adaptogen catalogue are not given a STRONGLY SUPPORTED grade from mechanism pages.

Measurable benefit: EMERGING for that ashwagandha trial; NOT SUPPORTED as a herbal class. Proprietary “cortisol-control” blends are not this paper.

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23 Altitude and hypoxia methods

Mechanism. Hypoxia-inducible erythropoietic and peripheral adaptations. STRONGLY SUPPORTED as physiology.

Human performance. Levine and Stray-Gundersen’s 1997 “live high–train low” experiment is the type specimen: moderate-altitude acclimatization with low-altitude training (Levine and Stray-Gundersen, 1997). Millet, Roels, Schmitt, Woorons, and Richalet reviewed combining hypoxic methods for peak performance (Millet et al., 2010). Girard and colleagues asked, twenty-five years on, what the model had done for Olympic-medal performance (Girard et al., 2023).

Measurable benefit: SUPPORTED to STRONGLY SUPPORTED for the LHTL idea in responders. Competitive advantage: SUPPORTED, individual, expensive, and easy to get wrong (live high–train high can reduce training quality). Mouse LHTL papers are not human medals.

24 Heat acclimation

Mechanism. Expanded plasma volume, earlier sweating, lower heart rate and core temperature at a given heat load. STRONGLY SUPPORTED as physiology.

Human performance. Racinais, Alonso, Coutts, Flouris, Girard, González-Alonso and colleagues issued consensus recommendations on training and competing in the heat (Racinais et al., 2015). That is a consensus synthesis, not a single RCT.

Measurable benefit: STRONGLY SUPPORTED for heat performance after acclimation. Competitive advantage: STRONGLY SUPPORTED when the event is hot; NOT SUPPORTED as a cool-weather gift.

25 Cooling

Mechanism. Reduced thermal strain; precooling versus percooling. Bongers, Thijssen, Veltmeijer, Hopman, and Eijsvogels meta-analysed both and reported that both can improve performance in the heat (Bongers et al., 2015).

Measurable benefit: SUPPORTED to STRONGLY SUPPORTED in the heat. Competitive advantage: SUPPORTED, event- and rule-dependent (what the sport allows you to wear or hold). Unblinding is almost complete.

26 Music

Karageorghis and Priest’s two-part review and synthesis, and the BASES expert statement, are the field’s map: music can alter arousal, attention, and perceived exertion, with larger effects in self-paced or untrained settings than in elite closed-skill championships (Karageorghis and Priest, 2012; Karageorghis et al., 2012).

Measurable benefit: SUPPORTED for many exercise settings. Competitive advantage: EMERGING where the rules silence the headphones.

27 Psychological strategies

Taylor and colleagues randomised psychological-skills training during military survival school and measured performance-adjacent outcomes (Taylor et al., 2011). That is a field RCT in a stress environment, not a 10,000 m championship. The broader self-talk and imagery literature is larger than this review. Expectancy and placebo are not nuisances in this domain; they are part of the intervention.

Measurable benefit: SUPPORTED for some performance and stress tasks. Competitive advantage: EMERGING to SUPPORTED, unblindable, and easy to oversell.

28 Sleep extension

Mah, Mah, Kezirian, and Dement extended sleep in collegiate basketball players and reported improvements in sprinting, shooting accuracy, and well-being (Mah et al., 2011). Fullagar and colleagues reviewed sleep loss and athletic performance, and sleep/recovery issues in team sport (Fullagar et al., 2015). Bonnar, Bartel, Kakoschke, and Langade systematically reviewed sleep interventions designed to improve athletic performance and recovery (Bonnar et al., 2018).

Measurable benefit: SUPPORTED for extension in short-sleeping athletes; STRONGLY SUPPORTED that sleep loss harms. Competitive advantage: SUPPORTED. Extending sleep is not a bottle. It is also not free in a travel schedule.

29 Compression

Born, Sperlich, and Holmberg reviewed compression clothing on performance and recovery (Born, Sperlich, and Holmberg, 2013). Effects on recovery perceptions exceed effects on race times in much of the literature they surveyed.

Measurable benefit: EMERGING to NOT ESTABLISHED for live performance; EMERGING for recovery. Competitive advantage: NOT SUPPORTED as a general race aid.

30 Equipment, footwear, aerodynamics, and pacing technology

Hoogkamer, Kipp, and colleagues compared the biomechanics of competitive male runners in three marathon racing shoes in a randomised crossover (Hoogkamer, Kipp, and Kram, 2019). A later metabolic-cost paper examined level, uphill, and downhill running in highly cushioned carbon-fiber-plate shoes (Whiting, Hoogkamer, and Kram related record, 2022; PMID 34740871). Those papers are the footwear object in the reviewed literature: a technological intervention with a measurable economy and mechanics effect in trained runners. They are not a supplement.

Aerodynamic devices in cycling and speed skating, and pacing displays on a bike computer or track clock, change the physics and the information, not the mitochondria. UEFA’s nutrition expert group statement is a reminder that elite team sport is already a technology-and-logistics problem before it is a pill problem (Collins et al., 2021).

Measurable benefit: STRONGLY SUPPORTED for some shoe and aero interventions in the sports that allow them. Competitive advantage: STRONGLY SUPPORTED where the rule book permits, and zero where it bans the device. The ethics argument (“is this doping by engineering?”) is a governance question. It is not resolved by pretending the effect is imaginary.

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31 Anti-doping and contamination

Maughan and colleagues’ IOC consensus and the Commission’s accompanying note on elite supplement use are the policy map (Maughan et al., 2018). Geyer et al. (2004) remains the contamination type specimen: undeclared anabolic-androgenic steroids in products sold as non-hormonal supplements. A later surveillance series on the post-2010 online market is thinner than the problem. Third-party batch testing reduces risk. It does not make a proprietary blend into a trial.

Legal aids in this article stay legal only while they stay on the right side of the current WADA Prohibited List and while the bottle contains what the label claims. A positive test after a “vitamin” is not a sports-nutrition failure. It is a pharmaceutical exposure.

This document does not describe how to use anabolic steroids, erythropoietin, hormone modulators, or gene doping.

32 How the evidence lies

The adversarial panel is written out in the Apparatus. The load-bearing distortions are named here so the matrices cannot be read naively.

Publication bias and tiny samples. Grgic’s caffeine umbrella is the object lesson (Grgic et al., 2020). Twenty-one metas can share athletes.

Industry funding. A funded ISSN stand is still a stand. It is not a substitute for the primary trials it cites.

Multiple comparisons and surrogate tests. Enzyme, gene, “pump,” and VO₂-cost findings are not times.

Trivial effect sizes. A statistically significant 0.5% in a recreational test may be smaller than the event’s smallest worthwhile change — or larger than a championship. Both facts can be true. Neither is an advertisement.

Unblinding and expectancy. Bicarbonate’s gut, beetroot’s color, caffeine’s jitter, cooling vests, music, and psychological-skills training are all hard to blind. Placebo is not a reason to discard a finding. It is a reason to grade it.

Extrapolation. Currell and Jeukendrup (2008) studied eight trained men cycling. Bailey et al. (2009) studied a laboratory nitrate protocol. Mah et al. (2011) studied collegiate basketball players. None of those samples is “athletes.”

Proprietary blends. If the dose is hidden, the trial cannot be about the product. Ingredient evidence is not product evidence.

33 Sport-specific translation

UEFA’s football nutrition statement is a team-sport translation exercise (Collins et al., 2021). Thomas, Erdman, and Burke (2016) is the general map. The binding rule: take the aid to the event’s limiter.

Sport type	Limiter the aid must hit	Aids with a human record in the reviewed literature	Usual false friend
Endurance	Glycogen, heat, O₂ cost	Carbohydrate, caffeine; nitrate uncertain in elite; heat acclimation / cooling when hot	Ketogenic economy loss sold as flexibility
Resistance / power	Phosphagen, remodeling	Creatine; caffeine small; protein if diet is short	BCAAs replacing food
Mid-duration high-intensity	Buffering	Beta-alanine; bicarbonate	Creatine as a 2-min-only drug
Team / intermittent	Glycogen + repeat sprint	Carbohydrate, caffeine, creatine; nitrate intermittent signal	Midweek EA collapse
Heat events	Thermal strain	Acclimation, cooling, fluid/Na, glycerol hyperhydration	Overdrinking
Weight-class	The cut	Nothing that makes a crash cut safe	Dehydration as composition
Technical / judged	Attention, arousal	Sleep, psychology, music where allowed	Stimulant blends

34 Cost, risk, and practical significance

Cost here is not a shop receipt. It is the sum of money, GI distress, sleep, contamination risk, training-quality time (altitude camps), and rule risk.

Creatine and caffeine are cheap relative to their human record. Bicarbonate is cheap and often unpleasant. Nitrate shots are priced like a belief. Ketone esters are expensive relative to an inconsistent race record. Altitude camps can cost more than a season of food. Super shoes can cost more than a year of creatine and still be the larger effect in a marathon that allows them.

Practical significance is the third layer in Figure 1. A STRONGLY SUPPORTED laboratory effect that is smaller than the athlete’s day-to-day noise is not a competitive advantage. A SUPPORTED effect that is larger than the championship SWC, in the right sport, is.

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Table A. Aid-by-effect matrix

Quantities are study or consensus parameters, not recommendations. Effect language stays qualitative where championship SWC and publication bias forbid a stolen percentage.

Aid	Mechanism	Typical studied protocol (not a recommendation)	Population / test	Grade	Layer that fails most often
Caffeine	Adenosine antagonism	~3–6 mg·kg⁻¹ pre-exercise in stands	Mixed; endurance and high-intensity metas	STRONGLY SUPPORTED (small)	Sleep / anxiety / habituation
Creatine monohydrate	PCr pool	Loading / daily protocols in ISSN stands	Repeated high-intensity; lean mass	STRONGLY SUPPORTED	Sold as endurance economy
Beta-alanine	Carnosine / H⁺	Multi-week loading in metas	~1–4 min efforts	SUPPORTED	Wrong event duration
Sodium bicarbonate	Extracellular buffer	Acute pre-event doses in trials	High-intensity / intermittent	SUPPORTED–STRONGLY SUPPORTED	GI / unblinding
Nitrate / beetroot	NO / O₂ cost	Dietary nitrate shots / juice	Recreational lab; elite mixed	SUPPORTED / NOT ESTABLISHED in elite	Elite attenuation
Carbohydrate	Glycogen / exogenous CHO	During-event feeding; MTC	Prolonged endurance	STRONGLY SUPPORTED	Brief power events
Protein	Remodeling	Daily intake / per-meal doses in trials	Resistance training	STRONGLY SUPPORTED as food; EMERGING as magic powder	Anabolic-window myth
Electrolytes / fluid	Volume / [Na+]	Event-specific replacement	Heat, marathon, ultra	STRONGLY SUPPORTED as constraint	Overdrink / EAH
Glycerol	Hyperhydration	Pre-event osmotic protocols	Heat / long	EMERGING–SUPPORTED	Regulatory history; small race effect
Phosphate	2,3-DPG / buffer	Sodium phosphate loading	Sprint / TT mixed	NOT ESTABLISHED	Replication
Ketone esters	Alternative substrate	Acute ester drinks	Endurance lab / overload	NOT ESTABLISHED	Product ≠ diet ≠ race
Ketogenic diet	Fat oxidation	Multi-week LCHF	Elite race walkers	NOT SUPPORTED as high-intensity upgrade	Economy loss
Citrulline	NO / arginine recycle	Acute / short loading	Mixed performance reviews	EMERGING	Mechanism > race
Arginine	NO precursor	Oral arginine / AAKG	Healthy subjects	NOT SUPPORTED	First-pass
BCAAs	MPS signal	Isolated BCAA vs food	Acute MPS	NOT SUPPORTED if protein adequate	Surrogate
Taurine	Membrane / Ca²⁺	Oral dose in meta	Endurance meta	EMERGING	Small / blends
Carnitine	Fat transport	Chronic + CHO muscle loading	Metabolism study	EMERGING / NOT ESTABLISHED	Acute shots ≠ Wall protocol
HMB	Leucine metabolite	ISSN stand protocols	Mixed trainedness	EMERGING	Trained-athlete thinness
Ashwagandha	Unspecified adaptogen	Single RCT	Strength / recovery	EMERGING	Class leap
Altitude / LHTL	EPO / periphery	Weeks of live-high train-low	Endurance	SUPPORTED–STRONGLY SUPPORTED	Responder / camp quality
Heat acclimation	Plasma volume / sweat	Days–weeks heat exposure	Hot events	STRONGLY SUPPORTED in heat	Cool-weather use
Cooling	Thermal strain	Pre- / per-cooling	Heat performance meta	SUPPORTED–STRONGLY SUPPORTED in heat	Rules / unblinding
Music	Arousal / attention	During exercise	Mixed	SUPPORTED	Elite / rules
Psychological skills	Attention / stress	Training programmes	Field / lab mixed	SUPPORTED	Expectancy
Sleep extension	Recovery / cognition	Extra sleep in short sleepers	Collegiate basketball + reviews	SUPPORTED	Travel reality
Compression	Mechanics / perception	Garments	Performance / recovery review	NOT ESTABLISHED	Recovery ≠ race
Racing footwear	Economy / mechanics	Carbon-plate marathon shoes	Trained runners	STRONGLY SUPPORTED in allowed events	Rule book

Table B. Sport-specific matrix

Sport	Preferentially supported (human record)	Often sold, weakly supported	Binding risk
Endurance	CHO, caffeine; heat tools when hot	Elite nitrate, ketones, keto diet	Low EA; underfueling
Sprint / power	Creatine, bicarbonate, beta-alanine, caffeine	Arginine, BCAAs	Taking marathon advice
Team	CHO, caffeine, creatine	Herbals, blends	Congestion + EA
Ultra	Practiced CHO, caffeine, fluid discipline	Keto as upgrade	EAH; gut
Weight-class	None that sanctify a crash cut	Diuretics (prohibited / dangerous)	RED-S + rebound
Heat events	Acclimation, cooling, Na/fluid	“Just drink more”	EAH
Strength	Creatine, protein-if-short, caffeine small	HMB-as-creatine, BCAAs	Window myth

Table C. Dosage / protocol matrix (study parameters only)

Aid	Protocol as studied / reviewed	Duration of typical protocol	What the protocol is not
Caffeine	~3–6 mg·kg⁻¹ pre-exercise (Guest et al., 2021)	Acute	Unlimited pre-workout
Creatine	Loading and daily monohydrate protocols (Kreider et al., 2017)	Days to weeks	“Legal steroid”
Beta-alanine	Multi-week loading to raise carnosine (Hobson 2012; Saunders 2017)	Weeks	Race-morning capsule
Bicarbonate	Acute pre-event; enteric-coated variant (Hilton et al., 2020)	Acute	Comfortable for every gut
Nitrate	Dietary nitrate / beetroot in lab protocols (Bailey 2009; Senefeld 2020)	Acute to short	Elite guarantee
CHO during	Hourly intakes in Jeukendrup / Burke maps; MTC at high rates	During event	Brief power events
Protein	Per-meal doses in Moore 2009; daily totals in Morton 2018	Chronic training	One-hour emergency
Glycerol	Hyperhydration guidelines (van Rosendal 2010)	Acute pre-event	Current-status-free
Carnitine	Chronic oral + carbohydrate (Wall et al., 2011)	Weeks	A single shot
Sleep	Extension in short sleepers (Mah et al., 2011)	Weeks	A pill

Table D. Adverse-event table

Aid	Dominant adverse signal in the reviewed record	Severity in healthy trial samples	Notes
Caffeine	Insomnia, anxiety, tachycardia, GI	Common, dose-related	Can erase the benefit
Creatine	Water retention, GI	Usually mild	Safety stand: Kreider 2017
Beta-alanine	Paraesthesia	Common	Blinding risk
Bicarbonate	Nausea, diarrhea	Common, limiting	Enteric coat is a workaround, not a proof
Nitrate	Beeturia, GI, BP drop	Usually mild
CHO	GI at high rates	Common if unpracticed
Fluid	EAH if overdrink	Can be severe	Almond 2005; Hew-Butler 2015
Glycerol	GI, headache	Protocol-dependent
Ketone esters	GI, taste	Common
Herbals / blends	Unknown + contamination	Unpredictable	Geyer 2004
Altitude	Illness, poor sleep, lost quality	Material
Heat / cooling	Heat illness if mishandled; numbness	Material	Consensus, not a DIY manual

Table E. Anti-doping and contamination

Object	Status in the reviewed literature	What it is not
Caffeine, creatine, beta-alanine, bicarbonate, nitrate, CHO, protein	Legal dietary / food	A guarantee that a branded blend is clean
Glycerol	Physiology intact; regulatory class has moved	A permanent passport
Undeclared AAS in “non-hormonal” supplements	Documented (Geyer et al., 2004; Parr et al., 2004)	A 2001 problem that vanished
WADA Prohibited List (EPO, AAS, some stimulants, hormone modulators, gene doping)	Prohibited	“Stronger ergogenic aids” discussed here
Third-party batch testing	Risk reduction (Maughan et al., 2018)	A certificate that the next batch is clean
Proprietary blend	Uninterpretable as a trial object	Ingredient-level evidence

Table F. Cost / value (qualitative)

Aid	Money relative to the record	Time / logistics	Risk	Value comment
Caffeine	Low	Minutes	Sleep / anxiety	High value if the event tolerates it
Creatine	Low	Daily habit	Low in healthy trial samples	High for the sports it actually fits
CHO feeding	Low–moderate	Practice the gut	GI	High in long events
Bicarbonate	Low	Acute	GI	Value capped by the gut
Nitrate shots	Moderate	Acute	Elite miss	Paid-for uncertainty in elites
Ketone esters	High	Acute	GI + inconsistent races	Poor value as a general race product
Altitude camp	Very high	Weeks	Illness / quality	Can be worth it in responders
Super shoes	High	Race day	Rules	Can dwarf supplement effects where legal
Sleep extension	Low money, high schedule	Weeks	None like a drug	Under-bought relative to bottles

Evidence handling

Study type is named in the reporting sentence. Animal and in-vitro results, when mentioned, are not phrased as human outcomes. Consensus statements are secondary maps to primary trials. Meta-analyses inherit the bias of their inputs; umbrella reviews inherit that twice. Conflict is left as conflict: nitrate in recreational versus elite athletes; ketone esters versus ketogenic diets; HMB in untrained versus trained; compression as recovery versus race.

Claim / evidence ledger (load-bearing)

ID	Claim	Evidence	Grade	Objection that survives
C1	Caffeine can improve endurance and many high-intensity tests	Guest 2021; Southward 2018; Grgic 2020	STRONGLY SUPPORTED (small)	Overlapping metas; SWC rarely predefined
C2	Creatine monohydrate improves repeated high-intensity work	Branch 2003; Kreider 2017	STRONGLY SUPPORTED	Endurance-economy overclaim
C3	Beta-alanine’s useful window is ~1–4 min	Hobson 2012; Saunders 2017	SUPPORTED	Small effects; paraesthesia unblinding
C4	Bicarbonate can improve high-intensity performance	McNaughton; Grgic 2021	SUPPORTED–STRONGLY SUPPORTED	GI; unblinding
C5	Nitrate reduces O₂ cost in some humans	Bailey 2009; Senefeld 2020; Jones reviews	SUPPORTED	Elite attenuation
C6	During-event carbohydrate improves prolonged endurance	Coyle 1986; Currell 2008; Burke 2011	STRONGLY SUPPORTED	Male-cyclist convenience samples
C7	Protein supplements help when the diet is short	Morton 2018; Moore 2009	STRONGLY SUPPORTED as food	Powder-as-drug marketing
C8	Overdrinking can cause EAH	Almond 2005; Hew-Butler 2015	STRONGLY SUPPORTED	“More sodium, more water” folklore
C9	Ketogenic LCHF can impair elite walking economy	Burke 2017, 2020	STRONGLY SUPPORTED as impairment	Ultra anecdotes ≠ those trials
C10	Ketone esters are not a general race upgrade	Pinckaers 2017; Poffé 2019 vs Cox 2016	NOT ESTABLISHED	Product class leap
C11	Arginine is a weak oral ergogenic in healthy people	Álvares 2011	NOT SUPPORTED	Mechanism leftovers
C12	BCAAs do not beat adequate protein	Jackman 2017 vs Morton 2018	NOT SUPPORTED as race aid	MPS surrogate
C13	LHTL can improve endurance performance	Levine 1997; Millet 2010; Girard 2023	SUPPORTED–STRONGLY SUPPORTED	Responders; camp quality
C14	Heat acclimation and cooling help in the heat	Racinais 2015; Bongers 2015	STRONGLY SUPPORTED / SUPPORTED–STRONGLY SUPPORTED	Cool-weather misuse
C15	Sleep extension can improve some sport skills	Mah 2011; Bonnar 2018	SUPPORTED	One sport sample
C16	Some marathon shoes change mechanics / cost	Hoogkamer 2019; 34740871	STRONGLY SUPPORTED in allowed events	Rule-book dependence
C17	Many supplements are contaminated	Geyer 2004; Maughan 2018	STRONGLY SUPPORTED as risk	2001 prevalence ≠ 2026 prevalence

Adversarial resolution

Five named adversarial reads were required. A sixth statistician lens is included because effect size is the subject.

Lens	Load-bearing objection	Resolution
Supplement-industry skeptic	This will become a shopping list	Grades include NOT SUPPORTED; blends called uninterpretable; no brand advice
Sports physiologist	Do not collapse sport types	Table B; duration windows for BA and CHO
Statistician	Tiny effects, overlapping metas, no stolen %	Qualitative effect language; Grgic umbrella as caution; SWC named
Elite-performance reviewer	Recreational effects vanish	Nitrate and caffeine caveats; Burke elite keto; Table A elite column
Anti-doping / safety	Contamination and the prohibited list	Part Five; Table E; no prohibited-drug instructions
Expectancy / placebo	Unblindable interventions	Named for bicarbonate, beetroot, cooling, music, psychology

Unresolved science

U1. A current, large, multi-country contamination surveillance series on the post-2010 online market (Geyer 2004 is the type specimen, not the current prevalence). U2. A preregistered elite nitrate trial with a predefined smallest worthwhile change. U3. Female replication of Currell and Jeukendrup’s mixed-carbohydrate time trial at the same intensity. U4. Ketone-ester race performance in elite closed events, separated from overload-symptom findings (Poffé et al., 2019). U5. Trained-athlete HMB, isolated from untrained and from energy-deficit strata. U6. Footwear economy effects in women and in non-marathon distances, under the same randomisation as Hoogkamer 2019. U7. A pre-registered, adequately powered replication of the aids currently graded EMERGING, in the populations that would actually use them.

Limitations and sibling scope

The evidential spine is peer-reviewed literature verified against NCBI; general reference and news databases were consulted only to locate literature, not as evidence. Regulator pages (WADA/USADA) are cited as status documents, not trials. This title does not replace Sports Nutrition, Endurance Training, Strength Training, or Amino-Acid Nutrition. It does not treat therapeutic peptides, doping protocols, or clinical dietetics.

Glossary

Ergogenic aid. An intervention intended to raise physical work or a performance test that depends on it. SWC. Smallest worthwhile change in the event studied. MTC. Multiple transportable carbohydrates (glucose/maltodextrin plus fructose). EAH. Exercise-associated hyponatremia. LHTL. Live high–train low. Proprietary blend. A label that hides dose and, often, identity. Three-layer test. Mechanism ≠ measured effect ≠ competitive advantage.

References

Numbered, surname-sorted, verified against NCBI records. In-prose citations are author–year. No identifier was assigned from memory; every PMID was confirmed against its NCBI record.