Health ConditionsSports physiology investigates the effect of exercise on the function and structure of the body. In a broad context, exercise physiology has evolved from the study of anatomy and physiology and examines how the body's structures and functions are altered when exposed to acute and chronic bouts of exercise. It is primarily the study of how the body adapts physiologically to the acute or short-term stress of exercise, and the chronic or long-term stress of physical training.
The factors influencing sports performance can be broadly categorized into endurance, muscular strength, flexibility, body proportions, speed, agility, mental control, disciplined performance, and nutrition.
Nutrition plays a crucial role in optimizing athletic performance, recovery, and overall well-being. Nutrition can play a crucial role in optimizing training sessions as well as with recovery and metabolic adaptation.
Athletic performance involves all of the organ systems of the body, not just muscles. Each organ system has a specialized role in energy metabolism.
Energy and macronutrient needs, especially carbohydrate and protein, must be met during times of high physical activity to maintain body weight, replenish glycogen stores, and provide adequate protein to build and repair tissue.
Research suggests that athletes tend to experience less calorie intake due to poor eating habits. Low knowledge of nutrition makes athletes practice wrong eating or dieting arrangements by relying on supplement intake to improve performance.
Sports nutrition is a key component for optimizing training, performance, injury prevention, and injury recovery. Nutritional recommendations need to be individualized for each athlete; thus, clinicians should be well informed to help determine proper caloric, macronutrient, micronutrient, and hydration intake based on the athlete's sport demands and training goals.
An athlete will have different macronutrient goals depending on sport, timing of exercise, and season status.
Adjusting dietary intake to meet sports nutrition recommendations has been found to improve outcomes such as body composition (increased muscle mass), competitive edge in performance (VOâ‚‚ max, handgrip strength, and sprint performance), and post-exercise recovery (carbohydrate improves glycogen resynthesis after endurance activities; protein increases muscle protein synthesis and decreases muscle degradation; and adequate energy and macronutrients reduce risk of injury).
Researchers have found that losing 2% of body fluids can affect performance and cognitive function. Thirst is often not an effective indicator of dehydration, as 1.5 L can be lost before thirst perception.
Athletes are susceptible to losing 0.3 to 2.4 L per hour of sweat, which includes not only water but also salt, potassium, calcium, magnesium, and chloride.
The significance of sleep and its vital contribution to athletic performance, cognitive function, overall health, and psychological well-being have received growing recognition. Research consistently demonstrates that sleep restriction negatively affects physical performance in both submaximal and maximal efforts. Following sleep deprivation, physiological strain increases, as evidenced by elevated heart rate, ventilation, respiratory frequency, and lactate accumulation, which collectively lead to earlier onset of fatigue and reductions in VOâ‚‚max. Sleep restriction also impairs anaerobic power, movement accuracy, muscle strength, and glycogen resynthesis, thereby limiting endurance and recovery capacity.
Sleep extension can improve sprint times, tennis serve accuracy, swim turn and kick stroke efficiency, swim sprint, basketball shooting accuracy, half-court and full-court sprints, and time to exhaustion. Enhanced cognitive function can include reaction times, psychomotor vigilance tasks, alertness, vigour, and mood. Athletes with adequate sleep reported less fatigue and sleepiness.
A systematic review concluded that increasing sleep duration at night or through napping was the most effective intervention to improve physical and/or cognitive performance.
Strong relationships have been found between changes in sleep quality and hormonal status, indicating that sleep improvement itself may enhance performance. Results emphasize the relevance of sleep for recovery and performance enhancement for athletes, and indicate that sleep interventions should be considered as an integral part of training programs in order to improve athletic performance to its fullest potential.
The timing of energy intake and the ratio of certain ingested macronutrients may enhance recovery and tissue repair, augment muscle protein synthesis (MPS), and improve mood states following high-volume or intense exercise. Endogenous glycogen stores are maximized by following a high-carbohydrate diet (8–12 g of carbohydrate/kg/day); moreover, these stores are depleted most by high-volume exercise.
Varied carbohydrate consumption not only improves carbohydrate availability without causing gastrointestinal upset but also carries the potential to enhance overall performance. For example, a study illustrated an 8% increase in power output during a time trial after 120 min of steady-state cycling when cyclists consumed beverages with a 2:1 ratio of glucose to fructose, as opposed to glucose alone.
Carbohydrate and hydration recommendations have not drastically changed in years, while protein and fat intake have been traditionally underemphasized in endurance athletes.
A meta-analysis of 28 studies involving 373 athletes found that overall, protein intake did not show a statistically significant improvement in athletic performance (standardized mean difference [SMD] = 0.12, 95% CI: −0.01 to 0.25). However, protein intake appears to provide modest benefits to athletes in improving their performance, particularly by enhancing endurance.
Meeting the total daily intake of protein, preferably with evenly spaced protein feedings (approximately every 3 h during the day), should be viewed as a primary area of emphasis for exercising individuals. Ingestion of essential amino acids (EAA; approximately 10 g) either in free form or as part of a protein bolus of approximately 20–40 g has been shown to maximally stimulate muscle protein synthesis (MPS). Pre- and/or post-exercise nutritional interventions (carbohydrate + protein or protein alone) may operate as an effective strategy to support increases in strength and improvements in body composition.
Athletes were advised on replacing high-saturated fats with unsaturated oils and limiting deep-fried foods, consistent with evidence showing benefits for musculoskeletal health and reduced inflammation.
Evidence from collegiate athletes indicates that dietary omega-3 intake is inadequate. A large study of NCAA Division I athletes revealed suboptimal omega-3 status, with an average Omega-3 Index of 4.3%, below the optimal target of ≥8%.
Defined as the delivery of adequate macronutrients precisely when the body is ready to use them, nutrient timing represents a dietary approach where specific nutrients are ingested before training to enhance both short-term performance and long-term adaptations.
Monitoring effective nutrient timing, such as consuming carbohydrates and proteins to enhance glycogen replenishment and accelerate muscle protein synthesis, is contingent upon maintaining proper nutrition.
The findings of a systematic review suggest that vitamins and minerals are crucial for an athlete's health and physical performance, and no single micronutrient is more important than others.
Currently the balance of the literature suggests that micronutrient supplementation in well-nourished athletes does not enhance physical performance. Excessive intake of dietary supplements may impair the body's physiological responses to exercise that supports adaptation to training.
When athletes have heightened overall energy requirements due to their training regimen, this increased need should reflect in both macro- and micronutrient intake. Meeting this demand through a well-rounded diet aligned with recommended dietary reference intakes for vitamins and minerals is generally achievable. However, certain scenarios, such as substantial losses through sweat and urine or specific dietary preferences, may lead to increased vitamin and mineral requirements. In instances where athletes face challenges in meeting their micronutrient needs through diet alone, supplementation may be beneficial.
Iron is an essential mineral responsible for oxygen transport in the blood, energy production, and immune function. Athletes, particularly those involved in endurance sports, require adequate iron intake to prevent anemia, maintain energy levels, and optimize performance.
Only iron and magnesium were assigned articles of sufficient quality to be ranked as "strong" in a systematic review of minerals and trace elements in athletes. Currently, there is little evidence to support the use of mineral/trace element supplementation to improve physiological markers of athletic performance, with the possible exception of iron (in particular, biological situations) and magnesium, which currently have the strongest quality evidence.
Vitamin D deficiency is highly prevalent among athletes, particularly in indoor sports and during the winter months. Athletes are often exposed to increased oxidative stress, higher metabolic turnover, and greater nutritional demands, which can potentially lead to deficiencies in vitamins.
Updated meta-analyses report that vitamin D3 supplementation can improve lower-limb muscle strength in athletes, with larger effects in those deficient at baseline. This selective performance enhancement raises questions about the mechanism of action and suggests that vitamin D's ergogenic effects may be more specific than previously thought, particularly in athletes with adequate baseline status.
Research has found that vitamin D supplementation could enhance elite athletes' strength, anaerobic power, and aerobic endurance; yet, more studies are needed to confirm its benefits on bone health and injury prevention.
Magnesium is an essential mineral involved in muscle function, nerve transmission, and energy production. Adequate magnesium intake is crucial for athletes to prevent muscle cramps, maintain optimal performance, and support recovery. Magnesium-rich foods include leafy greens, nuts, seeds, and whole grains.
Athletes are often exposed to increased oxidative stress, higher metabolic turnover, and greater nutritional demands, which can potentially lead to deficiencies in vitamins, making an understanding of vitamin supplementation as a function of sport discipline of fundamental importance.
Although the literature analysis allows for the establishment of specific doses of vitamins C and E, the recent consensus in sports nutrition emphasizes caution with antioxidant supplementation, as excessive or peri-exercise intake of these vitamins may attenuate key adaptive responses to training, including mitochondrial biogenesis and redox signaling.
Despite the widespread use of dietary supplements, the specific effects of different products on training adaptations and athletic performance vary considerably, and systematic evidence comparing the magnitude of these effects remains scarce. Currently, only a limited number of supplements—such as creatine, caffeine, buffering agents (e.g., β-alanine, sodium bicarbonate), and dietary nitrates—have received relatively consistent empirical support, demonstrating significant benefits for strength, explosive power, sprint speed, or training adaptations.
Traditional Use: Creatine monohydrate became widely adopted in sports settings from the early 1990s following research on its role in phosphocreatine regeneration. Its use has been traditional in strength and power sports communities.
Scientific Evidence: Creatine increases phosphocreatine stores and boosts high-intensity performance, particularly amplifying strength and power gains during resistance training. A network meta-analysis found creatine also reduced sprint time (SMD = −0.42, 95% CI −0.68 to −0.16; SUCRA = 94.57%; moderate-certainty evidence). Protein supplementation appears to be the most effective strategy for increasing muscular strength; β-alanine and creatine both improve jump performance, with β-alanine offering marginally superior effectiveness; and creatine is particularly beneficial for sprint speed.
Creatine improves high-intensity performance by replenishing phosphocreatine and ATP stores, improving strength, power, and lean muscle gains.
Traditional Use: Caffeine, derived from coffee, tea, and other plant sources, has a long history of use across cultures as a stimulant for mental alertness and physical endurance, predating its characterization as an ergogenic aid.
Scientific Evidence: Performance enhancers showed varying efficacy: caffeine (3–6 mg/kg) consistently improved power output and technical performance. Caffeine enhances alertness and focus and reduces perceived pain during exercise, improving overall performance. The timing and context of caffeine administration proved crucial; one study reported no performance improvements in 800 m running when caffeine was administered in the evening, with significant sleep quality impairment noted.
Traditional Use: Beta-alanine is a non-essential amino acid found naturally in animal-source foods. Its deliberate supplementation for athletic purposes is a more recent and scientifically driven practice, without a deep traditional herbal history.
Scientific Evidence: Beta-alanine improves exercise capacity by increasing skeletal muscle carnosine levels, which helps buffer the acid environment in skeletal muscle and thus reduces fatigue. Moderate-certainty evidence from a network meta-analysis indicated that β-alanine produced the greatest improvement in jump performance (SMD = 0.41, 95% CI 0.10–0.72; SUCRA = 89.0%) and ranked as the most effective intervention. The combination of creatine and β-alanine supplementation enhanced high-intensity exercise performance, particularly anaerobic power and repeated-bout performance, compared to creatine or β-alanine alone. No significant improvements in aerobic endurance capacity (VO₂max, lactate threshold, or time to exhaustion) were observed from creatine and β-alanine supplementation co-ingestion.
Traditional Use: Beets have been consumed medicinally in European folk traditions for centuries, though not specifically for athletic performance enhancement. The targeted use of concentrated beetroot juice as a nitrate source for sport is a development of modern sports science.
Scientific Evidence: Nitrate and nitrite have previously been thought of as mainly final elimination products of nitric oxide (NO), but evidence indicates that these compounds can be converted to NO in vivo. Beetroot juice (BRJ) supplementation was found to have an effect on oxygen cost and consumption during exercise by more efficient adenosine triphosphate (ATP) production in combination with lower ATP consumption. However, the effect seems to be dependent on dose and duration. The effect on exercise performance is conflicting; time to exhaustion seems to increase, but its effect on time-trial performance needs further elucidation.
Findings show that beetroot-derived nitrates can improve endurance, oxygen efficiency, muscular power, recovery, and cardiovascular function, particularly in recreationally active or moderately trained individuals. However, results are mixed in elite athletes, likely due to their already optimized nitric oxide utilization.
Nitrates, present in beetroot juice and leafy greens, boost muscle oxygen delivery, enhancing endurance.
Traditional Use: Ashwagandha is a foundational herb in Ayurvedic medicine, used for thousands of years in the Indian subcontinent as a rasayana (rejuvenating tonic). Traditionally prepared as a root powder or decoction in warm milk, it was used to promote vitality, physical endurance, and recovery from weakness or fatigue.
Scientific Evidence: Ashwagandha (Withania somnifera) is considered a potent adaptogen and anti-stress agent that could have some potential to improve physical performance. A PRISMA-based comprehensive systematic review and Bayesian meta-analysis evaluated clinical trials up to 2020 from multiple databases regarding the effect of Ashwagandha supplementation on physical performance in healthy individuals.
Results from a meta-analysis demonstrate that Ashwagandha supplementation, at a dosage of 300 mg to 500 mg of aqueous root extract daily, taken twice a day for a duration ranging from 8 to 12 weeks, is effective in enhancing sports performance compared with control or placebo groups. This includes improvements in cardiorespiratory fitness, muscle strength, recovery, and various physical fitness parameters. The primary finding of the meta-analysis indicates that, in comparison to a placebo, Ashwagandha significantly improved VO₂max in athletes by 4.09 ml/min/kg (95% CI, 2.55–5.63, p<0.001; I²=92%, p<0.001).
Ashwagandha is suggested to have beneficial effects on athletic performance through both indirect ways (improvement in sleep, regulation of stress and hormone levels) and direct actions such as anti-oxidative and anti-inflammatory properties, and possibly the promotion of muscle cell differentiation.
The evidence of the effects on VOâ‚‚max was initially classified as "high quality" due to all selected articles being RCTs, but the evidence dropped because of the small sample size and high degree of heterogeneity. The final quality of the evidence was rated as low. High-quality, large-scale randomized controlled trials are essential to strengthen the current evidence base.
Traditional Use: Rhodiola rosea has a documented history of use in Scandinavian, Russian, and Tibetan traditional medicine. Soviet researchers studied it extensively in the 1960s–1970s as a performance-enhancing agent for soldiers, athletes, and cosmonauts, administering it as a root extract to improve work capacity and resilience to stress.
Scientific Evidence: Rhodiola rosea significantly improved reaction and choice times in healthy men in a clinical study. Findings from a broad systematic review suggest that supplementation with adaptogens including Rhodiola may improve various aspects of sports performance, such as endurance and muscular strength, as well as health-related outcomes including anxiety reduction and improved sleep quality. Evidence is generally preliminary, and study populations have been small and heterogeneous.
Traditional Use: Panax ginseng has been used for over 2,000 years in traditional Chinese and Korean medicine as an adaptogenic tonic to restore and enhance wellbeing. The root was prepared as decoctions or powders and used to combat fatigue and improve stamina, mental clarity, and physical vitality.
Scientific Evidence: A review covering the top herbal adaptogens in the global market examined ginseng, among others, for its effect on the improvement of athletic performance including increases in muscle mass, endurance, and recovery of the athlete and possible side effects. Clinical evidence for Panax ginseng's ergogenic effects in human athletes remains inconsistent, with studies generally being small and of short duration, limiting conclusions about effect magnitude and optimal dosing.
Traditional Use: Cordyceps (Ophiocordyceps sinensis), a parasitic fungus, has been used in traditional Tibetan and Chinese medicine for centuries as a tonic for fatigue, respiratory capacity, and kidney function. It was traditionally consumed as a preparation with meat or in decoctions.
Scientific Evidence: Cordyceps was reviewed among the top herbal adaptogens in relation to its effect on muscle mass, endurance, and recovery in athletes. Proposed mechanisms include improvements in oxygen utilization and ATP production. However, human clinical trial evidence is limited, with most studies being small, short-term, and of varying methodological quality, meaning conclusions about ergogenic efficacy are preliminary.
Traditional Use: Eleuthero was the original adaptogen studied by Soviet researchers in the 1960s, when they sought to improve the work capacity and resilience of soldiers, athletes, and cosmonauts without stimulant side effects.
Scientific Evidence: Early Soviet-era studies suggested improved physical work capacity, though many of these studies did not meet modern methodological standards. Contemporary human clinical trial data for eleuthero as an athletic ergogenic aid is sparse, and it is considered a lower-evidence adaptogen compared to ashwagandha or rhodiola in relation to measurable athletic outcomes.
Traditional Use: Turmeric has been used for millennia in Ayurvedic and traditional South and Southeast Asian medicine as an anti-inflammatory agent, digestive tonic, and wound-healing preparation. It was typically consumed as a spice, paste, or decoction.
Scientific Evidence: Turmeric was reviewed among the top herbal adaptogens in the global market for effects on athletic performance including muscle mass, endurance, and recovery. Curcumin's anti-inflammatory properties have attracted interest in the context of exercise-induced muscle damage and recovery. Human studies are generally small and have investigated surrogate markers of inflammation and muscle soreness rather than direct performance outcomes. Evidence is preliminary and requires larger, well-controlled trials.
Strategies that may support athletic performance include practising healthy dietary habits, maintaining balanced macronutrient ratios, ensuring adequate micronutrient intake, and carefully using sports supplements and ergogenic aids.
Athletes consuming a diet rich in energy from nutrient-dense foods typically do not require vitamin and mineral supplements. However, those who struggle to meet their micronutrient needs may benefit from supplementation, guided by a sports nutritionist.
A narrative review has addressed diets with the most robust research evidence in humans regarding dietary impacts on athletic performance, critically evaluating the current level of evidence for the five most common diet patterns described in the literature.
High-protein and protein-paced versions of low-carbohydrate diets have also shown benefit for athletic performance. Plant-based diets have many variations, and vegans are at risk of micronutrient deficiencies and decreased leucine content.
Some athletes who eliminate certain whole food groups (e.g., vegetarian) may need to supplement their diet to avoid deficiencies.
Athletes may benefit from taking a multivitamin supplement if they are not meeting their micronutrient requirements or suffer from malabsorption or specific deficiencies in certain vitamins. However, athletes must avoid taking micronutrient supplements without first ensuring there is a deficiency.
Athletes, nutritionists, and coaches must work together to customize nutritional plans for each athlete to ensure that their needs are considered properly and they are receiving the sufficient level of nutrients they need to aid in the adaptation to their training and ultimately support optimal athletic performance.
Athletes often do not follow consensus dietary recommendations. In this context, it is important for nutrition professionals working with athletes to understand ways in which dietary intake can be modified.
1,3-DMAA (dimethylamylamine) is a synthetic stimulant formerly used in pre-workout supplements, with potent adrenergic effects on exercise performance. The FDA banned it from dietary supplements in 2012 due to serious safety risks including hemorrhagic stroke and cardiovascular events. Ergogenic evidence pre-dates the ban.
Several controlled human trials demonstrate that acai berry supplementation can improve exercise capacity and reduce exercise-induced oxidative stress in athletes. An RCT in elite athletes showed increased time to exhaustion at high intensity, and a cyclist crossover trial found reduced blood lactate and improved anaerobic threshold. Evidence is promising but based on small samples.
Agmatine is a decarboxylation product of arginine studied as a nitric oxide modulator with potential ergogenic effects. It inhibits nitric oxide synthase at high doses while potentially enhancing NO at lower doses, and has been proposed for vasodilation and performance enhancement in pre-workout contexts. Human RCT evidence for athletic performance is limited.
Alpha-ketoglutarate (AKG) is a Krebs cycle intermediate and nitrogen acceptor involved in glutamate and glutamine synthesis. Used in clinical and sports nutrition contexts as ornithine alpha-ketoglutarate (OAK) or arginine alpha-ketoglutarate (AAKG) for muscle protein synthesis support and recovery. The EBSCO Research Starters sports performance database lists it as a proposed ergogenic aid.
Studies on D-ribose and athletic performance show mixed results. Some trials report maintained or improved ATP levels and power output in exercising subjects, while others show no performance advantage over placebo. Effects appear more pronounced in untrained individuals or those recovering from intense exercise.
A 4-month randomized, double-blind, placebo-controlled trial in 40 male American football athletes found that AGIQ/EMIQ added to whey protein supplementation significantly affected body composition and oxidative stress markers compared to whey protein alone. Preclinical studies showed AGIQ intensifies muscle hypertrophy in mice. This is direct human RCT evidence in an athletic population.
An amylopectin-chromium complex (Velositol®) has been studied in human clinical trials in the context of resistance training. A double-blind crossover RCT found that combining 2 g of the complex with 6 g whey protein increased muscle protein synthesis by 48% from baseline vs. 24% for whey alone. An 8-week randomized, active-controlled, double-blind trial in recreationally active men reported improvements in repetitions to failure and vertical jump power with the amylopectin-chromium plus whey protein condition.
Arginine alpha-ketoglutarate (AAKG) combines L-arginine with AKG to potentially enhance nitric oxide production and ergogenic effects. Select RCTs show improvements in 1RM bench press and anaerobic power. It is commonly used as a pre-workout ergogenic aid and is listed as a proposed performance supplement in sports medicine databases.
Ashwagandha (Withania somnifera) has Ayurvedic traditional use for strength and endurance and is supported by multiple RCTs and systematic reviews showing improvements in VO2 max, muscular strength, and recovery in athletes. A 2025 systematic review of 11 systematic reviews (9,005 individuals) found promising effects on endurance and muscular strength.
Astaxanthin is a powerful carotenoid antioxidant found in microalgae that has shown ergogenic effects in RCTs, including improved cycling power output, reduced oxidative stress after exercise, and decreased exercise-induced muscle damage. Multiple controlled trials in athletes support its use for performance and recovery.
Oral ATP disodium supplementation (400 mg/day) has been studied in multiple RCTs for athletic performance. It prevents post-exercise ATP declines, maintains muscle excitability during repeated sprints, and combined with resistance training enhances muscular adaptations. Evidence from double-blind placebo-controlled trials supports its ergogenic potential.
A crossover RCT showed B. coagulans GBI-30, 6086 + casein prevented the decline in Wingate peak power observed in the protein-only group following muscle-damaging exercise. Improved protein absorption (BCAAs) and gut-muscle axis modulation are the primary mechanisms. Animal data further supports enhanced exercise endurance.
Multiple Appalachian State University RCTs demonstrated that banana ingestion during prolonged cycling matched carbohydrate sport drinks for performance and post-exercise inflammation. Banana metabolites inhibit COX-2 mRNA expression, suggesting an anti-inflammatory effect analogous to ibuprofen. Bananas also augment antioxidant capacity during exercise through unique phenolics.
Beef protein supplementation has been studied in RCTs and a meta-analysis across both resistance-trained and endurance athletes. Evidence shows it significantly increases lean body mass and lower-limb strength versus no protein, and supports a favorable anabolic environment in elite triathletes. Effects on performance are comparable to whey protein.
Beetroot is a natural source of inorganic nitrate, which is converted to nitric oxide in the body to improve vasodilation, oxygen efficiency, and exercise performance. Multiple systematic reviews confirm cardiorespiratory endurance benefits, particularly in recreational to moderately trained athletes. The nitrate-NO pathway is well characterized.
Beta-alanine is a rate-limiting precursor to muscle carnosine, an intracellular pH buffer. The ISSN position stand and multiple systematic reviews support its use for improving exercise capacity and performance, particularly in activities lasting 1–4 minutes. Typical dose is 4–6 g/day for at least 4 weeks.
Beta-glucan supplementation has been linked to improved muscle strength and exercise capacity in athletes in preliminary RCT evidence. Its immunomodulatory properties may also reduce post-exercise immunosuppression and upper respiratory tract infection risk, supporting training consistency. Evidence is emerging but mechanistically plausible.
A placebo-controlled pilot RCT (Bouic et al., 1999) in ultra-marathon runners found that beta-sitosterol and its glucoside significantly decreased the cortisol:DHEAs ratio and post-exercise immune suppression compared to placebo, suggesting modulation of the catabolic stress response to extreme endurance exercise. This is the primary human clinical evidence linking beta-sitosterol to athletic recovery, and larger confirmatory trials have not been published.
Betaine (trimethylglycine) is recognized by the NIH ODS as a studied ergogenic aid that may enhance performance via creatine biosynthesis upregulation, blood nitric oxide elevation, and cellular hydration. Limited RCT evidence in men shows potential benefits for power and strength-based exercise, though evidence is mixed.
Sodium bicarbonate is a well-established ergogenic buffer that increases extracellular buffering capacity, delaying fatigue during high-intensity exercise. A meta-analysis and systematic reviews confirm performance improvements in intense endurance events (45 seconds to 8 minutes). It is among the most studied legal ergogenic aids.
Bovine heart provides L-carnitine and CoQ10, both of which have been studied for ergogenic effects. Clinical data show L-carnitine supplementation increases maximum oxygen consumption, power output, and exercise capacity; CoQ10 similarly shows performance-supporting effects in trials. These are constituent-based findings; no RCTs of bovine heart supplement specifically for athletic performance exist.
Bovine liver has a long history in athletic communities dating to the 1930s, supported by its content of heme iron (oxygen transport), B12 (red blood cell production), CoQ10 (mitochondrial ATP synthesis), and complete protein. A classic rat study showed liver-fed animals had markedly improved swimming endurance. CoQ10 from liver has clinical trial support for anaerobic performance and fatigue reduction in athletes.
Clinical studies show bromelain reduces exercise-induced muscle damage, delayed-onset muscle soreness (DOMS), and inflammatory markers (CRP, IL-6) post-exercise. A randomized double-blind trial in competitive cyclists found bromelain (1000 mg/day over six race days) reduced subjective fatigue and showed a trend toward maintaining testosterone concentrations compared to placebo. Bromelain's proteolytic and anti-inflammatory properties underpin these effects.
The 2013 Nutrition Journal RCT demonstrated that 48 g/day of rice protein isolate over 8 weeks produced significant improvements in body composition, skeletal muscle growth, peak power, and strength in resistance-trained males, comparable to whey protein. A 2025 Frontiers in Nutrition review confirmed that plant protein blends including brown rice protein achieve myofibrillar protein synthesis rates similar to whey. These findings support its use as a performance-relevant protein source for athletes.
Caffeine is one of the best-supported ergogenic aids, with systematic reviews and meta-analyses confirming performance improvements at 3–6 mg/kg body mass. It consistently improves endurance, power output, sprint performance, and perceived exertion across multiple sports. It acts primarily via adenosine receptor antagonism in the central nervous system.
Casein supplementation supports strength and lean mass gains over long-term resistance training. When total protein intake is matched, casein produces hypertrophy and strength outcomes comparable to whey protein. Presleep casein also accelerates functional recovery in competitive athletes, enabling more consistent performance across training blocks.
Catechins—primarily EGCG—have been investigated for their roles in reducing exercise-induced muscle damage, attenuating oxidative stress during training, and enhancing fat oxidation during exercise. Multiple human and animal studies support improvements in recovery and endurance capacity. Evidence is stronger for recovery than for acute performance gains.
A meta-analysis of 10 RCTs (Journal of the American College of Nutrition, 2020) found that tart cherry concentrate significantly improved endurance exercise performance in trained athletes. Benefits are attributed to anti-inflammatory, antioxidant, and blood-flow-enhancing mechanisms, with effects most pronounced in trained individuals.
Multiple RCTs show chlorella supplementation reduces blood lactate and increases O2 pulse during cycling exercise. A 4-week RCT found a significant increase in VO2max compared to placebo. Evidence for direct performance gains (time-trial, WRmax) is mixed and preliminary.
Chloride, along with sodium, is the primary electrolyte lost in sweat during exercise. Depletion of chloride impairs fluid retention and electrolyte balance, which can reduce endurance performance. Oral rehydration solutions containing chloride have demonstrated superior performance preservation compared to plain water in human trials.
A 2023 systematic review of 10 human clinical trials in athletes (rowers, footballers, handball players, triathletes, runners) found that chokeberry supplementation reduced exercise-induced oxidative stress and inflammatory biomarkers. Effects on actual performance metrics were inconsistent. Chokeberry juice reduced TBARS in rowers during and after exercise.
Prolonged endurance exercise depletes plasma choline by up to 40–55%, which may impair neuromuscular function. Supplementation can prevent this depletion. Evidence for direct performance enhancement is modest and depends on whether choline is actually depleted during the activity. The choline form alpha-GPC has shown acute strength and power gains in small RCTs.
A human pilot study found that exercise-trained men taking 3,200 mg of Cissus quadrangularis daily for 8 weeks reported roughly one-third reduction in exercise-induced joint pain, supporting musculoskeletal recovery during training. The plant's anti-inflammatory, analgesic, and putative anti-catabolic properties underlie its popularity in sports nutrition. Evidence remains preliminary due to the absence of a placebo control in the key joint-pain trial.
CLA has been studied for ergogenic effects in athletes, primarily through body composition changes (reduced fat mass, preserved lean mass). Results from resistance-training RCTs are mixed; some show modest anti-catabolic effects and lean mass gains, while larger trials find no significant performance benefit for experienced athletes.
Collagen peptide (CP) supplementation combined with exercise shows strong evidence for improving tendon structural outcomes relevant to athletic performance, including increased tendon cross-sectional area and stiffness. A 24-week RCT in 147 collegiate athletes found 10 g/day collagen hydrolysate significantly reduced activity-related joint pain versus placebo. However, a 2024 meta-analysis of 13 RCTs found no significant effect of CP on strength-related performance outcomes, indicating benefits are primarily connective-tissue and pain-related rather than muscle-performance-related.
Bovine colostrum contains growth factors (IGF-1), immunoglobulins, and bioactive peptides proposed to enhance muscle mass, strength, and recovery. Multiple RCTs show benefits for lean body mass and exercise performance. The EBSCO Research Starters sports performance database lists it as a proposed ergogenic aid.
CoQ10 is an endogenous mitochondrial electron carrier proposed to enhance aerobic energy production and reduce exercise-induced oxidative stress. The NIH ODS exercise fact sheet directly addresses CoQ10, finding limited ergogenic benefit and noting one study where CoQ10 groups had smaller power improvements than placebo, suggesting potential interference with training adaptation.
Cordyceps (particularly Cordyceps militaris and CS-4) is studied for endurance and aerobic performance. An RCT found Cordyceps militaris improved tolerance to high-intensity exercise after acute and chronic supplementation. Proposed mechanisms include enhanced oxygen utilization and mitochondrial biogenesis. Evidence is promising but modest in humans.
Creatine is among the most extensively studied ergogenic aids in sports science. The ISSN position stand and multiple systematic reviews confirm it increases intramuscular phosphocreatine stores, improving high-intensity exercise performance, strength, and lean mass. A 2025 meta-analysis of 69 RCTs confirmed significant improvements in bench press and squat strength. Typical dosing is 3–5 g/day monohydrate.
Creatine monohydrate is the most researched and validated form of creatine for athletic performance. ISSN and multiple meta-analyses confirm it enhances high-intensity exercise capacity, strength, and muscle hypertrophy. It is consistently cited as the reference form in all creatine efficacy research.
New Zealand blackcurrant (NZBC) extract has been studied in multiple randomized controlled trials for effects on endurance performance and fat oxidation. Anthocyanin-induced vasodilation appears to increase blood flow to working muscles, potentially reducing fatigue and improving time-trial performance. A 2022 narrative review covering 17 placebo-controlled crossover studies confirmed consistent signals for performance and recovery benefits.
D-Aspartic Acid (DAA) has been marketed as an ergogenic aid based on its proposed ability to raise testosterone, which could theoretically enhance athletic performance. Multiple randomized controlled trials in resistance-trained men found no significant improvements in strength, body composition, or performance biomarkers compared to placebo. A systematic review of five RCTs using doses of 3–12 g/day over 2–12 weeks confirmed these null findings.
D-Ribose is a pentose sugar and structural component of ATP studied for improving energy recovery in athletes. While it shows benefits in populations with enzyme deficiencies impairing ATP synthesis, six small double-blind RCTs in healthy athletes failed to find ergogenic benefit. Its primary performance support evidence is limited.
DHEA is an endogenous adrenal hormone and testosterone/estrogen precursor studied for ergogenic effects. The EBSCO Research Starters sports performance database lists DHEA as a proposed ergogenic aid. Evidence for performance benefits in young healthy athletes is limited; benefits are more documented in older adults with low DHEA levels.
DMHA is a synthetic alkylamine stimulant used in pre-workout supplements as a replacement for DMAA, with proposed stimulant and ergogenic properties. Regulatory agencies including the FDA and WADA have flagged it as unsafe and prohibited. Limited human clinical data exist, with ergogenic classification based primarily on pharmacological class evidence.
Ecdysteroids are polyhydroxylated steroids found in plants (phytoecdysteroids) and insects with demonstrated anabolic and ergogenic properties. RCT evidence shows improvements in muscle mass and strength. WADA placed them on its monitoring list. They act via estrogen receptor beta to stimulate muscle protein synthesis.
Ecdysterone (beta-ecdysterone, 20-hydroxyecdysone) is a phytoecdysteroid studied for anabolic and ergogenic effects. A 2019 double-blind RCT found significant improvements in muscle mass and strength with ecdysterone supplementation. WADA has considered banning it. Evidence suggests it may act via estrogen receptor beta to stimulate muscle protein synthesis.
Whole eggs, consumed post-exercise, stimulate significantly greater muscle protein synthesis than egg whites alone despite identical protein content, due to bioactive compounds in the yolk. This enhanced anabolic response supports recovery and performance adaptation in resistance-trained individuals.
Electrolyte blends containing sodium, potassium, magnesium, and chloride are foundational to athletic performance by maintaining fluid balance, nerve conduction, and muscle function. Their role in hydration and performance during prolonged exercise is well-established in sports science literature and widely endorsed by authoritative sports nutrition bodies.
Ephedra (ma huang) contains ephedrine alkaloids that are potent stimulants with well-documented ergogenic effects on endurance, power, and weight loss. However, ephedra is banned in dietary supplements by the FDA (2004) due to serious cardiovascular safety risks. Its historical use as a performance enhancer is scientifically established.
Eurycoma longifolia (Tongkat Ali) is a Malaysian plant with traditional use as an ergogenic and testosterone-boosting herb. Multiple RCTs and systematic reviews show it can improve testosterone levels, muscle strength, body composition, and athletic performance at doses of 200–400 mg/day of standardized extract.
Multiple RCTs and a 2023 systematic review of six RCTs demonstrate that fenugreek supplementation significantly improves muscle strength, endurance, lean body mass, and reduces body fat percentage in resistance-trained individuals. Fenugreek glycosides (sapogenins and saponins) exhibit anabolic and androgenic activity, influencing testosterone levels. Evidence for glycogen resynthesis benefit during post-exercise recovery is mixed.
Fish oil omega-3s have documented effects on exercise recovery, particularly reducing delayed-onset muscle soreness (DOMS) in untrained individuals. A systematic review of 32 RCTs in athletes found consistent effects for fish oil on skeletal muscle recovery, cardiovascular dynamics in cyclists, and post-exercise nitric oxide responses. Effects on primary performance metrics (endurance, maximal strength) are not clearly established.
Clinical research on Aminogen®, a fungal protease blend derived from Aspergillus niger and Aspergillus oryzae, shows that co-ingestion with whey protein significantly increases postprandial plasma amino acid levels and nitrogen retention in active men. Enhanced amino acid bioavailability from supplemental protein is a mechanistic pathway relevant to training adaptations. Evidence is preliminary and product-specific rather than broadly generalizable to all fungal protease preparations.
Human RCTs on gamma oryzanol for athletic performance show conflicting results. A 1997 double-blind RCT found 500 mg/day for 9 weeks had no effect on strength, performance, or anabolic hormone levels. A 2014 double-blind RCT found 600 mg/day increased muscular strength in bench press and leg curl despite no anthropometric change. Evidence is inconsistent.
Clinical trials show garlic can improve aerobic capacity (VO2max) and lactate threshold in trained individuals, and attenuate exercise-induced oxidative stress and muscle damage markers. However, benefits for direct time-trial performance are inconsistent. Aged garlic extract (12 weeks, 2.56 g/day) improved VO2max and recovery in middle-aged endurance athletes. Garlic's ergogenic effects may be most relevant to cardiorespiratory fitness rather than raw power output.
Glucuronolactone is a naturally occurring compound from glucose metabolism commonly included in energy drinks alongside caffeine and taurine for athletic performance. While human-specific RCT evidence for glucuronolactone alone is limited, the combination with caffeine and taurine in energy drink RCTs shows consistent exercise performance improvements.
A 2008 human randomized study found that participants consuming standardized goji berry juice for 14 days reported significantly enhanced athletic performance and energy levels compared to controls. A meta-analysis of four RCTs confirmed improved athletic performance and reduced fatigue as outcomes. Preclinical research also documents anti-fatigue and endurance-enhancing effects.
Multiple human trials show GPC supplementation increases peak power output, isometric force, and neuromuscular performance. The proposed mechanism centers on elevated acetylcholine availability enhancing the neuromuscular signal for muscle contraction. Evidence is promising but limited by small sample sizes and mixed results at lower doses.
Clinical evidence from small RCTs indicates green tea extract (GTE) may reduce exercise-induced oxidative stress and muscle damage, supporting recovery in athletes. A triple-blind RCT in 16 trained male athletes supplementing with 500 mg/day GTE for 15 days showed preserved neuromuscular function and lower oxidative stress markers versus placebo. Fat oxidation enhancement with catechins plus caffeine has also been documented. Evidence is encouraging but based on small trials.
GLM supplementation has been studied in the context of exercise recovery, with one RCT (2023) showing significantly faster return of muscle force output (isometric and concentric peak torque) following eccentric exercise-induced damage in untrained men taking 3 g/day GSM powder. A separate RCT observed that mussel extract attenuated loss of leg muscle power following exhaustive running. Evidence pertains to recovery of performance capacity after damage rather than enhancement of baseline performance.
Multiple placebo-controlled human trials demonstrate guarana can reduce perceived exertion and improve cognitive performance during exercise. A crossover RCT in 25 participants found guarana (125 mg/kg) decreased choice reaction time before maximal cycling versus placebo. A 2023 systematic review and meta-analysis (8 studies, 328 participants) found a small but significant effect on response time (Hedge's g = 0.202, p = 0.005). Effects on shooting performance and perceived exertion have also been documented in high-level athletes.
Higenamine is a beta-2 adrenergic agonist alkaloid found in Nandina domestica and other plants, used in pre-workout supplements as a stimulant and bronchodilator for exercise performance. WADA banned it in 2017 as a prohibited substance due to its stimulant and potentially ergogenic properties.
HMB (beta-hydroxy-beta-methylbutyrate), a leucine metabolite, is recognized by the NIH ODS and ISSN for improving muscle protein synthesis, reducing muscle damage, and enhancing endurance capacity and lean mass. Most benefit is seen with doses of 3 g/day for at least 2 weeks before high-intensity exercise.
Honey functions as an effective carbohydrate source for athletes, with small RCTs demonstrating improved endurance performance compared to placebo. A systematic review (2018, ScienceDirect) identified three RCTs confirming that acute honey ingestion improved endurance performance in two of them. Its mixed fructose/glucose composition supports sustained carbohydrate oxidation during prolonged exercise.
Inosine is a purine nucleoside proposed as an ergogenic aid for improving energy availability in athletes. The EBSCO Research Starters sports performance database specifically addresses inosine, concluding that most available evidence suggests it does not work for athletic performance enhancement.
Iron is essential for oxygen transport via hemoglobin and myoglobin, and iron-deficiency anemia directly impairs aerobic exercise capacity. A systematic review found iron has among the strongest quality evidence for mineral supplementation in athletic performance. IV and oral iron supplementation in iron-deficient athletes improves aerobic capacity and reduces fatigue.
Isoleucine, as a BCAA, activates mTOR and AMPK pathways that support energy metabolism and anabolic signaling relevant to athletic performance. Systematic reviews of BCAA supplementation—within which isoleucine is a key component—show modest, mixed results on performance outcomes in athletes. Benefits on performance markers such as fatigue perception and strength are more consistently observed in resistance-trained populations than endurance athletes.
A randomized, double-blind, placebo-controlled crossover trial found that jiaogulan supplementation enhanced 20 km time-trial cycling performance in healthy males, associated with improved mitochondrial oxidative capacity and increased AMPK phosphorylation during exercise. Animal studies also show anti-fatigue effects via increased muscle and liver glycogen.
L-Alanyl-L-Glutamine is a dipeptide form of glutamine with improved stability and bioavailability. RCT evidence shows it can improve endurance performance and rehydration in athletes. It is more stable in solution than free glutamine, making it suitable for sports drinks.
L-arginine is the primary substrate for nitric oxide synthase, with theoretical benefits for vasodilation and exercise performance. Systematic reviews and RCTs show it can improve metabolic responses and select performance outcomes in high-intensity sports contexts, though direct performance enhancement evidence is mixed and dose/timing dependent.
L-carnitine facilitates transport of long-chain fatty acids into mitochondria for beta-oxidation, with theoretical ergogenic applications for fat utilization during exercise. Clinical studies show benefits primarily in populations with exercise intolerance or specific disease states, with mixed evidence in healthy athletes. It is a listed proposed ergogenic aid in authoritative sports nutrition literature.
Muscle carnosine acts as an intracellular pH buffer, delaying acid-induced fatigue during high-intensity exercise. Raising muscle carnosine via beta-alanine supplementation is among the best-supported ergogenic strategies in sports nutrition. Direct oral L-carnosine supplementation is less studied but shares the same mechanistic rationale.
L-Citrulline enhances arginine bioavailability and nitric oxide synthesis more effectively than L-arginine alone, improving blood flow and exercise performance. Multiple RCTs show it reduces muscle soreness and fatigue, and improves endurance and power output. NIH ODS includes it in its exercise/athletic performance fact sheet.
Clinical trials show L-glutamine supplementation attenuates post-exercise strength loss and muscle soreness, and may support mucosal immunity during intensive training. A 2018 systematic review and meta-analysis of 47 studies found a significant effect on body weight reduction but no consistent effect on VO2 max. Benefits appear most robust for recovery rather than peak performance output.
L-isoleucine, as one of the three BCAAs, is metabolized primarily in skeletal muscle and participates in muscle protein synthesis and recovery. Human RCTs with BCAA blends including isoleucine show modest reductions in exercise-induced muscle soreness and muscle damage markers. However, systematic reviews indicate BCAA supplementation does not reliably improve performance outcomes such as strength or endurance time when protein intake is already adequate.
L-Leucine is the primary BCAA for stimulating muscle protein synthesis via the mTOR pathway. Research confirms a threshold dose of ~2–3 g leucine is needed to maximally stimulate post-exercise MPS. NIH ODS and multiple sports nutrition authorities recognize leucine's role in muscle adaptation to resistance training.
Human RCTs show L-ornithine can improve measures of anaerobic performance and attenuate fatigue during exercise protocols, primarily through enhanced ammonia clearance. An RCT in 10 trained adults (Eur J Appl Physiol 2011) found significantly greater peak cycling RPM with L-ornithine. Another RCT (Nutrition Research 2008) documented reduced subjective fatigue and preserved physical output. However, not all studies show direct performance improvement; effects on maximal short-term power remain mixed.
Human trials have produced mixed results on L-Tryptophan's ergogenic effects. An early study found a 49% increase in treadmill run time to exhaustion, but subsequent trials at endurance intensities failed to replicate this. One double-blind crossover study found improved power output during mixed aerobic-anaerobic exercise.
L-Valine is a component of BCAA supplements that have demonstrated modest benefits for exercise performance in human trials. Valine competes with tryptophan for blood-brain barrier transport via the LAT1 transporter, potentially blunting central fatigue during prolonged activity. Most evidence comes from BCAA mixture trials rather than isolated valine studies. Effects are real but effect sizes are generally modest.
RCTs demonstrate that specific L. plantarum strains (PL-02, TWK10) improve endurance, muscle mass, explosive strength, and exercise performance. Benefits appear linked to enhanced glycogen storage, reduced muscle damage markers, and increased VO2max.
Oligomerized lychee fruit extract (OLFE) has been tested in human athletes for effects on high-intensity exercise performance. A pilot open-label trial in 10 male athletes showed improved power output during high-intensity intermittent exercise and modulation of exercise-induced reactive oxygen species after 7 days of OLFE supplementation. A separate double-blind RCT in 70 regularly exercising men found significant improvement in submaximal running time with OLFE vs. placebo.
Maca (Lepidium meyenii) is a Peruvian root vegetable with traditional Andean use for energy and endurance. RCT evidence in cyclists shows 14 days of maca supplementation improved time trial performance. It is listed by Examine.com among athletic performance supplements, though the evidence base is small.
Magnesium is involved in over 350 enzymatic reactions including ATP synthesis, muscle contraction, and protein synthesis. Athletes lose magnesium through sweat, and deficiency impairs performance. A systematic review identified magnesium as having among the strongest quality evidence for mineral supplementation in athletic performance.
A 6-week double-blind RCT in 48 amateur runners found NMN supplementation significantly improved aerobic capacity and skeletal muscle oxygen utilization. A multicenter RCT (Yi et al., GeroScience 2022) in middle-aged adults showed NMN at 600–900 mg/day increased 6-minute walking distance. A systematic review of 10 RCTs in 437 patients found non-significantly improved physical performance parameters.
Clinical evidence supports omega-3 fatty acids (EPA/DHA) for improving post-exercise recovery, reducing muscle damage markers, and modestly improving endurance. A 2026 meta-analysis of 41 RCTs found a statistically stable, clinically relevant role in reducing post-exercise inflammation and supporting functional recovery. Direct performance gains are modest (pooled SMD ~0.2), but reduced soreness and preserved function across training phases are meaningful benefits.
Ornithine alpha-ketoglutarate (OAK) is an amino acid-keto acid compound studied for anabolic properties, wound healing, and athletic recovery. The EBSCO Research Starters sports performance database lists it as a proposed ergogenic aid. Clinical evidence is strongest in clinical nutrition contexts; athletic performance RCT evidence is limited but supportive.
Pea protein supplementation combined with resistance training improves whole-body muscle strength comparably to whey protein. A 12-week RCT showed 16.1% improvement in whole-body muscle strength with pea protein. Evidence for acute performance benefits is less consistent.
Multiple clinical trials show peppermint essential oil ingestion can improve exercise performance, including time to exhaustion, grip force, VO2, and spirometry parameters. A 2023 European Journal of Nutrition RCT found runners supplementing with peppermint essential oil had a significantly greater time to exhaustion (109.9 min vs. 98.5 min; p=0.009, effect size 0.826). Menthol mouth rinsing has been studied as a non-thermal sensory cooling strategy in heat exercise but results for objective performance are mixed.
Phosphatidylserine is a phospholipid studied for blunting exercise-induced cortisol elevation and reducing DOMS, with potential to improve recovery and exercise capacity. The EBSCO Research Starters sports performance database lists it as a proposed ergogenic aid, and select RCTs show cortisol-attenuating effects that may benefit training adaptation.
Phosphate loading (typically sodium phosphate, ~3–4 g/day for 3–6 days) has been studied in multiple clinical trials as an ergogenic aid. Some trials demonstrate increases in VO2max and ventilatory anaerobic threshold; others show no significant benefit. Results are inconsistent overall.
Four RDP clinical trials show Pycnogenol (pine bark extract) enhances sports endurance, reduces muscle cramps and pain, and improves recovery in athletes. An RDP crossover study found significantly increased endurance time in recreational athletes. Mechanisms include improved oxygen delivery via enhanced microcirculation and antioxidant protection of muscle tissue.
Clinical trials show Pycnogenol improves physical fitness metrics and endurance in recreational athletes and triathletes. In two-part controlled studies, 100–150 mg/day over 4–8 weeks significantly improved run times, push-up and sit-up counts, and triathlon completion times. Mechanisms include antioxidant control of exercise-induced oxidative stress and improved microcirculation.
Bromelain has been studied in competitive athletes, with evidence from a double-blind RCT in cyclists showing reduction in muscle damage markers and inflammation. A combined anthocyanin-bromelain supplement improved endothelial function and skeletal muscle oxygenation in a double-blind crossover RCT.
Limited but existing clinical evidence suggests policosanol may modestly improve select performance metrics in trained athletes. A 2026 double-blind RCT in male taekwondo athletes found improvements in VOâ‚‚max and anaerobic power with 25 mg/day over 12 weeks. An earlier Cuban trial in coronary heart disease patients showed improved treadmill exercise capacity, though this was attributed to amelioration of myocardial ischemia rather than a direct ergogenic effect. Human evidence remains sparse and the effect size is modest.
Multiple RCTs and a systematic review (British Journal of Nutrition) indicate pomegranate supplementation may enhance endurance performance, reduce perceived exertion, and accelerate post-exercise recovery. A 2024 meta-analysis found significant improvements in oxidative stress markers, lactate, and blood pressure in athletes. Most benefit seen with ~250 ml juice or 250 mg extract daily for at least one week.
A 6-week double-blind RCT (n=23) in untrained men showed PQQ at 20 mg/day significantly elevated PGC-1α muscle protein (a marker of mitochondrial biogenesis) versus placebo but did not improve aerobic performance metrics beyond exercise training alone. Dedicated ergogenic effects are not confirmed.
Quercetin is a flavonoid with antioxidant and anti-inflammatory properties studied for improving aerobic exercise performance and reducing exercise-induced oxidative stress. A meta-analysis found quercetin supplementation produces a small but significant improvement in maximal oxygen uptake (VO2 max) and endurance performance.
Rhodiola rosea is an adaptogenic herb studied for reducing exercise-induced fatigue and improving physical performance and endurance. Clinical evidence shows it can reduce perceived exertion and time to exhaustion. It is listed as a proposed natural treatment for athletic performance in authoritative sports medicine references.
Robusta coffee's high caffeine content (~2.7% by bean weight) is an established ergogenic aid. Clinical crossover trials show caffeinated coffee at 5 mg caffeine/kg body weight improves endurance time-trial performance by ~5% versus placebo. Caffeine works by blocking adenosine receptors, reducing perceived exertion and delaying fatigue.
Schisandra has been studied for its potential to enhance physical stamina, endurance, and muscle strength. A randomized, double-blind, placebo-controlled trial in older women (n=52) found schisandra extract improved skeletal muscle strength. Soviet-era military research documented use for improving stamina and working capacity in healthy subjects.
Small but controlled human trials show schisandrin-standardized Schisandra extract improves muscle strength and reduces resting lactate. A 2020 double-blind RCT in adult women found 1,000 mg/day over 12 weeks significantly increased quadriceps strength and lowered resting lactate versus placebo. A multi-arm RCT in 215 elite athletes using schisandrin-containing adaptogen formulas reported improvements in fatigue scores and anabolic index versus placebo.
Sodium is lost in sweat during exercise and its replacement via electrolyte beverages is supported by clinical evidence as a strategy to prevent exercise-associated hyponatremia and maintain hydration during prolonged activity. Sodium bicarbonate supplementation has a separate but well-documented ergogenic role, improving performance in high-intensity efforts lasting 30 seconds to 12 minutes. Evidence for sodium salt tablets improving ultramarathon performance is, however, not supported by prospective data.
Two RCTs demonstrate that S. indicus extract (combined with Mangifera indica bark) significantly increases muscle strength, size, and endurance in healthy young men. The blend activates mTOR and enhances eNOS-mediated nitric oxide production. These are the strongest human data for this herb.
A 2025 PRISMA-compliant systematic review of RCTs confirmed that spinach extract supplementation, driven by its high nitrate content, improves physical performance parameters including muscle strength, endurance, and cycle time-trial outcomes. Nitric oxide generation from nitrate is the primary proposed mechanism.
A 2022 systematic review of 13 controlled trials found spirulina demonstrates ergogenic potential during submaximal exercise, increasing oxygen uptake and improving exercise tolerance. Spirulina's antioxidant content is hypothesized to reduce exercise-induced oxidative stress, with some studies showing increased fat oxidation during exercise. Evidence quality is modest; effects appear more consistent in athletes with suboptimal antioxidant dietary intake.
Synephrine is a sympathomimetic alkaloid from bitter orange (Citrus aurantium) that acts as an adrenergic stimulant. Multiple meta-analyses and systematic reviews support its thermogenic and performance-enhancing effects, particularly when combined with caffeine. It is used as a post-ephedra-ban substitute in sports supplements.
Taurine is a sulfur-containing amino acid studied for endurance exercise performance. A meta-analysis confirmed oral taurine improves endurance exercise capacity. RCT evidence in speed skaters showed significant improvements in anaerobic power outputs with acute dosing. Best taken ~60 minutes before exercise.
TMG (trimethylglycine), the chemical name for betaine, is included in the NIH ODS exercise and athletic performance fact sheet as a studied ergogenic supplement. Limited RCT evidence suggests it may enhance power output and work capacity, possibly through creatine synthesis upregulation and nitric oxide elevation.
Tongkat Ali (Eurycoma longifolia) is supported by multiple RCTs and systematic reviews for improving testosterone levels, muscle strength, lean body mass, and athletic performance at 200–400 mg/day of standardized extract. It is recognized by Examine.com among supplements for muscle gain and exercise performance.
Multiple clinical trials and systematic reviews have examined tribulus for athletic performance but found no consistent benefit. Human studies show no significant improvement in testosterone, lean mass, or strength with tribulus alone. The Australian Institute of Sport does not recommend it for athletes.
Turkesterone is an ecdysteroid found in Ajuga turkestanica studied for anabolic and ergogenic effects. It is proposed to stimulate muscle protein synthesis via estrogen receptor beta, similar to ecdysterone. While human RCT evidence is limited, it is among the most discussed phytoecdysteroids for athletic performance.
A double-blind, placebo-controlled trial in elite German Olympic athletes found that 300 mg/day of ubiquinol for 6 weeks significantly increased peak power output by +2.5% versus placebo. Ubiquinol's role in mitochondrial ATP production and its antioxidant protection against exercise-induced oxidative damage are the primary mechanisms. Evidence is modest but reproducible across multiple sports populations.
Multiple randomized controlled trials show Urolithin A (UA) improves aerobic capacity, muscle strength, and exercise performance in middle-aged and older adults. A 2025 RCT in competitive distance runners further demonstrated increased VO2max and reduced perceived exertion. Mechanistically, UA activates mitophagy, improving mitochondrial quality control in skeletal muscle.
Vanadyl sulfate has been tested in weight-training athletes in a double-blind, placebo-controlled RCT. The trial found no significant improvements in body composition and only a marginal, baseline-confounded difference in one leg-extension measure. Current evidence does not support a meaningful performance-enhancing effect.
Vigorous exercise may deplete riboflavin stores, elevating demand in active individuals. Studies suggest adequate riboflavin status is necessary to support the energy-producing metabolic pathways central to exercise. However, supplementation has not been shown to improve performance in already well-nourished athletes. One placebo-controlled trial in ultramarathon runners found high-dose riboflavin significantly reduced post-race muscle soreness.
Watermelon juice supplementation, rich in L-citrulline, has been shown in multiple RCTs to reduce perceived exertion, lower plasma lactate, and support aerobic capacity during exercise. Evidence exists from half-marathon and resistance training studies in athletes.
Whey protein is the most studied protein supplement for athletic performance and muscle adaptation. Post-exercise whey (20–30 g) rapidly stimulates muscle protein synthesis and shortens recovery time. RCT evidence across multiple sports confirms benefits for lean mass, strength, and performance when combined with training.
Multiple human clinical trials demonstrate that yerba mate increases fat oxidation during exercise and modestly improves time-trial performance. Its caffeine, theobromine, and polyphenol content contribute to these ergogenic effects. Evidence is strongest for endurance-type activities at moderate intensities. Overall evidence base is promising but trials are small.
Limited clinical evidence suggests yohimbine may modestly improve body composition in trained athletes, primarily via alpha-2 adrenergic blockade that enhances fat mobilization during exercise. A small RCT in elite soccer players found a significant reduction in body fat percentage over 21 days. Effects on direct performance metrics such as sprint speed or strength are inconsistent or absent. Evidence overall is limited and results are not uniform across studies.
Bee pollen has long been used by athletes as an ergogenic aid. Multiple clinical trials, however, found no statistically significant benefit on athletic performance metrics. The relationship is traditional in nature; animal studies show plausible mitochondrial and antioxidant mechanisms but human evidence is negative.
Eleuthero (Siberian ginseng, Eleutherococcus senticosus) has been used in traditional Chinese and Russian medicine to combat fatigue and improve endurance. The NIH ODS exercise fact sheet notes that while traditional use is documented, most rigorous clinical studies (five best-quality studies, n=79) showed no significant effect on exercise performance.
Ginkgo biloba has a long history in Traditional Chinese Medicine for improving vitality and circulation. Some research has explored its effects on exercise performance via improved blood flow and oxygen delivery, but clinical RCTs in athletic populations have produced inconsistent results. Evidence for athletic performance specifically is weak.
Ginseng (Panax species) has been used for millennia in Traditional Chinese Medicine to improve stamina and vitality. The NIH ODS notes that while preparations have been used traditionally to improve physical performance, most rigorous clinical trials have found no significant ergogenic effect on peak power, VO2, or time to exhaustion.
Improving muscle development and physical performance are among the historically documented uses of liver extract in medical literature. The preclinical evidence for AMPK activation, glycogen sparing, and lactate reduction provides a plausible mechanism, but human athletic performance trials using liquid liver fractions have not been published.
Suma (Pfaffia paniculata), known as 'Brazilian ginseng,' has traditional use in South America as an adaptogenic tonic for energy and endurance. Its proposed ergogenic compounds include ecdysteroids (beta-ecdysone) and pfaffosides. It is listed as a proposed ergogenic aid in the EBSCO Research Starters sports performance database.
Tribulus terrestris has been used in traditional Ayurvedic and Chinese medicine as a tonic claimed to boost testosterone and athletic performance. Multiple RCTs have failed to show significant increases in testosterone or direct athletic performance improvements in trained athletes, though traditional use is well-documented.
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