Energy

1,3-Dimethylamylamine (1,3-DMAA) is a synthetic stimulant widely used in pre-workout energy supplements. It acts as a sympathomimetic amine increasing CNS stimulation, energy, and exercise performance. The FDA has taken action against products containing 1,3-DMAA due to serious cardiovascular safety concerns, and it is banned in many jurisdictions.

Acetyl-L-carnitine (ALCAR) is a more bioavailable, acetylated form of L-carnitine that crosses the blood-brain barrier and supports both mitochondrial fatty acid oxidation and central nervous system energy metabolism. Clinical research supports its role in reducing fatigue and improving cognitive and physical energy, particularly in older adults and those with chronic fatigue conditions.

Alpha-ketoglutarate (AKG) is an intermediate in the TCA (Krebs) cycle and plays a central role in cellular energy production. It also serves as a nitrogen scavenger and is involved in amino acid synthesis. Emerging clinical evidence in older adults suggests AKG supplementation may support energy metabolism and reduce age-related metabolic decline.

Alpha-lipoic acid (ALA) is an endogenous mitochondrial coenzyme essential for pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase—key TCA cycle enzymes for ATP production. As both a cofactor and potent antioxidant, ALA protects mitochondria from oxidative damage. Clinical evidence supports its role in reducing fatigue, particularly in chronic fatigue syndrome and diabetic neuropathy.

D-ribose (alpha-D-ribofuranose) is a structural component of ATP and accelerates adenine nucleotide resynthesis via the pentose phosphate pathway. Two open-label clinical studies in CFS/fibromyalgia patients reported average energy increases of 45–61% on visual analog scales at doses of 15 g/day. Evidence in healthy populations is more limited and mixed.

Amylopectin is a high-glycemic-index carbohydrate that is rapidly digested to glucose, providing a fast-acting energy substrate for working muscles. Its rapid absorption makes it particularly relevant for replenishing muscle glycogen during or after prolonged exercise. Exercise nutrition research consistently identifies high-GI carbohydrates, including amylopectin-type starches, as the preferred fuel for immediate energy provision and glycogen resynthesis.

Ashwagandha (Withania somnifera) is a foundational Ayurvedic rasayana used traditionally to enhance vitality and reduce fatigue. Modern RCTs demonstrate that standardized root extract significantly reduces stress-related fatigue, improves subjective energy, and enhances physical endurance and VO2 max in adults.

Human RCTs have shown astaxanthin improves exercise endurance and reduces mental fatigue. A 2025 BMC Sports RCT found significantly longer time-to-exhaustion in the ASX group (28 mg/day, 4 days) during cycling. An 8-week trial reported a 36% reduction in mental fatigue. ASX may enhance mitochondrial fat oxidation, partially explaining improved energetic efficiency.

Adenosine 5'-triphosphate disodium is the supplemental form of ATP studied in clinical trials. At 400 mg/day, multiple double-blind RCTs show significant improvements in muscular strength, power, exercise capacity, and reduction in fatigue in trained adults. It acts via extracellular purinergic signaling to enhance blood flow and muscle excitability.

Bananas provide readily available carbohydrates (22–27 g per medium fruit), vitamin B6, and a range of electrolytes that support physical and cognitive energy. Multiple RCTs confirm banana carbohydrates sustain cycling performance comparably to commercial sports drinks over 75-km time trials. The carbohydrate-to-fiber ratio shifts with ripeness, affecting the rate of energy release.

Beetroot nitrate reduces the oxygen cost (VO₂) of submaximal exercise, effectively improving exercise economy and endurance capacity. Multiple RCTs and meta-analyses confirm improved time-to-exhaustion and exercise efficiency in recreationally active individuals. Benefits are smaller or absent in elite athletes.

Beta-alanine is the rate-limiting precursor to muscle carnosine, which buffers hydrogen ions during high-intensity exercise, delaying the onset of muscular fatigue and acidosis. Multiple RCTs and meta-analyses confirm that beta-alanine supplementation significantly increases exercise capacity and delays fatigue, particularly in activities lasting 1–4 minutes.

Black tea provides energy-promoting effects primarily via its caffeine content, which antagonizes adenosine receptors and reduces perceived fatigue. Clinical studies show improved alertness and reduced tiredness following black tea consumption. The combination of caffeine and L-theanine in tea modulates this stimulant effect.

Bovine heart provides CoQ10, L-carnitine, and B vitamins — three nutrients with documented roles in cellular ATP production. CoQ10 is an essential electron carrier in oxidative phosphorylation; L-carnitine transports fatty acids into mitochondria for beta-oxidation; B12 supports erythrocyte and neurological function. Constituent-level clinical evidence is robust, though bovine heart capsule-specific trials are absent.

Bovine kidney provides concentrated vitamin B12, riboflavin (B2), pantothenic acid (B5), and CoQ10—all recognized cofactors in energy-yielding metabolism. B vitamins and heme iron have EFSA-authorized health claims for reduction of fatigue. CoQ10 is an essential electron carrier in mitochondrial ATP synthesis. Deficiencies in these nutrients produce measurable fatigue.

Bovine liver delivers the full B-vitamin complex — B2, B3, B5, B6, B12, folate, and biotin — which are obligatory cofactors for cellular energy production via the TCA cycle and oxidative phosphorylation. Heme iron supports oxygen delivery to tissues. This combination addresses the primary nutritional underpinnings of cellular and systemic energy.

Caffeine is one of the most extensively studied ergogenic aids. It acts as an adenosine receptor antagonist, reducing perceived fatigue and enhancing alertness and physical performance. Meta-analyses confirm it improves exercise completion time by approximately 3.6% and significantly increases energy expenditure. It is widely recognized by sports nutrition bodies as an effective energy-boosting agent.

Caprylic acid is rapidly absorbed via the portal vein, bypassing lymphatic transport, and is efficiently converted to ketone bodies in liver mitochondria. Human crossover studies confirm C8 produces a significantly greater ketogenic (plasma beta-hydroxybutyrate) response than C10 or C12, providing a fast-acting alternative fuel source. This underpins its clinical use in fat-malabsorption syndromes and its popular use as an energy supplement.

MCTs in coconut milk are converted rapidly to energy in the liver or to ketone bodies, providing a faster-acting fuel source than long-chain dietary fats. This makes coconut milk a source of rapidly accessible energy, particularly relevant in low-glucose or ketogenic metabolic states.

Coenzyme A (CoA) is an essential cofactor in over 100 metabolic reactions, including the conversion of pyruvate to acetyl-CoA for TCA cycle entry and in fatty acid oxidation for energy production. It is biosynthesized from pantothenic acid (vitamin B5). CoA's direct role in cellular energy metabolism is scientifically well-established.

Copper is a structural component of cytochrome c oxidase (Complex IV), the terminal electron acceptor in the mitochondrial respiratory chain. Copper deficiency impairs oxidative phosphorylation and reduces cellular ATP production. This link is well-established biochemically and supported by human genetic disease models.

CoQ10 is an essential component of the mitochondrial electron transport chain and a lipid-soluble antioxidant. A systematic review and meta-analysis of 13 RCTs (n=1,126) found CoQ10 supplementation significantly reduced fatigue scores versus placebo. It is especially relevant for populations with low CoQ10 levels, including older adults and those with chronic fatigue syndrome.

Cordyceps (Cordyceps sinensis and C. militaris) has been used in Traditional Chinese Medicine as a tonic for energy, vitality, and endurance. Scientific studies show Cordyceps extracts can reduce fatigue biomarkers and improve aerobic exercise capacity, partly by enhancing ATP synthesis and oxygen utilization.

Creatine is a naturally occurring compound that donates phosphate groups to regenerate ATP during high-intensity exercise, directly supporting rapid energy production. Hundreds of RCTs confirm it enhances performance in short-duration, high-intensity tasks. The ISSN position stand classifies creatine monohydrate as the most effective ergogenic nutritional supplement for athletes.

Creatine monohydrate is among the most extensively validated ergogenic supplements for enhancing energy availability during high-intensity exercise. It increases intramuscular phosphocreatine stores, enabling faster ATP resynthesis during intense muscle contractions, and multiple systematic reviews confirm robust improvements in short-term high-intensity performance.

D-Ribose is a pentose sugar that is the structural backbone of ATP, ADP, and AMP. It is used clinically to replenish ATP in cardiac and skeletal muscle following ischemia or high-intensity exercise. Clinical studies show D-ribose supplementation significantly reduces fatigue and improves exercise tolerance in patients with heart failure, fibromyalgia, and chronic fatigue syndrome.

EGCG is the predominant catechin in green tea and contributes to its thermogenic and energy expenditure-enhancing effects. In combination with caffeine, EGCG has been shown in RCTs and meta-analyses to significantly increase resting energy expenditure and fat oxidation during exercise, making it a well-studied ingredient for energy metabolism support.

Ephedra (ma huang) contains ephedrine alkaloids that act as sympathomimetic amines, stimulating the CNS and increasing energy expenditure, thermogenesis, and alertness. It was historically used in Traditional Chinese Medicine and as a potent energy supplement. However, the FDA banned ephedrine alkaloid supplements in 2004 due to serious cardiovascular safety risks.

FMN is the prosthetic group of mitochondrial Complex I (NADH dehydrogenase), where it accepts electrons from NADH and initiates the electron transport chain to drive ATP synthesis. Adequate FMN/FAD status is therefore biochemically essential for cellular energy production. Riboflavin deficiency, which depletes FMN, results in fatigue and impaired energy metabolism, reversible upon repletion.

An 8-week double-blind RCT of Ganopoly (polysaccharide extract) in 132 neurasthenia patients showed significant reductions in the sense of fatigue and improved well-being versus placebo. A pilot RCT in breast cancer patients also demonstrated significant fatigue improvements with Ganoderma spore powder.

Panax ginseng has been used for over 2,000 years in Traditional Chinese Medicine to restore vitality and reduce fatigue. A systematic review and meta-analysis of RCTs found Panax ginseng compounds (PGC) were superior to placebo for fatigue outcomes, heart rate recovery, and clinical effect. It is recognized in European herbal monographs for tiredness and weakness.

Ginsenosides are the primary bioactive triterpenoid saponins of Panax ginseng, and are responsible for its energy-relevant effects. They modulate mitochondrial function, reduce blood lactate accumulation, and enhance antioxidant defense. Clinical and preclinical data support their role in reducing fatigue and improving physical performance.

Glucoamylase catalyzes the release of free glucose from oligosaccharides, directly enabling cellular uptake of the body's primary energy substrate. Without adequate glucoamylase activity, starch-derived glucose cannot be fully liberated for absorption and metabolic use.

Green tea contains caffeine and L-theanine as primary active constituents, both of which contribute to its energy and alertness-promoting effects. The combination of caffeine with L-theanine has been shown in RCTs to improve attention, mood, and energy while attenuating caffeine's jitter-inducing side effects. Green tea also increases energy expenditure via thermogenesis.

Guarana (Paullinia cupana) seeds contain approximately 2–4.5% caffeine, along with theobromine and theophylline, giving it stimulant and energy-boosting properties. Indigenous Amazonian peoples have long used guarana as a stimulant and energy food. A PMC meta-analysis found guarana significantly alleviated cancer-related fatigue in clinical trials.

Guaranine is the historical name for caffeine as isolated from guarana seeds (Paullinia cupana), where it exists in concentrations of 2–4.5%—among the highest in any plant. Its energy-relevant effects are identical to caffeine: adenosine receptor antagonism, reduced fatigue, and enhanced physical and mental performance. It is effectively synonymous with caffeine in the context of guarana-derived energy.

Invertase cleaves sucrose into glucose and fructose, the two monosaccharides that are absorbed in the small intestine and directly enter energy metabolism. Without adequate sucrase/invertase activity, sucrose cannot be converted to usable fuel. This enzymatic step is physiologically essential for deriving energy from sucrose-containing foods.

Iodine is an essential component of thyroid hormones T3 and T4, which regulate whole-body energy metabolism at the cellular level. Iodine deficiency leads to hypothyroidism, characterised by a markedly reduced metabolic rate and fatigue. Restoring adequate iodine intake in deficient individuals can normalise thyroid hormone levels and improve energy. The link is specifically to deficiency correction; evidence does not support energy enhancement in iodine-sufficient people.

Iron is a central component of hemoglobin, myoglobin, and cytochromes in the electron transport chain, making it essential for oxygen delivery and cellular ATP production. Iron deficiency anemia is one of the most common causes of fatigue worldwide. Supplementation corrects iron-deficiency fatigue and is supported by extensive clinical evidence.

Isoleucine is both glucogenic and ketogenic, meaning its catabolism feeds the TCA cycle to support cellular energy generation. During exercise and catabolic states, BCAAs including isoleucine are oxidized directly in muscle tissue to provide fuel. These mechanisms are established biochemically and supported by human metabolic data.

L-Alanine participates directly in energy metabolism by shuttling carbon skeletons from skeletal muscle to the liver, where they are converted to glucose via gluconeogenesis to sustain ATP production. This inter-organ energy transfer, known as the Cahill cycle, is well established in human physiology. Intravenous alanine infusion in 60-hour fasted humans was shown to markedly stimulate hepatic gluconeogenesis and oxidative flux.

L-asparagine contributes to cellular energy metabolism through its conversion to aspartate, which is an integral component of the malate-aspartate shuttle (MAS)—a key system linking glycolysis to mitochondrial oxidative phosphorylation and ATP production. Research shows that asparagine supplementation in cell models increases aspartate availability, activating the MAS and boosting respiratory capacity and TCA cycle flux. This is a biochemically established, peer-reviewed relationship, though human interventional evidence for L-asparagine supplementation increasing subjective or measured energy is absent.

L-carnitine is essential for transporting long-chain fatty acids across the inner mitochondrial membrane for beta-oxidation and ATP production. Clinical reviews and multiple RCTs demonstrate that L-carnitine supplementation reduces fatigue and improves physical performance, particularly in deficient or older populations.

L-isoleucine is a direct oxidative energy substrate, catabolized in skeletal muscle to acetyl-CoA and succinyl-CoA, which enter the TCA cycle to generate ATP. BCAA oxidation in muscle increases during prolonged exercise. Human cell studies using iPSC-derived myotubes confirm isoleucine's role in maintaining mitochondrial respiratory capacity and ATP production.

Leucine is a glucogenic and ketogenic amino acid; its catabolism in skeletal muscle and liver generates acetyl-CoA and acetoacetate, contributing to ATP production during prolonged exercise and fasting. BCOA dehydrogenase activity and leucine oxidation increase during endurance exercise, indicating leucine serves as an energy substrate when glycogen is limited.

L-ornithine has been shown to attenuate physical fatigue and improve energy-related outcomes by activating the urea cycle to clear ammonia and by promoting lipid oxidation via growth hormone stimulation. A double-blind crossover study (Sugino et al., Nutrition Research 2008) showed L-ornithine reduced subjective fatigue on the visual analog scale and improved physical performance in female subjects. The 2024 TSST RCT also confirmed that L-ornithine improved fatigue-inertia scores following social stress.

L-Theanine is an amino acid found almost exclusively in tea (Camellia sinensis) that promotes relaxed alertness and synergistically enhances the energy-boosting and cognitive effects of caffeine. Multiple RCTs show the caffeine+L-theanine combination significantly improves sustained attention, mental energy, and reaction time compared to either alone.

L-Valine is a glucogenic amino acid that can be converted to succinyl-CoA and enter the citric acid cycle, providing energy substrates during exercise and metabolic stress. Its branched-chain structure allows direct catabolism in skeletal muscle, bypassing hepatic processing. This metabolic role is well-established in human biochemistry and clinical nutrition.

Maca (Lepidium meyenii) has been cultivated and used by Andean indigenous peoples for centuries for energy, stamina, and endurance. Modern clinical and preclinical studies support improvements in exercise endurance and reduction of exercise-induced fatigue, and it is now classified as an adaptogen with evidence supporting anti-fatigue activity.

Magnesium plays a central role in ATP production and utilization: all ATP in cells exists as an Mg2+-ATP complex, and magnesium is a cofactor for over 300 enzymatic reactions including those in glycolysis and oxidative phosphorylation. EFSA authorizes health claims that magnesium contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue.

Matcha is a powdered form of green tea with higher concentrations of caffeine, L-theanine, and EGCG than standard green tea, providing synergistic energy, alertness, and cognitive enhancement effects. A double-blind crossover RCT found matcha significantly improved attention, psychomotor speed, and memory versus placebo. It has been used in Japanese Zen Buddhist practice for centuries to promote calm alertness during meditation.

MCTs are absorbed and oxidized more rapidly than long-chain fats, bypassing chylomicron formation and entering the liver directly via portal circulation for immediate beta-oxidation. This rapid metabolism produces acetyl-CoA and ketone bodies that serve as quick energy substrates. Human metabolic studies confirm elevated energy expenditure following MCT ingestion compared to LCT.

M. officinalis polysaccharides (MP-1, MP-2, MP-3) demonstrated antifatigue activity in weight-loaded swimming mouse models. Traditional TCM use of the root as a tonic to combat fatigue and enhance physical vitality is extensively documented across classical texts.

NADH (reduced nicotinamide adenine dinucleotide) is the principal electron donor in the mitochondrial electron transport chain and is directly involved in ATP synthesis. Supplemental NADH has been studied in RCTs for chronic fatigue syndrome, with some trials showing significant improvements in fatigue and energy levels.

Nicotinamide riboside (NR) is a form of vitamin B3 and a direct precursor to NAD+. Multiple human RCTs demonstrate that NR supplementation significantly elevates blood NAD+ levels, and emerging evidence shows improvements in energy metabolism and physical performance, particularly in older adults.

NMN is a direct precursor to NAD+, a coenzyme central to cellular energy metabolism. Clinical RCTs in older adults show NMN supplementation (150–1,200 mg/day) significantly increases blood NAD+ levels and improves physical performance markers. A systematic review of 10 RCTs found consistent improvements in physical performance parameters.

Phosphorus is an indispensable structural component of ATP, the universal cellular energy currency. Inorganic phosphate is required for oxidative phosphorylation in mitochondria and for glycolytic ATP synthesis. Deficiency (hypophosphatemia) rapidly impairs ATP production and causes clinical fatigue and muscle weakness.

Human evidence shows PQQ disodium salt increases the vigor subscale of the POMS-SF and improves urinary metabolite markers of mitochondrial TCA cycle activity, consistent with enhanced cellular energy metabolism. Mitochondrial biogenesis marker PGC-1α was significantly elevated in an exercise RCT.

Pyruvate is the end product of glycolysis and the central metabolite linking carbohydrate metabolism to mitochondrial energy production via the TCA cycle and oxidative phosphorylation. Supplemental pyruvate has been studied in multiple RCTs for effects on exercise capacity, fat oxidation, and energy endurance.

Human RCT data (Tang et al., 2005; n=132 neurasthenia patients) showed reishi polysaccharide extract significantly reduced fatigue and improved energy-related wellbeing versus placebo. A pilot RCT in breast cancer patients found reishi spore powder reduced cancer-related fatigue. Preclinical data indicate glycogen-sparing and antioxidant-mediated anti-fatigue mechanisms.

Rhodiola rosea (golden root) has an extensive history in traditional Scandinavian and Russian medicine as an adaptogen for reducing fatigue and enhancing physical and mental performance. Multiple RCTs and a systematic review of 11 controlled trials show it can significantly reduce mental and physical fatigue, with particular benefit in stress-induced exhaustion and burnout scenarios.

Robusta coffee's caffeine content—approximately twice that of arabica at ~2.7% by bean weight—acutely increases energy levels by antagonising adenosine receptors, thereby reducing central fatigue signals. Human trials confirm significant increases in energy expenditure, subjective energy, and alertness following caffeinated coffee consumption. Chlorogenic acids additionally support a more sustained glucose release, moderating the energy spike-and-crash cycle.

Schisandra has been used in TCM for millennia as a qi tonic to increase vitality and energy. In healthy subjects, schisandra generates alterations in nitric oxide and cortisol levels, supporting energy metabolism. It was formally listed in the official USSR medicine handbook as an energy-supporting adaptogen, and human trials show it increases endurance and working capacity.

Schisandrins are the primary bioactive lignans from Schisandra chinensis, a plant used in Traditional Chinese Medicine for centuries as a qi tonic and anti-fatigue adaptogen. Clinical and preclinical evidence supports schisandrins' ability to reduce exercise-induced fatigue, improve endurance, and protect mitochondrial function.

Spirulina is a cyanobacterium rich in protein, B vitamins (including B12 equivalent), iron, and phycocyanin, providing multiple substrates for energy metabolism. RCTs in athletes show spirulina supplementation improves exercise performance, delays fatigue onset, and reduces post-exercise oxidative stress. It is used traditionally in Africa and Mexico as an energy-rich food.

Succinic acid is a central intermediate of the mitochondrial TCA cycle, donating electrons directly to Complex II of the electron transport chain to drive ATP synthesis. Animal and in vitro studies confirm it sustains mitochondrial respiration and increases ATP production under metabolic stress. A 2026 systematic review of human exercise studies found mixed but suggestive evidence for improved oxygen uptake and aerobic performance.

Sulbutiamine is a synthetic lipophilic derivative of thiamine (vitamin B1) that crosses the blood-brain barrier more readily than thiamine. Clinical studies, including RCTs, show sulbutiamine reduces fatigue symptoms in patients with post-infectious asthenia and may improve subjective energy levels. It is approved in some countries as a fatigue-treating drug.

Taurine is a conditionally essential amino acid found at high concentrations in skeletal muscle, heart, and the brain. It is commonly included in commercial energy drinks and has been studied in multiple trials for its role in reducing oxidative stress during exercise and attenuating exercise-induced fatigue. Some RCTs show improved endurance performance with taurine supplementation.

Teacrine is the brand name (TeaCrine) for a nature-identical, standardized form of theacrine. Clinical safety and efficacy trials (6+ human RCTs) confirm its energy-promoting, fatigue-reducing effects via adenosine and dopamine receptor modulation, without habituation over 8 weeks of daily use up to 300 mg/day.

Theacrine is a purine alkaloid naturally occurring in kucha tea (Camellia assamica var. kucha), structurally similar to caffeine. A randomized, double-blind, crossover pilot RCT found 200 mg theacrine significantly increased energy (+8.6%) and reduced fatigue (−6.7%) versus placebo, without habituation. It acts via adenosine and dopamine receptor pathways.

Clinical trials in aging men and stressed adults consistently show Tongkat Ali reduces perceived fatigue and increases subjective energy levels alongside hormonal improvements. A multicentre RCT in aging males (Chinnappan et al., 2021, Food Nutr Res) found significant improvements in Aging Males' Symptoms scores including energy and fatigue. A systematic review confirmed TA improves quality of life and fatigue measures across multiple clinical designs. Traditional use as an energy tonic in Southeast Asia is well-documented.

As a rate-limiting electron carrier in the mitochondrial electron transport chain, ubiquinol is mechanistically central to cellular ATP (energy) production. Clinical trials in fatigue-prone populations, including ME/CFS and statin users, show measurable improvements in perceived energy and fatigue scores with CoQ10 supplementation. Its endogenous decline with age underpins growing use for age-related energy deficiency.

Vitamin B1 (thiamine) is an essential cofactor in energy metabolism, required for pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase—key enzymes converting carbohydrates to ATP via the citric acid cycle. Deficiency causes fatigue and impaired physical performance; European regulatory authorities have authorized a health claim that B1 contributes to normal energy-yielding metabolism.

Vitamin B12 (cobalamin) is essential for DNA synthesis, neurological function, and red blood cell formation. Deficiency causes megaloblastic anemia and severe fatigue; correction of B12 deficiency consistently restores energy. It also functions in mitochondrial energy metabolism. EFSA authorizes the health claim that B12 contributes to normal energy-yielding metabolism.

Vitamin B2 (riboflavin) is an essential precursor to FAD and FMN coenzymes, both of which are critical electron carriers in the mitochondrial respiratory chain and are required for oxidative phosphorylation and ATP production. EFSA has authorized the health claim that riboflavin contributes to normal energy-yielding metabolism.

Niacin (vitamin B3) is the precursor to NAD+ and NADP+, coenzymes essential for hundreds of metabolic reactions including glycolysis, the TCA cycle, and oxidative phosphorylation. Niacin deficiency (pellagra) causes profound fatigue. EFSA authorizes the health claim that niacin contributes to normal energy-yielding metabolism.

Niacinamide (nicotinamide), the amide form of vitamin B3, is also a direct precursor to NAD+ and functions identically to niacin in supporting energy metabolism. It is essential for ATP production through the electron transport chain and TCA cycle. EFSA authorizes its energy-yielding metabolism health claim.

Vitamin B5 (pantothenic acid) is an essential precursor to coenzyme A (CoA), which is required for the metabolism of carbohydrates, fats, and proteins into ATP. It plays an indispensable role in the TCA cycle via acetyl-CoA. EFSA authorizes the health claim that pantothenic acid contributes to normal energy-yielding metabolism.

Vitamin B6 (pyridoxine) is essential as pyridoxal-5'-phosphate (PLP) for over 100 enzymatic reactions including glycogen phosphorylase (crucial for muscle glycogen mobilization for energy) and amino acid metabolism. EFSA authorizes the health claim that B6 contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue.

Biotin (vitamin B7) is an essential coenzyme for carboxylase enzymes involved in fatty acid synthesis, gluconeogenesis, and amino acid catabolism—all central to energy homeostasis. EFSA authorizes the health claim that biotin contributes to normal energy-yielding metabolism. Deficiency impairs energy metabolism and causes fatigue.

Folate (vitamin B9) is essential for one-carbon metabolism, nucleotide synthesis, and mitochondrial function. Deficiency causes megaloblastic anemia and significant fatigue due to impaired red blood cell production and oxygen delivery. EFSA recognizes that folate contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue.

5-MTHF (methylfolate) is the biologically active form of folate, bypassing the need for enzymatic conversion and providing more direct support for one-carbon metabolism, mitochondrial function, and red blood cell production. It addresses folate-deficiency-related fatigue, particularly in those with MTHFR genetic variants who cannot efficiently convert folic acid.

Vitamin C (ascorbic acid) is an essential cofactor for carnitine biosynthesis (which is required for fatty acid transport into mitochondria for energy production) and for collagen synthesis supporting tissue oxygenation. It also functions as a free-radical scavenger protecting mitochondria. EFSA authorizes the health claim that vitamin C contributes to normal energy-yielding metabolism.

Vitamin D deficiency is independently associated with muscle fatigue, weakness, and reduced energy. Correction of low vitamin D levels has been shown in RCTs to significantly improve fatigue outcomes. Vitamin D receptors are present in muscle tissue, and vitamin D is involved in mitochondrial function and oxidative phosphorylation.

Yerba mate (Ilex paraguariensis) contains caffeine (mateine), theobromine, and theophylline, and has been used for centuries by South American indigenous cultures for energy and endurance. Clinical evidence confirms it increases energy expenditure, reduces fatigue, and improves exercise performance. It is one of the best-documented natural stimulant beverages.

Zinc is an essential trace element required as a cofactor for over 300 enzymes including lactate dehydrogenase and carbonic anhydrase, which are involved in cellular energy metabolism and pH regulation during exercise. EFSA authorizes the health claim that zinc contributes to normal energy-yielding metabolism. Deficiency causes fatigue and impaired physical performance.

Adrenal cortex extract has been marketed since the early 1900s for fatigue and low energy, rooted in the premise that cortisol—produced by the adrenal cortex—is central to energy metabolism. No rigorous clinical trial has confirmed that OTC adrenal cortex supplements improve energy in otherwise healthy adults. The theoretical basis involves supplying adrenal tissue nutrients to support cortisol synthesis.

Astragalus (Huang qi, Astragalus membranaceus) is one of the most important tonic herbs in Traditional Chinese Medicine, used for millennia to tonify wei qi (defensive energy) and enhance physical energy and vitality. Modern evidence shows astragalus polysaccharides and astragalosides support immune function and may have anti-fatigue effects in preclinical and some clinical settings.

Bee pollen is one of the most widely recognized traditional energy tonics and is extensively used by athletes for perceived energy and stamina. While its B-vitamin, carbohydrate, and protein content provide nutritional rationale, controlled clinical trials have failed to demonstrate objective performance or energy benefits.

Brown rice has a long history as an energy-providing staple food across Asian cultures, valued for its complex carbohydrates and B-vitamins supporting metabolic energy production. Brown rice protein retains B-vitamins (B1, B3, B6) that function as coenzymes in energy metabolism pathways. While no dedicated RCTs have tested brown rice protein isolate for subjective energy outcomes, its nutritional profile underpins its traditional and general nutritional use as an energy source.

Chlorella is a green microalgae used traditionally in Japan and East Asia as a nutritive tonic for energy, vitality, and detoxification. It provides a rich array of B vitamins, iron, magnesium, chlorophyll, and amino acids that support energy metabolism. Some small clinical studies show improvements in fatigue and aerobic exercise capacity with Chlorella supplementation.

Damiana has been used traditionally as a stimulant tonic to combat fatigue and boost vitality. It contains caffeine and volatile oils that may contribute to mild stimulant effects. Memorial Sloan Kettering notes limited evidence for stimulant effects. No controlled human studies specifically address energy outcomes.

Eleuthero (Eleutherococcus senticosus, Siberian ginseng) has been used for centuries in Traditional Chinese and Russian herbal medicine as an adaptogen to combat fatigue, enhance stamina, and improve overall vitality. Soviet researchers extensively promoted its use among athletes and cosmonauts. Scientific evidence for energy benefits is limited and inconsistent.

Goji berries (Lycium barbarum) have been used in Traditional Chinese Medicine for over 2,000 years as a tonic for energy, vitality, and longevity. A small randomized, placebo-controlled clinical trial found goji berry juice supplementation significantly improved energy levels, mood, and quality of life in healthy adults.

Jiaogulan has been used for centuries in southern China as a morning energy tonic, consumed as a tea to increase strength and endurance throughout the day. Its adaptogenic, AMPK-activating, and anti-fatigue properties provide a plausible pharmacological basis for this traditional use.

Liver has been used across many cultures as an energy-supporting food, and liver fractions carry this traditional reputation into supplement form. The B-vitamin complex (B2, B3, B5, B6, B12), CoQ10, and iron in liver fractions supports energy metabolism pathways, but no clinical trial has verified that supplemental liquid liver fractions meaningfully increase energy in healthy individuals.

Muira puama has a long-standing traditional role as an energy tonic and general vitalizer across Amazonian and European herbal medicine. A specially prepared root extract has been patented for its ability to relieve physical and mental fatigue. No rigorous human RCTs specifically targeting energy outcomes have been published.

Royal jelly has been used in traditional East Asian medicine as a general tonic to boost energy, vitality, and well-being. Clinical evidence is sparse and indirect; one RCT in stroke patients showed improvement in some physical parameters. No dedicated human RCT on energy or fatigue as a primary endpoint has demonstrated consistent significant effects.

Suma has a long tradition of use in South American indigenous medicine for increasing physical energy, vitality, and stamina. Known as 'para toda' (for everything), it is classified as an adaptogen believed to support the body's energy systems. One double-blind clinical study on the related species Pfaffia glomerata found no statistically significant benefit for physical performance in volunteers.

T. cordifolia is classified in Ayurveda as a Rasayana tonic and general vitality enhancer. The human adaptogenic trial showed improved physical performance and VO2 max, suggesting enhanced energy metabolism under stress. Traditionally, it is prescribed for general debility and fatigue.

Wheatgrass is widely used in traditional naturopathic practice as an energy tonic, attributed to its dense nutritional profile including B vitamins, iron, magnesium, and chlorophyll. Fatigue is listed as a traditional indication. No clinical trial has measured energy levels or fatigue scores with wheatgrass supplementation.

Increasing energy is the most widely cited traditional use of whole adrenal glandular, rooted in the supplement's role in naturopathic management of chronic low energy and 'adrenal fatigue.' WebMD, RxList, and integrative medicine sources consistently list energy support as the primary traditional application. No controlled clinical evidence supports this use for the modern, non-hormonal supplement form.

Brewer's yeast is traditionally used to combat tiredness and support energy, attributed to its dense content of B-complex vitamins (B1, B2, B3, B5, B6, B7, B9), which are essential cofactors in mitochondrial energy metabolism pathways. Fortified nutritional yeast is an excellent source of these vitamins. No dedicated human RCTs have tested brewer's yeast supplementation specifically for energy outcomes.

Traditionally, yohimbe bark was used in West African medicine as a tonic to reduce fatigue and enhance physical stamina, analogous in cultural context to ginseng. Modern use as an energy supplement is largely driven by its known stimulant properties via noradrenergic activation, but no dedicated clinical trials on energy or fatigue endpoints specifically have been identified in the literature.