IngredientesBeta-alanine (β-alanine) is a naturally occurring beta amino acid — one in which the amino group is attached to the β-carbon atom (the carbon atom two positions away from the carboxylate group) rather than the more usual α-carbon position. Its IUPAC name is 3-aminopropanoic acid. Unlike its counterpart α-alanine, β-alanine has no stereocenter, meaning it lacks chirality and exists as a single, non-enantiomeric form.
β-Alanine is the only naturally occurring β-type amino acid in nature and is also one of the very promising three-carbon platform compounds with applications in cosmetics, food additives, and as a precursor in the chemical, pharmaceutical, and material fields. It is widely used in medicine, food, and feed fields.
It is classified as a non-essential amino acid, produced by degradation of dihydrouracil and carnosine in vivo, and is not encoded in the genome of organisms for protein assembly. It is a component of the peptides carnosine and anserine, and also of pantothenic acid (vitamin B5), which itself is a component of coenzyme A.
Endogenous beta-alanine is produced in the liver primarily through the degradation of pyrimidines — notably via the uracil catabolism pathway. Additional sources for β-alanine include pyrimidine catabolism of cytosine and uracil. It is also formed by the degradation of dihydrouracil and carnosine.
Small amounts are also found in dietary sources — meat, poultry, and fish — as constituents of the dipeptides carnosine and anserine. Beta-alanine is naturally found in fish and animal proteins such as chicken, beef, and pork. It is not found in plants, so people who follow a vegan diet may have very low beta-alanine levels. Trace amounts can also be found in other animal products like eggs, milk, and cheese.
There are several functions of β-alanine unique to plants. It is accumulated as a generic stress response molecule involved in protecting plants from temperature extremes, hypoxia, drought, heavy metal shock, and some biotic stresses. The polyamines spermine/spermidine, propionate, and uracil have been shown to be precursors of β-alanine in plants.
Commercial supplement-grade beta-alanine is synthesized industrially (via decarboxylation of aspartate or reduction from fumaric/maleic derivatives) and purified to ≥98% purity by HPLC specifications. Beta-alanine can be synthesized through chemical and biological methods. The chemical synthesis method is relatively well-developed but requires extreme conditions including high temperature and pressure and strongly acidic and alkaline conditions; moreover, there are many by-products that require high energy consumption. Biological methods have the advantages of product specificity, mild conditions, and simple processes, making them more promising production methods.
Beta-alanine is available as a dietary supplement in various strengths and dosage forms. It is also added to many multi-ingredient products, including pre-workout supplements. Commercially, it is available in immediate-release powder and capsule forms, as well as sustained-release (SR) tablet formulations. To avoid paresthesia, a dose of 0.8–1.6 grams of beta-alanine every 3–4 hours is recommended. There are also sustained-release formulations available that permit the use of greater doses without the risk of paresthesia.
There is no documented record of isolated beta-alanine in traditional herbal medicine — it is not a botanical remedy but rather a physiological metabolite first exploited therapeutically in the evidence-based sports nutrition era.
Beta-alanine was first discovered in the early 20th century and was identified as a component of carnosine, a dipeptide found in muscle tissue. It was not until the 1990s that researchers began to investigate more seriously the potential benefits of beta-alanine supplementation for athletic performance.
It was only in the mid-2000s that pioneering work by Prof. Roger Harris and colleagues (2006) demonstrated that augmenting intracellular (within muscle) buffering was also possible via chronic (several weeks) beta-alanine supplementation, which significantly increased muscle carnosine and high-intensity performance. Since this time, there has been an explosion of research examining the efficacy of beta-alanine supplementation to optimally augment the muscle carnosine content and enhance subsequent performance.
The 2000s represented a turning point: supplemental beta-alanine, rather than dietary carnosine, was established as the most efficient method to achieve meaningful intramuscular carnosine loading. Because beta-alanine does not appear as an isolated herbal or botanical remedy in any ancient pharmacopeia, there is no documented traditional medical use of the isolated compound in Ayurveda, Traditional Chinese Medicine, or European herbalism. Its history is therefore primarily scientific and nutritional rather than ethnobotanical.
Carnosine (β-alanyl-L-histidine) is a naturally occurring dipeptide with numerous potential physiological functions, formed by combining its constituent amino acids, L-histidine and beta-alanine, with the assistance of the enzyme carnosine synthetase. Carnosine is present in high concentrations in human skeletal muscle (~20–30 mmol·kg−1 dry muscle).
Carnosine in muscle is synthesized by carnosine synthase, in which the plasma beta-alanine concentration is the rate-limiting substrate. The plasma concentration is less than 2 µM and the Km (concentration needed for a reaction rate that is 50% of maximum) for its uptake into muscle is approximately 1.0–2.3 mM. In contrast, L-histidine is present in much higher concentrations in plasma (50 µM) and muscle and has a much lower Km (16.8 µM).
Beta-alanine is the only rate-limiting precursor for carnosine synthesis — supplementing histidine does not increase muscle carnosine because histidine availability is not limiting.
Since the idea of beta-alanine supplementation is to elevate muscle carnosine levels, one might ask why carnosine itself is not supplemented. Carnosine is not absorbed very well in humans. When consumed, it is broken down into its respective amino acids (beta-alanine and histidine). When those amino acids enter a muscle cell, they join to form carnosine again. Thus, someone who supplements with carnosine would really just be using it as a beta-alanine source.
With respect to carnosine's structure, nitrogen atoms on the imidazole ring can readily accept a proton at physiological pH, and therefore it has been suggested that carnosine buffering precedes involvement of the bicarbonate buffering system during exercise. The pKa of the bicarbonate buffering system is 6.1, which is less than that of carnosine (pKa of 6.83), and thus a greater pH change is needed to elicit benefits from bicarbonate. Since the pKa of carnosine is closer to physiological pH, it is likely that this is utilized sooner as a buffer during high-intensity exercise.
The pKa of histidine's imidazole ring is 6.1. Yet when histidine binds to beta-alanine the pKa of the imidazole ring rises to 6.83 and has a major impact on H+ buffering. As a result of augmented muscle buffering and mitigating H+ accumulation, beta-alanine has been suggested to be most beneficial in activities limited by acidosis, generally ranging from 2 to 4 minutes.
Preliminary estimates of what contribution carnosine may play in buffering suggested as much as 40% of the buffering capacity of muscle when evaluated in animals; more recent research in humans has indicated the contribution may be as low as 7%. More evidence documenting the contribution of carnosine in muscle buffering is needed to further identify its role in exercise performance.
The purported roles of carnosine include proton buffering, anti-oxidation, anti-glycation, metal chelation, and influencing calcium sensitivity and hence muscle contractility. Carnosine may attenuate acidosis by acting as a pH buffer, but improved contractile performance may also be obtained by improved excitation-contraction coupling and defence against reactive oxygen species.
An interesting emerging mechanism is the carnosine shuttle hypothesis. Recent data in cardiac myocytes has demonstrated that carnosine is not just a buffer, but is also involved in Ca2+ and H+ handling from the sarcoplasmic reticulum as a type of "carnosine shuttle," though this requires confirmation in human skeletal muscle.
Decades of literature support a potential for carnosine to influence some mechanisms related to health including antioxidant properties, anti-aging, immune enhancing, and neurotransmitter actions. However, the majority of these health benefits have been explored in vitro and in animal models. Carnosine is widely considered an important anti-glycating agent that serves to prevent reactions that threaten to impact the structure and function of proteins in the body.
The enzyme aspartate 1-decarboxylase (L-aspartate 1-carboxy-lyase; EC 4.1.1.15), which catalyzes the conversion of aspartate to beta-alanine + CO2, was found in extracts of Escherichia coli. panD mutants of E. coli are defective in beta-alanine biosynthesis and lack aspartate 1-decarboxylase. Therefore, the enzyme functions in the biosynthesis of the beta-alanine moiety of pantothenate. In E. coli, beta-alanine is also a direct precursor in the biosynthesis of pantothenic acid (vitamin B5) and is crucial for biotechnological vitamin B5 production.
Even though much weaker than glycine (and, thus, with a debated role as a physiological transmitter), β-alanine is an agonist for strychnine-sensitive inhibitory glycine receptors (GlyRs), with the agonist order: glycine ≫ β-alanine > taurine ≫ alanine, L-serine > proline. This receptor activity is believed to underlie the well-known paresthesia side effect reported with supplementation.
This is the most extensively studied application of beta-alanine supplementation, with a substantial body of human randomized controlled trial (RCT) evidence and multiple systematic reviews and meta-analyses.
β-ALA supplementation (e.g., 2–6 grams/day) has been shown to increase carnosine concentrations in skeletal muscle by 20–80%. Several studies have reported that β-ALA supplementation can increase high-intensity intermittent exercise performance and/or training adaptations.
A 2012 meta-analysis found that β-alanine supplementation improves exercise capacity (P = 0.013), with beta-alanine showing a 'moderate' effect size compared to placebo. However, at that time the available data suggested that β-alanine supplementation had no benefit on measures of exercise performance rather than exercise capacity.
The International Society of Sports Nutrition (ISSN) 2015 position stand, a comprehensive critical review of evidence published through March 2015, arrived at the following key conclusions: Four weeks of beta-alanine supplementation (4–6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer; beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses; the only reported side effect is paraesthesia (tingling), but studies indicate this can be attenuated by using divided lower doses (1.6 g) or using a sustained-release formula; daily supplementation with 4 to 6 g of beta-alanine for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks/time trials lasting 1 to 4 min in duration; beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance; combining beta-alanine with other single or multi-ingredient supplements may be advantageous when supplementation of beta-alanine is high enough (4–6 g daily) and long enough (minimum 4 weeks); and more research is needed to determine the effects of beta-alanine on strength, endurance performance beyond 25 min in duration, and other health-related benefits associated with carnosine.
Since muscle acidosis is likely to contribute to the onset of fatigue during high-intensity exercise, increasing the muscle carnosine concentration would theoretically increase the intracellular buffering capacity, thereby potentially delaying the onset of fatigue.
A 2024 systematic review and meta-analysis in the International Journal of Sport Nutrition and Exercise Metabolism focused specifically on trained young males: Studies evaluating exercise performance through maximal or supramaximal intensity efforts falling within the 0.5–10 min duration were included. A total of 18 individual studies were analyzed, employing 18 exercise test protocols and 15 outcome measures in 331 participants.
A 2026 systematic review and meta-analysis assessed beta-alanine specifically in women: Twelve reports from 11 independent randomized controlled trials involving 312 women were included. Beta-alanine supplementation showed a pooled effect in favor of time to exhaustion (8 studies, N = 187; SMD = 0.49, 95% CI 0.20 to 0.79; p = 0.001; I2 = 0%). From a physiological perspective, this result may be plausible because the primary role of beta-alanine appears to relate more closely to intracellular buffering and fatigue attenuation, whereas VO2max and VO2peak are more strongly influenced by the upper limits of oxygen transport and utilization. A cautious interpretation is that the available evidence does not currently support a clear effect of beta-alanine on maximal aerobic capacity parameters in women.
Effect on repeated sprint ability: Chronic beta-alanine supplementation is a prevalent nutritional strategy to augment intracellular buffering capacity via elevated muscle carnosine. While its ergogenic efficacy in continuous, high-intensity exercise is established, its impact on repeated sprint ability — governed by extremely brief work bouts and phosphocreatine kinetics — remains equivocal.
Evidence strength: The evidence for beta-alanine improving time to exhaustion and exercise capacity during high-intensity efforts of 1–10 minutes is moderate to strong, supported by multiple RCTs and meta-analyses. Evidence for improvements in actual competitive performance (time trials, race outcomes) is weaker. Benefits for activities shorter than approximately 60 seconds are not established, as these are predominantly phosphocreatine-dependent and acidosis is not the primary limiting factor.
Both beta-alanine (via carnosine) and sodium bicarbonate target exercise-induced acidosis through complementary intracellular and extracellular mechanisms, respectively. It has been suggested that chronic beta-alanine supplementation improves high-intensity exercise performance by increasing muscle carnosine content, thereby enhancing intracellular proton buffering. Excess protons are also buffered independently of carnosine by a number of physicochemical buffering constituents; extracellular bicarbonate is the most relevant for increasing muscle buffering capacity, thereby acting to maintain intramuscular pH.
A 2024 systematic review and meta-analysis examining combined supplementation found: Ten studies totalling 243 individuals met the criteria with 12 outcomes for each nutritional supplement. No ergogenic effect was detected in this meta-analysis for beta-alanine alone (SMD = 0.18, 95% CI: −0.06; 0.43, p = 0.13) or sodium bicarbonate alone in isolation. Collectively, the body of literature suggests a modest additive effect when adding sodium bicarbonate to beta-alanine supplementation in exercise bouts in which metabolic acidosis may be performance-limiting. While this additive benefit is not typically revealed with traditional statistical analyses, studies using magnitude-based inferences have suggested that a modest additive effect is likely to exist.
Previous studies have suggested that beta-alanine supplementation may benefit exercise performance, but current evidence regarding its effects on body composition remains unclear. Pooled effect size from 20 studies indicated that beta-alanine supplementation has no effect on body mass (WMD: −0.15 kg; 95% CI: −0.78 to 0.47; p = 0.631) or fat mass (WMD: −0.24 kg; 95% CI: −1.16 to 0.68; p = 0.612).
It has been hypothesized that beta-alanine supplementation could lead to improvements in lean mass by increasing the volume of training, although evidence is equivocal. For instance, beta-alanine supplementation increased lean mass after 3 weeks of HIIT in recreationally active college-aged men. On the other hand, Kern et al. did not report changes in body composition or lean mass after beta-alanine supplementation for 8 weeks in previously trained athletes.
Evidence strength: Based on pooled data from 20 RCTs, there is currently no evidence that beta-alanine supplementation directly alters body mass, fat mass, or lean mass. Evidence is weak and inconsistent.
Ageing is associated with a significant reduction in skeletal muscle carnosine, which has been linked with a reduction in the buffering capacity of muscle and in theory, may increase the rate of fatigue during exercise.
A double-blind, placebo-controlled study (Stout et al., 2008) investigated beta-alanine supplementation in elderly subjects: Twenty-six men (n=9) and women (n=17) (mean age 72.8 ± 11.1 years) were randomly assigned to either beta-alanine (800 mg × 3 per day; CarnoSyn™) or placebo group. Before and after the supplementation period, participants performed a discontinuous cycle ergometry test to determine the physical working capacity at the fatigue threshold (PWCFT). Significant increases in PWCFT (28.6%) from pre- to post-supplementation were found for the beta-alanine treatment group (p < 0.05), but no change was observed with placebo. These findings suggest that ninety days of beta-alanine supplementation may increase physical working capacity by delaying the onset of neuromuscular fatigue in elderly men and women.
A subsequent study (Stegen et al.) investigated elderly subjects aged 60–80 years: Eighteen healthy elderly subjects (60–80 years, 10 female and 4 male) were randomly assigned to receive either beta-alanine (n = 12) or placebo (n = 6) for 12 weeks. The beta-alanine group received 3.2 g per day (2 × 800 mg sustained-release CarnoSyn™ tablets, given 2 times per day). Changes in time-limited and time-to-exhaustion tests were positively correlated to the changes in muscle carnosine.
Evidence strength: Preliminary to moderate. Human studies suggest beta-alanine can attenuate neuromuscular fatigue in older populations, likely via carnosine-mediated buffering, with effect sizes potentially more pronounced than in younger adults. Sample sizes in existing studies are small, and replication is limited.
Animal investigations have demonstrated that β-alanine can cross the blood–brain barrier and increase carnosine content in all brain regions in both young and older rats. Elevations in brain carnosine were associated with maintaining brain-derived neurotrophic factor (BDNF) expression during both fear and blast exposure stressors. Animals provided with β-alanine experienced reduced brain inflammation, reduced anxiety, and maintained spatial memory compared to animals exposed to these stimuli but given a placebo. These studies suggested that β-alanine supplementation could impact neural tissue and potentially promote brain health.
A double-blind RCT (Ostfeld et al., 2023) investigated cognitive effects in older humans: This study investigated 10 weeks of β-alanine (BA) supplementation on changes in cognitive function, mood, and physical performance in 100 older adults (mean age 70.6 ± 8.7 years). Participants were randomized into a BA (2.4 g·d−1) or placebo group. Testing occurred prior to supplementation, at the midpoint, and at week 10. Participants completed cognitive function assessments, including the Montreal Cognitive Assessment (MoCA) and the Stroop pattern recognition test, at each testing session. Behavioral questionnaires and physical function assessments (grip strength and timed sit-to-stand) were also conducted.
No difference between groups was noted in MoCA scores overall (p = 0.19). However, when examining participants whose MoCA scores at baseline were at or below normal (i.e., ≤26), participants in beta-alanine experienced significant improvements in MoCA scores at mid-point (13.6%, p = 0.009) and a significant interaction was found (F= 3.37, p = 0.042). Post-hoc analysis revealed that MoCA scores were significantly greater for beta-alanine than for placebo at both mid-point (p = 0.009) and post-intervention (p = 0.016).
A related pilot study examined brain morphology: This study examined the effects of 10 weeks of beta-alanine supplementation on changes in circulating brain inflammatory markers, brain-derived neurotrophic factor (BDNF), and brain morphology. Twenty participants were initially randomized into beta-alanine (2.4 g·d−1) or placebo groups. At each testing session, participants provided a resting blood sample and completed the MoCA test and magnetic resonance imaging, which included diffusion tensor imaging to assess brain tissue integrity.
Evidence strength: Preliminary in humans; animal data are more extensive. The cognitive signal in humans appears confined to individuals with already-compromised baseline cognitive function, and sample sizes are small. This area requires substantially more large-scale RCTs before firm conclusions can be drawn.
Carnosine's purported roles include anti-oxidation, anti-glycation, and metal chelation. Carnosine is widely considered an important anti-glycating agent that serves to prevent reactions that threaten to impact the structure and function of proteins in the body. Decades of literature support a potential for carnosine to influence mechanisms related to health including antioxidant properties, anti-aging, immune-enhancing, and neurotransmitter actions. However, the majority of these health benefits have been explored in vitro and in animal models.
Evidence strength: Largely preclinical (in vitro and animal). The degree to which beta-alanine supplementation — via increasing carnosine — translates these antioxidant and anti-glycation properties into meaningful human health outcomes remains unestablished. Human RCT evidence is very limited in this area.
A 2023 systematic review examined beta-alanine supplementation across combat sports: The search was carried out in SCOPUS, Web of Science, and Medline (PubMed) databases for studies published until July 31, 2023. Of the 41 registers identified, only 7 met the established criteria and were included. Overall, performance parameters related to strength, power, total exercise work capacity, and combat-specific parameters were significantly improved (p < 0.05). Perception parameters increased non-significantly (p > 0.05).
Evidence strength: Preliminary; based on a small number of RCTs with heterogeneous methods and outcomes. Results are directionally positive for work-capacity-related parameters.
High carnosine concentrations are found in individuals with a high proportion of fast-twitch fibres, because these fibres are enriched with the dipeptide. Muscle carnosine content is lower in women, declines with age, and is probably lower in vegetarians, whose diets are deprived of beta-alanine.
A study investigating 149 healthy subjects found that men have 36–82% higher carnosine concentrations than women across different muscle groups. The carnosine content of the soleus muscle is negatively related to the subjects' age. Vegetarians have a lower carnosine content of 26% in gastrocnemius compared to omnivores.
In vegetarians, muscle carnosine is limited by hepatic synthesis of β-alanine, whereas in omnivores this is augmented by the hydrolysis of dietary histidine-containing dipeptides, resulting in muscle levels two or more times higher.
Women have previously been reported to have lower muscle carnosine than men, which may be due to factors such as gender dimorphism in sex steroid concentrations or variation in fiber-type composition. Despite these differences, data indicate that both men and women have a similar response to beta-alanine supplementation, indicating that the lower values previously reported in women are unlikely to relate to an inherent gender dysmorphism in the biological factors that underpin carnosine metabolism.
Following the cessation of supplementation, muscle carnosine returns to pre-supplementation levels, with an estimated half-life of 5–9 weeks. Muscle carnosine washout after stopping supplementation takes 4–8 weeks (half-life), meaning ergogenic benefits persist well after discontinuation.
The following dosages are drawn directly from published studies and the ISSN position stand:
Paresthesia is the only known side effect, caused by acute plasma elevation of beta-alanine after a single dose. This effect can be decreased through dividing the total daily dose throughout the day. The most well-known and substantiated side effect is paresthesia, which has a good chance of becoming bothersome at doses above 40 milligrams per kilogram of body weight.
The exact underlying molecular mechanisms of paresthesia remain elusive, although activation of strychnine-sensitive glycine receptor sites associated with glutamate-sensitive N-methyl-D-aspartate receptors in the central nervous system has been proposed.
Taking very high doses of beta-alanine may increase the risk of having a tingling, prickling, or burning sensation in different parts of the body. Although this feeling may be uncomfortable, it is not harmful and will go away on its own. Splitting beta-alanine into two to three separate doses taken at different times of the day can help reduce the risk of this happening.
Less common side effects are gastrointestinal issues, which are often preventable by taking the supplement with food.
Beta-alanine and taurine share the same transporter (Tau-T) into skeletal muscle, with beta-alanine thereby inhibiting taurine uptake within the muscle. In animal models, beta-alanine has been shown to decrease circulating taurine levels by about 50%. Harris et al. reported that 4 weeks of beta-alanine supplementation (10–40 mg·kg−1bw) resulted in an increase in plasma taurine concentration; however, there was no significant decrease in muscle taurine content. While taurine has a number of essential physiological functions, to date there is no human data to support decreases with beta-alanine supplementation.
In one study examining a sustained-release formulation at 15 g/day for 30 days, there were statistically significant increases in serum triglycerides, LDL-cholesterol, and urea nitrogen at the end of the study as compared with baseline, although there were no differences with the control group. More studies are required to evaluate the changes in blood parameters that can be caused by high intake of β-alanine during a long period of time.
There is a need for long-term safety data on beta-alanine supplementation as well as more information on potential benefits in special populations such as the elderly and tactical athletes. Most studies focus on short supplementation cycles, leaving the long-term safety profile unknown. Chronic, high-dose users may face potential risks that have yet to be identified or thoroughly investigated. The International Society of Sports Nutrition acknowledges this gap in their position stand on beta-alanine.
Beta-alanine is generally safe and well tolerated, but there is little reliable data concerning its safety in pregnancy and lactation. Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses.
According to the 2026 WADA List of Prohibited Substances, beta-alanine is not prohibited.
Condiciones de salud que beta-alanina puede ayudar a apoyar.
BA is the rate-limiting precursor to carnosine, which is a well-characterized endogenous antioxidant that scavenges reactive oxygen species (ROS), chelates pro-oxidant metal ions, and quenches reactive aldehydes such as 4-hydroxynonenal (HNE) and acrolein generated during lipid peroxidation. COPD patients with deficient muscle carnosine exhibit elevated oxidative/carbonyl stress, and carnosine's antioxidant activity has been confirmed in multiple tissue models including skeletal muscle, cardiac muscle, and brain.
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.
Carnosine (synthesized from BA) and BA itself have been associated with improved glycemic control in meta-analyses of human RCTs, with reductions in fasting blood glucose and HbA1c in people with prediabetes or type 2 diabetes. A 2025 meta-analysis (8 RCTs, n=377) reported significant reductions in fasting blood glucose (SMD: −0.53) and HbA1c (SMD: −0.36) vs. placebo. Most human effect is primarily attributed to carnosine supplementation, with limited direct BA-only human data.
BA and its downstream product carnosine support cellular energy homeostasis through multiple mechanisms: pH buffering that preserves the efficiency of glycolysis and ATP regeneration during high-intensity work, and direct upregulation of mitochondrial biogenesis markers. In vitro, BA treatment of skeletal muscle cells significantly increased PGC-1α, TFAM, and oxygen consumption, indicating enhanced oxidative metabolism. Carnosine also preserves mitochondrial ATP production in energy-stressed cells.
BA supplementation delays the onset of neuromuscular fatigue by elevating muscle carnosine and buffering exercise-induced acidosis, allowing sustained effort before subjective and biochemical fatigue thresholds are reached. RCTs have demonstrated significant increases in the physical working capacity at fatigue threshold (PWCFT) and time-to-exhaustion in both younger and older populations. Effects are exercise-context specific rather than addressing systemic chronic fatigue syndrome.
Carnosine levels are markedly reduced in aging brains and in Alzheimer's disease. A systematic review with meta-analysis of 5 clinical studies found that carnosine/anserine supplementation (1 g/day for 12 weeks) improved global cognitive function in elderly subjects and those with mild cognitive impairment. BA, as the rate-limiting precursor to carnosine, represents an indirect means to support this pathway, with direct RCT evidence in older adults showing cognitive improvements particularly in those with below-normal baseline function.
Patients with COPD have significantly lower skeletal muscle carnosine levels and suffer from elevated exercise-induced acidosis and oxidative stress, creating a mechanistic rationale for BA supplementation. A 12-week double-blind RCT (n=40, 3.2 g/day) confirmed that BA significantly increases muscle carnosine in COPD patients, though improvements in exercise capacity and quadriceps function did not reach statistical significance in this stable cohort. Ongoing larger trials (BASE-TRAIN, BASE-ELECTRIC; n=222) are testing BA as an adjunct to pulmonary rehabilitation.
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.
Limited RCT evidence in middle-aged and older adults suggests BA supplementation may attenuate post-exercise declines in executive function. In a 28-day RCT in adults aged ~60, BA (2.4 g/day) prevented the post-fatigue decline in Stroop test performance seen in the placebo group. A 10-week RCT in 100 older adults (2.4 g/day) found improved cognitive function assessed by MOCA and Stroop tests, particularly in those with borderline or below-normal baseline cognition. Effects may be mediated by increased brain carnosine and anti-inflammatory/antioxidant activity.
Muscle carnosine levels decline with age and are inversely correlated with the onset of sarcopenia. BA supplementation in elderly subjects (60–80 years) has been shown to significantly increase muscle carnosine and improve exercise capacity. Multiple RCTs in older adults have used 1.6–3.2 g/day BA over 28–90 days and demonstrated reductions in neuromuscular fatigue and improvements in physical working capacity, supporting a role in countering age-related muscle decline.
Meta-analytic evidence from human RCTs shows that carnosine or BA supplementation reduces HOMA-IR (a marker of insulin resistance) and fasting insulin, suggesting improved insulin sensitivity in people with impaired glucose metabolism. The 2021 Advances in Nutrition meta-analysis found a reduction in HOMA-IR (SMD: −0.41) and fasting insulin (SMD: −0.41) in humans. Mechanistic pathways involve anti-glycation, reduction of oxidative stress in insulin-sensitive tissues, and GLUT4 upregulation.
Beta-alanine is the rate-limiting precursor to muscle carnosine synthesis, and supplementation consistently increases muscle carnosine by 40–80% after 4–10 weeks. Elevated carnosine buffers intramuscular acidosis during high-intensity exercise, reducing fatigue and metabolic disturbance requiring recovery between bouts.
Beta-alanine (BA) raises intramuscular carnosine, a dipeptide that buffers hydrogen ions produced during high-intensity exercise, directly delaying the onset of muscular acidosis and fatigue. A 2012 systematic review of 23 RCTs confirmed improvements in perceived exertion and biochemical markers of muscle fatigue at a mean dose of ~4.8 g/day over ~5 weeks. Effects are most pronounced for exercise bouts lasting 1–4 minutes. Performance improvements in total work or time-to-exhaustion are more modest and less consistent across studies.
Beta-alanine is one of the best-documented ergogenic aids for physical endurance, recognized by the IOC. It elevates intramuscular carnosine, buffering acid during high-intensity exercise and delaying fatigue. Multiple meta-analyses confirm improvements in time to exhaustion and muscular endurance at daily doses of 4–6.4 g. A 2025 systematic review confirmed it improves time to exhaustion in female athletes.
Sistemas corporales que beta-alanina puede ayudar a apoyar.
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