PMID 27797728 β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis Meta-analysis · Br J Sports Med, 2017 40 studies, 1,461 people - overall effect size 0.18 (small), but exercise duration moderated it; capacity effect size about 0.50 in the 0.5–10 min window.
Key summary
An independent meta-analysisA statistical synthesis combining results of multiple studies into one conclusion. of beta-alanine on exercise capacity and performance (40 double-blind, placeboAn inert dummy treatment used as the comparison baseline.-controlled studies, 65 exercise protocols, 1,461 people). The overall effect size was small at 0.18, but meta-regression showed exercise duration significantly moderated the effect (p=0.004), and within the 0.5–10 min window exercise capacity (effect size about 0.50) benefited more than performance (about 0.11). Training status, intermittent versus continuous exercise, and total dose were unrelated to the effect. Co-supplementation with sodium bicarbonate gave the largest effect. The data help individuals judge the likelihood of a benefit by exercise type.
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OBJECTIVE: To conduct a systematic review and meta-analysis of the evidence on the effects of β-alanine supplementation on exercise capacity and performance. DESIGN: This study was designed in accordance with PRISMA guidelines. A 3-level mixed effects model was employed to model effect sizes and account for dependencies within data. DATA SOURCES: 3 databases (PubMed, Google Scholar, Web of Science) were searched using a number of terms ('β-alanine' and 'Beta-alanine' combined with 'supplementation', 'exercise', 'training', 'athlete', 'performance' and 'carnosine'). ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Inclusion/exclusion criteria limited articles to double-blinded, placebo-controlled studies investigating the effects of β-alanine supplementation on an exercise measure. All healthy participant populations were considered, while supplementation protocols were restricted to chronic ingestion. Cross-over designs were excluded due to the long washout period for skeletal muscle carnosine following supplementation. A single outcome measure was extracted for each exercise protocol and converted to effect sizes for meta-analyses. RESULTS: 40 individual studies employing 65 different exercise protocols and totalling 70 exercise measures in 1461 participants were included in the analyses. A significant overall effect size of 0.18 (95% CI 0.08 to 0.28) was shown. Meta-regression demonstrated that exercise duration significantly (p=0.004) moderated effect sizes. Subgroup analyses also identified the type of exercise as a significant (p=0.013) moderator of effect sizes within an exercise time frame of 0.5-10 min with greater effect sizes for exercise capacity (0.4998 (95% CI 0.246 to 0.753)) versus performance (0.1078 (95% CI -0.201 to 0.416)). There was no moderating effect of training status (p=0.559), intermittent or continuous exercise (p=0.436) or total amount of β-alanine ingested (p=0.438). Co-supplementation with sodium bicarbonate resulted in the largest effect size when compared with placebo (0.43 (95% CI 0.22 to 0.64)). SUMMARY/CONCLUSIONS: β-alanine had a significant overall effect while subgroup analyses revealed a number of modifying factors. These data allow individuals to make informed decisions as to the likelihood of an ergogenic effect with β-alanine supplementation based on their chosen exercise modality. ※ The abstract text as collected and stored via the API by the pipeline. The key summary is written based solely on this text.
View original ↗ PMID 39032921 Effect of Beta-Alanine Supplementation on Maximal Intensity Exercise in Trained Young Male Individuals: A Systematic Review and Meta-Analysis Meta-analysis · Int J Sport Nutr Exerc Metab, 2024 18 trials, 331 trained young men - effect size 0.39 for 0.5–10 min maximal exercise, most pronounced at 4–10 min and 5.6–6.4 g/day.
Key summary
An independent meta-analysisA statistical synthesis combining results of multiple studies into one conclusion. of chronic beta-alanine on maximal-intensity exercise of 0.5–10 min in trained men aged 18–40 (18 randomized, double-blind, placeboAn inert dummy treatment used as the comparison baseline.-controlled trials, 331 people). The overall effect size versus placebo was significant at 0.39 (p=0.01), with significant benefits at 4 weeks of supplementation (0.34), for 4–10 min maximal efforts (0.55), and at a high dose of 5.6–6.4 g/day (0.35). It informs which exercise modality, dose, and duration provide the greatest ergogenic effect.
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Beta-alanine is a nonessential amino acid that is commonly used to improve exercise performance. It could influence the buffering of hydrogen ions produced during intense exercise and delay fatigue, providing a substrate for increased synthesis of intramuscular carnosine. This systematic review evaluates the effects of beta-alanine supplementation on maximal intensity exercise in trained, young, male individuals. Six databases were searched on August 10, 2023, to identify randomized, double-blinded, placebo-controlled trials investigating the effect of chronic beta-alanine supplementation in trained male individuals with an age range of 18-40 years. 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 significant (p = .01) result was observed with an overall effect size of 0.39 (95% confidence interval [CI] [0.09, 0.69]), in favor of beta-alanine supplementation versus placebo. Results indicate significant effects at 4 weeks of supplementation, effect size 0.34 (95% CI [0.02, 0.67], p = .04); 4-10 min of maximal effort, effect size 0.55 (95% CI [0.07, 1.04], p = .03); and a high beta-alanine dosage of 5.6-6.4 g per day, effect size 0.35 (95% CI [0.09, 0.62], p = .009). The results provide insights into which exercise modality will benefit the most, and which dosage protocols and durations stand to provide the greatest ergogenic effects. This may be used to inform further research, and professional or recreational training design, and optimization of supplementation strategies. ※ The abstract text as collected and stored via the API by the pipeline. The key summary is written based solely on this text.
View original ↗ PMID 22270875 Effects of β-alanine supplementation on exercise performance: a meta-analysis Meta-analysis · Amino Acids, 2012 15 studies, 360 people - exercise of 60–240 s improved (P=0.001); no benefit under 60 s (P=0.312). Duration is the key.
Key summary
An early quantitative meta-analysisA statistical synthesis combining results of multiple studies into one conclusion. of beta-alanine on exercise performance (15 manuscripts, 23 exercise tests, 360 people). The beta-alanine group improved exercise outcomes more than placeboAn inert dummy treatment used as the comparison baseline. (P=0.002), a benefit driven mainly by improved exercise capacity. Consistent with carnosine's acid-buffering mechanism, exercise of 60–240 s improved (P=0.001) and over 240 s also improved (P=0.046), but there was no benefit for very short efforts under 60 s (P=0.312). The median improvement was about 2.85%. It was the first to quantify how the benefit differs by duration window.
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Due to the well-defined role of β-alanine as a substrate of carnosine (a major contributor to H+ buffering during high-intensity exercise), β-alanine is fast becoming a popular ergogenic aid to sports performance. There have been several recent qualitative review articles published on the topic, and here we present a preliminary quantitative review of the literature through a meta-analysis. A comprehensive search of the literature was employed to identify all studies suitable for inclusion in the analysis; strict exclusion criteria were also applied. Fifteen published manuscripts were included in the analysis, which reported the results of 57 measures within 23 exercise tests, using 18 supplementation regimes and a total of 360 participants [174, β-alanine supplementation group (BA) and 186, placebo supplementation group (Pla)]. BA improved (P=0.002) the outcome of exercise measures to a greater extent than Pla [median effect size (IQR): BA 0.374 (0.140-0.747), Pla 0.108 (-0.019 to 0.487)]. Some of that effect might be explained by the improvement (P=0.013) in exercise capacity with BA compared to Pla; no improvement was seen for exercise performance (P=0.204). In line with the purported mechanisms for an ergogenic effect of β-alanine supplementation, exercise lasting 60-240 s was improved (P=0.001) in BA compared to Pla, as was exercise of >240 s (P=0.046). In contrast, there was no benefit of β-alanine on exercise lasting <60 s (P=0.312). The median effect of β-alanine supplementation is a 2.85% (-0.37 to 10.49%) improvement in the outcome of an exercise measure, when a median total of 179 g of β-alanine is supplemented. ※ The abstract text as collected and stored via the API by the pipeline. The key summary is written based solely on this text.
View original ↗ PMID 30980076 A Systematic Risk Assessment and Meta-Analysis on the Use of Oral β-Alanine Supplementation Systematic risk assessment and meta-analysis · Adv Nutr, 2019 101 human, 50 animal studies - the only side effect was paresthesia (OR 8.9); no adverse effect on consumers within the doses used.
Key summary
An independent risk-assessment meta-analysisA statistical synthesis combining results of multiple studies into one conclusion. of oral beta-alanine's side effects and safety (101 human and 50 animal studies). The only reported side effect was paresthesia, with an odds ratio of 8.9 versus placeboAn inert dummy treatment used as the comparison baseline., and dropout rates were similar between active and placebo groups. Circulating ALT rose slightly but stayed within clinical reference ranges, and there was no significant change in skeletal muscle taurine or histidine in humans. The authors concluded that within the doses used in research, beta-alanine does not adversely affect those consuming it.
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β-Alanine supplementation is one of the world's most commonly used sports supplements, and its use as a nutritional strategy in other populations is ever-increasing, due to evidence of pleiotropic ergogenic and therapeutic benefits. Despite its widespread use, there is only limited understanding of potential adverse effects. To address this, a systematic risk assessment and meta-analysis was undertaken. Four databases were searched using keywords and Medical Subject Headings. All human and animal studies that investigated an isolated, oral, β-alanine supplementation strategy were included. Data were extracted according to 5 main outcomes, including 1) side effects reported during longitudinal trials, 2) side effects reported during acute trials, 3) effect of supplementation on circulating health-related biomarkers, 4) effect of supplementation on skeletal muscle taurine and histidine concentration, and 5) outcomes from animal trials. Quality of evidence for outcomes was ascertained using the Grading of Recommendations Assessment Development and Evaluation (GRADE) framework, and all quantitative data were meta-analyzed using multilevel models grounded in Bayesian principles. In total, 101 human and 50 animal studies were included. Paraesthesia was the only reported side effect and had an estimated OR of 8.9 [95% credible interval (CrI): 2.2, 32.6] with supplementation relative to placebo. Participants in active treatment groups experienced similar dropout rates to those receiving the placebo treatment. β-Alanine supplementation caused a small increase in circulating alanine aminotransferase concentration (effect size, ES: 0.274, CrI: 0.04, 0.527), although mean data remained well within clinical reference ranges. Meta-analysis of human data showed no main effect of β-alanine supplementation on skeletal muscle taurine (ES: 0.156; 95% CrI: -0.38, 0.72) or histidine (ES: -0.15; 95% CrI: -0.64, 0.33) concentration. A main effect of β-alanine supplementation on taurine concentration was reported for murine models, but only when the daily dose was ≥3% β-alanine in drinking water. The results of this review indicate that β-alanine supplementation within the doses used in the available research designs, does not adversely affect those consuming it. ※ The abstract text as collected and stored via the API by the pipeline. The key summary is written based solely on this text.
View original ↗ PMID 26175657 International society of sports nutrition position stand: Beta-Alanine Position stand (ISSN; industry conflicts of interest) · J Int Soc Sports Nutr, 2015 International Society of Sports Nutrition - 4–6 g/day for 4 weeks raises carnosine; the only side effect is paresthesia (eased by 1.6 g divided doses or sustained-release); benefit is clearest in 1–4 min tasks (industry conflicts of interest should be noted).
Key summary
A beta-alanine position stand from the International Society of Sports Nutrition (ISSN). It concludes that 4–6 g/day for 4 weeks significantly augments muscle carnosine, acting as an intracellular pH buffer, and appears safe in healthy people at recommended doses. The only reported side effect is paresthesia (tingling), which can be reduced with 1.6 g divided doses or a sustained-release form, and 4–6 g/day for at least 2–4 weeks improved exercise performance, most clearly in open end-point tasks and time trials lasting 1–4 min. It states more research is needed on endurance beyond 25 min and on strength. However, this is a society position stand with declared conflicts of interest tied to the sports-nutrition industry, so effect sizes should be read alongside independent meta-analyses.
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The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of beta-alanine supplementation. Based on the current available literature, the conclusions of the ISSN are as follows: 1) Four weeks of beta-alanine supplementation (4-6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer; 2) Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses; 3) 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; 4) 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; 5) Beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance; 6) 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); 7) 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. ※ The abstract text as collected and stored via the API by the pipeline. The key summary is written based solely on this text.
View original ↗ PMID 34333586 Effect of Carnosine or β-Alanine Supplementation on Markers of Glycemic Control and Insulin Resistance in Humans and Animals: A Systematic Review and Meta-analysis Meta-analysis · Adv Nutr, 2021 20 studies (4 human, 16 rodent) - trended toward lower fasting glucose, HbA1cGlycated hemoglobin, a blood marker reflecting average glucose over the past 2-3 months; used to gauge diabetes control., HOMA-IR; certainty moderate (human) and very low (rodent); only 4 human studies.
Key summary
A meta-analysisA statistical synthesis combining results of multiple studies into one conclusion. of carnosine or its precursor beta-alanine on markers of glycemic control and insulin resistanceA state in which cells respond poorly to insulin, so blood glucose does not fall as it should. (4 human and 16 rodent studies, 20 in total). In Bayesian models, supplementation trended toward lower fasting glucose, glycated hemoglobin (HbA1cGlycated hemoglobin, a blood marker reflecting average glucose over the past 2-3 months; used to gauge diabetes control.), and an insulin-resistance marker (HOMA-IR), and lower fasting insulin in humans. GRADEAn international standard for rating the certainty of evidence from high to very low. certainty was moderate for human outcomes and very low for rodent outcomes. The authors said both compounds show potential to improve markers of glycemic control and insulin resistance, while noting that with only 4 human studies more research is needed.
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There is growing evidence that supplementation with carnosine, or its rate-limiting precursor β-alanine, can ameliorate aspects of metabolic dysregulation that occur in diabetes and its related conditions. The purpose of this systematic review and meta-analysis was to evaluate the effect of carnosine or β-alanine supplementation on markers of glycemic control and insulin resistance in humans and animals. We performed a systematic search of 6 electronic databases up to 31 December 2020. Primary outcomes were changes in 1) fasting glucose, 2) glycated hemoglobin (HbA1c), and 3) 2-h glucose following a glucose-tolerance test. A set of additional outcomes included fasting insulin and homeostatic model assessment of β-cell function (HOMA-β) and insulin resistance (HOMA-IR). We assessed risk of bias using the Cochrane risk of bias (RoB) 2.0 (human studies) and the Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) RoB (animal studies) tools; and used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess certainty. We used Bayesian hierarchical random-effects models, with informative priors for human data and noninformative priors for animal data. Inferences were made on posterior samples generated by Hamiltonian Markov Chain Monte Carlo using 90% credible intervals (90% CrI) and calculated probabilities. Twenty studies (n = 4 human, n = 16 rodent) were included, providing data for 2 primary outcomes (fasting glucose and HbA1c) and 3 additional outcomes (fasting insulin, HOMA-β, and HOMA-IR). The model provides evidence that supplementation decreases fasting glucose [humans: mean difference (MD)0.5 = -0.95 mmol · L-1 (90% CrI: -2.1, 0.08); rodent: MD0.5 = -2.26 mmol · L-1 (90% CrI: -4.03, -0.44)], HbA1c [humans: MD0.5 = -0.91% (90% CrI: -1.46, -0.39); rodents: MD0.5 = -1.05% (90% CrI: -1.64, -0.52)], HOMA-IR [humans: standardized mean difference (SMD)0.5 = -0.41 (90% CrI: -0.82, -0.07); rodents: SMD0.5 = -0.63 (90% CrI: -1.98, 0.65)], and fasting insulin [humans: SMD0.5 = -0.41 (90% CrI: -0.77, -0.07)]. GRADE assessment showed our certainty in the effect estimate of each outcome to be moderate (human outcomes) or very low (rodent outcomes). Supplementation with carnosine or β-alanine may reduce fasting glucose, HbA1c, and HOMA-IR in humans and rodents, and fasting insulin in humans; both compounds show potential as therapeutics to improve glycemic control and insulin resistance. This review was registered at PROSPERO as CRD42020191588. ※ The abstract text as collected and stored via the API by the pipeline. The key summary is written based solely on this text.
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