No ergogeniceffect of β-alanine on repeated sprint ability: a systematic review and multilevel meta-analysis of randomized controlled trials

Objective 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 (RSA)—governed by extremely brief work bouts and phosphocreatine (PCr) kinetics—remains equivocal. Methods A systematic search of PubMed, Web of Science, Scopus, Cochrane Library, Embase and SPORTDiscus was conducted up to January 2026 (PROSPERO: CRD420261304011). Eligible studies included randomized controlled trials (RCTs) investigating oral beta-alanine supplementation (≥ 2 weeks) versus placebo on RSA in healthy populations. Outcomes were standardized into Standardized Mean Differences (SMD, Hedges’ g). To account for the statistical dependency of multiple effect sizes extracted from individual cohorts, a multilevel random-effects model was employed. Methodological quality was assessed using the Cochrane RoB 2.0 tool, and the certainty of evidence was evaluated via the GRADE framework. Results Among 17 included RCTs, the meta-analysis revealed no statistically significant improvements in Mean RSA Performance (SMD = −0.018, 95% CI [−0.207, 0.170], p = 0.841), Peak RSA Performance (SMD = 0.205, 95% CI [−0.073, 0.483], p = 0.130), or Fatigue Decrement (SMD = −0.020, 95% CI [−0.516, 0.476], p = 0.929). Furthermore, subgroup and meta-regression analyses confirmed these null findings were not significantly moderated by total administered dose, duration, exercise modality, or training status. Conclusion In conclusion, chronic β-alanine supplementation does not provide a clear improvement in total work capacity, maximal anaerobic power, or fatigue resistance during repeated sprinting. The augmented intracellular buffering from carnosine may be insufficiently aligned with the acute metabolic demands of RSA, which is primarily dictated by PCr depletion and oxidative recovery rather than maximal glycolytic acidosis. Systematic review registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420261304011 , identifier CRD420261304011.