Effects of ß-alanine supplementation on exercise performance: a meta-analysis.

ABSTRACT

Due to the well-defined role of ß-alanine as a substrate of carnosine (a major contributor to H+ buffering during high-intensity exercise), ß-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, ß-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 ß-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 ß-alanine on exercise lasting <60 s (P=0.312). The median effect of ß-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 ß-alanine is supplemented.