The Muscle Carnosine Response to Beta-Alanine Supplementation: A Systematic Review With Bayesian Individual and Aggregate Data E-Max Model and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and Bayesian meta-analysis of aggregate and individual participant data
PubMed 32922303 · doi:10.3389/fphys.2020.00913
What was done
Authors conducted a systematic review adhering to PRISMA guidelines and a Bayesian meta-analysis using an Emax dose-response model on published aggregate data assessing muscle carnosine (MCarn) response to beta-alanine (BA) supplementation. Meta-regression evaluated potential moderators including dose, sex, age, baseline MCarn, and analytical method. Additionally, an original individual participant data analysis was performed on n = 99 participants from studies conducted within the authors' laboratory.
What was found
The Emax model indicated that human skeletal muscle has a large capacity for non-linear MCarn accumulation and that commonly utilized BA supplementation protocols do not saturate muscle carnosine stores. Neither baseline MCarn nor sex influenced the response to supplementation. Analysis of individual data demonstrated that MCarn is stable without intervention and that 99.3% of participants respond to supplementation (95% CrI: 96.2 to 100).
Why it matters
This analysis establishes that muscle carnosine response to beta-alanine is universal across individuals regardless of sex or baseline levels, and shows that standard dosing regimens leave room for further muscle carnosine accumulation.
Limits
The abstract does not report the total number of included aggregate studies, total pooled sample size, or specific numerical parameters for the Emax model. Individual-level data were limited to participants from a single research laboratory, and functional performance outcomes were not reported in the abstract.
Cited by
- supports Beta-alanine requires 3 to 5 weeks of chronic daily dosing to accumulate sufficiently in muscle tissue before providing performance benefits.