Beta-alanine supplementation in female masters athletes does not produce significant improvements in isokinetic performance until after 28 days of daily intake, as no significant differences are observed at 7, 14, or 21 days, indicating that performance effects are dependent on cumulative intramuscular carnosine accumulation.

Beta-alanine enters muscle cells and combines with another molecule to form carnosine. Over weeks, carnosine builds up in the muscle. When the muscle works hard, it produces acid. Carnosine soaks up that acid, keeping the muscle environment less acidic. This lets the muscle fibers contract more forcefully for longer, especially during repeated intense efforts. It takes about four weeks for enough carnosine to build up to make this difference.