from wikipedia (http://en.wikipedia.org/wiki/Beta-alanine) where they state
β-Alanine is the rate-limiting precursor of carnosine, which is to say carnosine levels are limited by the amount of available β-alanine. Supplementation with β-alanine has been shown to increase the concentration of carnosine in muscles, decrease fatigue in athletes and increase total muscular work done.
see also (http://fitness.mercola.com/sites/fitness/archive/2011/09/11/why-muscles-are-sore-after-workouts.aspx) where they discuss this.
- Steady Health September 27, 2010
- International Journal of Sport Nutrition and Exercise Metabolism 2005;15:493-514
- Sports Medicine March 1, 2010, 40; 3:247-263
- Video Transcript