Beta-Alanine for Athletic Performance.  What is beta alenine Beta-alanine is a naturally occurring amino acid that is used by the body to produce carnosine, a dipeptide that is concentrated in the skeletal muscles and the brain. Beta-alanine is not used to build proteins, unlike other amino acids. Supplementing with beta-alanine can increase the concentration of carnosine in muscles, which has been shown to improve athletic performance, especially during high-intensity exercises that cause fatigue and muscle acidosis. Beta-alanine supplements are often used by athletes, bodybuilders, and fitness enthusiasts to enhance endurance, increase strength, and delay fatigue. However, it is important to note that beta-alanine may cause a harmless tingling sensation in the skin, known as paresthesia, which can be uncomfortable for some people.