It seems like you can't open a cycling magazine, read a running forum, or speak to an exercise enthusiast without being drawn into a discussion about sports nutrition supplements. For decades, marketers have been targeting audiences with sponsorship and images highlighting the association between sports nutrition supplement consumption and successful sportsmen, sportswomen and sporting events. One supplement that has attracted recent attention is β-alanine. With article headlines such as "β-alanine - the new kid on the ergogenic block" and "β-alanine - the natural messiah for intense exercise" becoming ever so common, it would seem that β-alanine is the new magic bullet. There is a slowly growing body of literature to support the use of β-alanine in specific groups of athletes. However, additional research is required to fine-tune protocols for individualised and event-specific use. This thesis focuses on new scientific evidence behind issues relating to β-alanine supplementation and high-intensity endurance exercise performance.