This chapter explores the role of dietary supplements in enhancing cognitive and physical performance among esports athletes. It provides an evidence-based review of common supplements such as caffeine, L-theanine, creatine, beetroot juice, polyphenols, probiotics, and lutein, focusing on their physiological mechanisms and relevance to gaming contexts. Specific attention is given to how these compounds influence reaction time, attention, working memory, and mood under cognitive load. While some supplements, such as caffeine and creatine, have robust evidence supporting their effectiveness, others warrant further research. The chapter critically evaluates the applicability of supplementation strategies for esports athletes and outlines future directions for personalized and performance-oriented supplementation.