This chapter comprehensively explores biotin, a water-soluble B vitamin, and its impact on human health, particularly hair, skin, and nail health. It explains signs of deficiency, potential benefits of supplementation, and informed usage. Natural dietary sources are discussed, highlighting a holistic approach to well-being. The chapter bridges scientific insights with practical guidance, empowering informed decisions regarding biotin intake and overall health. © 2025 Elsevier B.V., All rights reserved.