Despite being widely studied for decades, creatine supplementation still seems to hold many "secrets" and possible as-yet-unknown benefits can be revealed. Historically recognized as a supplement primarily for athletes, research conducted over time has revealed that, in addition to enhancing sports performance, it can improve the general population's quality of life and health. This narrative review aims to show some aspects of creatine supplementation, presenting the main findings that contribute to the current understanding of creatine supplementation for athletes and for both healthy and diseased children and older adults.