Creatine Products | Cleanchem - Creatine is a naturally occurring compound found in muscle cells and is widely used as a supplement to enhance athletic performance. It helps to regenerate ATP (adenosine triphosphate), which is the primary energy carrier in cells, especially during high-intensity physical activity. Creatine is commonly used by athletes to improve strength, power, and endurance in sports like weightlifting and sprinting. Side effects may include weight gain due to water retention and potential kidney stress with long-term, excessive use.