Creatinine occurs naturally in muscle tissue. It helps produce the energy needed for heavy lifting, high-intensity exercise, and other high energy pursuits.

• In healthy individuals, the daily level of creatinine in the blood remains stable.
• The kidneys metabolize and excrete creatinine.
• Some people take creatinine supplements to build and maintain muscle mass. Too much creatinine in the blood, however, can cause liver, kidney, and heart problems.