Creatine is a compound that comes from three amino acids. Creatine is found mostly in your body's muscles as well as in the brain. Most people get creatine through seafood and red meat — though at levels far below those found in synthetically made creatine supplements. The body's liver, pancreas and kidneys also can make about 1 gram of creatine per day.
Your body stores creatine as phosphocreatine primarily in your muscles, where it's used for energy. As a result, people take creatine orally to improve athletic performance and increase muscle mass.
People also use oral creatine to treat certain brain disorders, neuromuscular conditions, congestive heart failure and other conditions. Topical creatine might be used to treat aging skin.