Creatine ethyl ester, also known as creatine ester, cre-ester and CEE, is a substance sold as an aid for athletic performance and for muscle development in . It is an derivative of , from which it is made. In the body, CEE is converted back into creatine. The ethyl ester is said to have a much better absorption rate and a longer in the body than regular , because it is slightly more . However, these claims have not yet been conclusively proven by independent research, and in fact a study presented at the 4th International Society of Sports Nutrition (ISSN) annual meeting demonstrated that that the addition of the ethyl group to creatine actually reduces acid stability and accelerates its breakdown to .
As a supplement, the compound was developed, patented and licensed through , the technology transfer entity of the , and is sold under numerous brand names.