Creatine supplements are athletic aids used to increase high-intensity athletic performance. Researchers have known of the use of creatine as an energy source by skeletal muscles since the middle of the 20th century. They were popularized as a performance-enhancing supplement beginning in the 1990s.esearchers have known of the use of creatine as an energy source by skeletal muscles since the middle of the 20th century. They were popularized as a performance-enhancing supplement beginning in the 1990s.