Experimentation with human growth hormones by America's teens more than doubled in the past year, as more young people looked to drugs to boost their athletic performance and improve their looks, according to a new, large-scale national survey. ADVANCE FOR RELEASE JULY 23, 2014, AT 12:01 A.M. EDT. THIS STORY MAY NOT BE PUBLISHED, BROADCAST OR POSTED ONLINE BEFORE 12:01 A.M.