Disclosed are the novel compounds as growth hormone secretagogues represented by structural Formula (I), wherein R1 is, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, or substituted or unsubstituted amino, X is —CO— or —SO2—, Y is Formula (II), wherein n is an integer from 0–4, R4 is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, R5 and R6 are independently selected from hydrogen, substituted or unsubstituted alkyl, or R5 and R6 or R4 and R5 are taken together to form substituted or unsubstituted alkylene, R2 is hydrogen, or substituted or unsubstituted alkyl, R3 is substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, D is substituted or unsubstituted amino, substituted or unsubstituted alkoxy, or substituted or unsubstituted alkylthio, * represents an asymmetric center, and pharmaceutically acceptable salts and individual isomers thereof, which have growth hormone releasing activity in humans or animals.