What is disclosed are growth hormone secretagogues, and their uses, of the formula
wherein R1 is C6H5CH2OCH2—, C6H5 (CH2)3— or indol-3-ylmethyl; Y is pyrrolidin-1-yl, 4-C1-C6 alkylpiperidin-1-yl or NR2R2; R2 are each independently a C1 to C6 alkyl; R3 is 2-napthyl or phenyl para-substituted by W; W is H, F, CF3, C1-C6 alkoxy or phenyl; and R4 is H or CH3,
or a pharmaceutically acceptable salt or solvate thereof.