LHRH antagonists comprising aminoacyl residues modified position 5 and 6.

A class of potent LHRH decapeptide antagonists RESIDUES HAVE aminoacyl N-alkylated where Part SIDECHAIN ​​RESIDUE IS A 4- (amino-substituted) phenylalanyl, 4- (substituted amino) cyclohexylalanyl, or {OG} - (substituted amino) alkyl group, and further aminoacyl residues positioned 5 ARE IN N-alkylated nitrogen atom COLUMN peptide.