PROBLEM TO BE SOLVED: To provide a kisspeptin agent with a stronger action as an excellent hormone preparation or as the preventive, therapeutic, and metastasis inhibiting agent of hormone sensitive cancer.SOLUTION: A kisspeptin agent consisting of Tyr-Asn-Trp-Asn-Ser(COR)-Phe-Gly-Leu-Arg-Tyr-NHand Ser(COR)-Phe-Gly-Leu-Arg-Tyr-NH(R is a substituted or unsubstituted straight chain or branched chain alkyl group of carbon number 1-20) is produced by synthesizing a peptide using 4-(2,4-dimethoxyphenyl-Fmoc-aminomethyl)-phenoxyl resin which is one of AM resins as a solid-phase carrier removing a triphenylmethyl group which is a protective group of a hydroxyl group of a Ser side chain, among the protective groups of each amino acid side chain in the peptide using 1% trifluoroacetic acid and selectively acylating it by reacting octanoic acid and WSCI with the hydroxyl group of the Ser side chain after removing of the protective group.
