Cyclic peptide and a medicament, external preparation and cosmetic comprising said cyclic peptide

A method of using an external preparation comprising applying the external preparation to skin and/or mucosa of a subject, wherein the external preparation comprises a cyclic peptide having an amino acid sequence expressed by the Formula I:

• wherein,
• X1 denotes Gly, Val, Ala, Ser or Thr,
• X2 denotes Arg, Gln or His,
• X3 denotes Lys or Arg,
• X4 denotes Met, Leu or Ile,
• X5 denotes Ile or Val,
• X6 denotes Ser or Gly,
• X7 denotes Ser or Ala,
• X8 denotes Ser, Gln, Val, Ala, Thr, Leu, Ile or Met,
• X9 denotes Ser, Val, Ala or Thr,
• X10 denotes Gly or Arg,
• X11 denotes Leu, Met, Ile, Val or Ala,
• X12 denotes Gly, Ser or Ala, and
• the line connecting two Cys denotes a disulfide bond,
• and wherein said amino acid sequence does not have a peptide bond that is not between the amino acids constituting said amino acid sequence,
• or a derivative thereof or a pharmaceutically acceptable salt thereof.