The present invention is aimed for providing a novel peptide with a high drug efficacy and strong effect, a medicament or external preparation comprising it, specifically a prophylactic or therapeutic for dermatitis, rhinitis or alopecia, or a hair growth stimulant, a hair growing agent, an antipruritic or a skin-care product. The present invention achieved said aim by providing a cyclic peptide having an amino acid sequence expressed by the Formula I or a derivative thereof or a pharmaceutically acceptable salt thereof, wherein the amino acid sequence does not have a peptide bond that is not between the amino acids constituting the amino acid sequence.
