The present invention is a novel peptide with a rapid onset of drug effect and efficacy and a long remission maintenance period, a pharmaceutical or external preparation containing the peptide, particularly a dermatitis, rough skin, rhinitis, alopecia, a prophylactic or therapeutic agent for hair loss, and a hair growth agent, The purpose is to provide hair restorers, antipruritics, skin care products and the like. The present invention includes a cyclic peptide or a derivative thereof having a amino acid sequence represented by formula I, wherein the amino acid sequence does not have a peptide bond other than amino acids constituting the amino acid sequence, or a pharmaceutically acceptable product thereof. The above objective has been achieved by providing possible salts.本発明は、薬効、効能の効果発現が早く寛解維持期間が長い新規ペプチド、これを含む医薬や外用剤、特に皮膚炎、肌荒れ、鼻炎、脱毛症、薄毛に対する予防または治療剤や発毛剤、育毛剤、鎮痒剤、スキンケア用品などを提供することを目的とする。本発明は、式Ｉで表されるアミノ酸配列を有し、当該アミノ酸配列が、当該アミノ酸配列を構成するアミノ酸同士以外のペプチド結合を有さない、環状ペプチドもしくはその誘導体またはこれらの薬学的に許容可能な塩を提供することにより、上記目的が達された。
