The subject of the present invention is to provide a novel peptide that can treat, prevent or improve mood disorders. The present invention provides a peptide comprising the amino acid sequence described in SEQ ID No. 1 and having an amino acid length of 6 or more and 20 or less.本發明之課題為提供一種能夠治療、預防或改善情緒障礙之新穎胜肽。本發明提供一種胜肽,包含序列編號1所記載之胺基酸序列,且為6以上、20以下之胺基酸長度。