The invention provides a peptide and an immunostimulant or hair grower containing the peptide as an active ingredient, as well as a method for hair growth or regrowth promotion by administering an effective amount of the peptide to a mammal. The peptide has 23 or less amino acids and includes the amino acid sequence LHRLKRLRKRL (SEQ ID NO: 1), preferably the amino acid sequence LHRLKRLRKRLK (SEQ ID NO: 9).