Compounds useful for the treatment and/or care of the skin, hair, nails and/or mucous membranes

A compound of formula (I):

• R1-Wm-Xn-AA1-AA2-AA3-AA4-AA5-AA6-AA7-AA8-AA9-Yp-
• Zq-R2 (I),
• its stereoisomers and/or its cosmetically or pharmaceutically acceptable salts, wherein:
• AA1 is Phe;
• AA2 is Trp;
• AA3 is selected from the group consisting of Met, Leu and Ile;
• AA4 is selected from the group consisting of Lys, Arg and Gln;
• AA5 is Arg;
• AA6 is Lys;
• AA7 is selected from the group consisting of Arg, Lys and His;
• AA8 is selected from the group consisting of Val, Ile, Leu and Met;
• and
• AA9 is Pro;
• W, X, Y and Z are each independently an amino acid;
• m, n, p and q are each independently 0 or 1;
• m+n+p+q is less than or equal to 2;
• R1 is selected from the group consisting of H, a polymer derived from polyethylene glycol, a non-cyclic aliphatic group, alicyclyl, heterocyclyl, heteroarylalkyl, aryl, aralkyl and R5—CO—, wherein R5 is selected from the group consisting of H, a non-cyclic aliphatic group, alicyclyl, aryl, aralkyl, heterocyclyl and heteroarylalkyl;
• R2 is selected from the group consisting of —NR3R4, —OR3, —SR3, wherein R3 and R4 are independently selected from a group consisting of H, a polymer derived from polyethylene glycol, a non-cyclic aliphatic group, alicyclyl, heterocyclyl, heteroarylalkyl, aryl and aralkyl;
• and
• R1 and R2 are not amino acids.