Oligopeptides according to formula (I) and/or (II), R1-Tyr-Pro-Trp-Phe-NH2 (I, SEQ ID NO:1); R1-Tyr-Pro-PhePhe-NH2 (II, SEQ ID NO:2), wherein R1 is linked to the NH2-group of the amino-terminal part of Tyr and is selected from the group consisting of —H; a linear saturated or unsaturated or branched saturated or unsaturated acyl group having 1 to 24 carbon atoms, which may be functionalized by a —OH, —SH, —COOH or —CONH+ group; a sterol or a sphingolipid group which is linked to the amino terminal part of Tyr via a bifunctional linker are disclosed. Cosmetic compositions containing the oligopeptides are also disclosed.