The peptides have the general following formula: X-Pro*-Pro*-Xaa-Y in which: —Xaa is selected from Leucine (Leu, L), Arginine (Arg, R), Lysine (Lys, K), Alanine (Ala, A), Serine (Ser, S), and Aspartic acid (Asp, D); —At the N terminal end of the peptide, X is selected from H, —CO—R1 and —SO2—R1; —At the C terminal end of the peptide, Y is selected from OH, OR1, NH2, NHR1 and NR1R2; —R1 and R2 are, independently from each other, selected from an alkyle, aryle, aralkyle, alkylaryl, alkoxy and aryloxy group, that can be linear, branched, cyclic, poly-cyclic, non-saturated, hydroxylated, carbonylated, phosphorylated and/or sulfured, and which skeletum can comprise an heteroatom, in particular an O, S and/or N atom; —Pro* correspond to a Proline, an analogue or derivative thereof; —if X is H then Y is selected from OR1, NH2, NHR1 and NR1R2, and if Y is OH then X is —CO— or —SO2—R1; and the peptide hypoxanthine-Pro-Pro-Arg being excluded. The invention provides the use of the peptides of above formula I to stimulate the synthesis of the molecules constituting the dermal extracellular matrix, including collagen I and IV and elastin. A cosmetic treatment according to the invention includes anti-aging, anti-wrinkles, improving mechanical properties of the skin, firmness/tone/elasticity/suppleness/flexibility, increasing density and volume of the skin, restructuring effect, fighting stretch marks, improving skin barrier and/or skin hydration.L'invention concerne des peptides de la formule générale suivante : X–Pro*–Pro*–Xaa–Y dans laquelle : • Xaa est choisi parmi la leucine (Leu, L), l'arginine (Arg, R), la lysine (Lys, K), l'alanine (Ala, A), la sérine (Ser, S) et l'acide aspartique (Asp, D) ; • à l'extrémité N-terminale du peptide, X est choisi parmi H, -CO-R1 et -SO2-R1 ; • à l'extrémité C-terminale du peptide, Y est choisi parmi OH, OR1, NH2, NHR1 et NR1R2 ; • R1 et R2 sont choisis, indépendamment l'un de l'autre, parmi un groupe alkyle, aryle, aralkyle, alkylaryle, alco