Tripeptides, compositions comprising the same, and uses in particular cosmetics

Tripeptide X-KGH-Z or X-KHG-Z; at the N-terminus X is selected from H, -CO-R1 and -SO2-R1; at the C-terminal end Z is selected from OH, OR1, NH2, NHR1 or NR1R2; and R1 and R2 being, independently of one another, selected from an alkyl, aryl, aralkyl, alkylaryl, alkoxy and aryloxy group, which may be linear, branched, cyclic, polycyclic, unsaturated, hydroxylated, carbonylated, phosphorylated and / or or sulfur, said group having 1 to 24 carbon atoms and may have in its backbone heteroatom O, S and / or N; with the exception of tripeptides in which (X = H and Z = OH) or (X = H and Z = NH2). These tripeptides stimulate the synthesis of the molecules constituting the dermal extracellular matrix, in particular collagen 1 and 4 and elastin, and can be used for a cosmetic treatment including anti-aging, anti-wrinkles and fine lines, to improve the mechanical properties of the skin. firmness / tone / elasticity / suppleness, to increase the density and the volume of the skin, for a restructuring effect and / or to fight against stretch marks.