Use of at least one peptide of formula: X - (Xaa 1) n - Pro ∗ - (Xaa 2) m - Y with: - n = 0 or 1; - m = 0 or 1 and if m = 0 then n ≠ 0; - Xaa 1 is selected from Leucine (Leu, L), Proline (Pro, P), Serine (Ser, S) and Glutamine (Gln, Q); - Xaa 2 is selected from Alanine (Ala, A), Methionine (Met, M), Arginine (Arg, R), Glycine (Gly, G) and Serine (Ser, S); - At the N terminal end of the peptide, X is selected from H, -CO-R 1 and -SO 2 -R 1; - At the C terminal end of the peptide, Y is selected from OH, OR 1, NH 2, NHR 1 or NR 1 R 2; - R 1 and R 2 being independently from each other, an alkyl chains of 1 to 24 carbon atoms; - Pro ∗ corresponding to a Proline, an analogue or derivative thereof selected from: - azetidine-2-carboxylic acid, β-proline, pipecolic acid, nipecotic acid, thio-proline, 4-hydroxy-proline and 3,4-dehydro-proline, - compounds resulting from the substitution of the proline by an R group selected from piperidin-4-yl (position 1 on the nitrogen), phenyl or dimethyl (position 3), phenyl, OH, NH 2, F, F 2, CF 3, benzyl, cyclohexyl, oxo, bromobenzyl, SH or phenoxy (position 4), phenyl, dimethyl or oxo (position 5) and phenyl or cyclohexyl (position 4+5), and - 3-carboxy-morpholine, 2-carboxy-morpholine, 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid and its hydroxylated derivative and 1,2,3,4-tetrahydroisoquinoline-1-carboxylic acid; excluding the peptides where X=H and Y=OH or NH 2 for a non therapeutical cosmetic pro-pigmenting treatment of skin and its appendages. - n = 0 or 1; - m = 0 or 1 and if m = 0 then n ≠ 0; - Xaa 1 is selected from Leucine (Leu, L), Proline (Pro, P), Serine (Ser, S) and Glutamine (Gln, Q); - Xaa 2 is selected from Alanine (Ala, A), Methionine (Met, M), Arginine (Arg, R), Glycine (Gly, G) and Serine (Ser, S); - At the N terminal end of the peptide, X is selected from H, -CO-R 1 and -SO 2 -R 1; - At the C terminal end of the peptide, Y is selected from OH, OR 1, NH 2, NHR 1 or NR 1 R 2; - R 1 and R 2 being independently from each other, an alkyl chains of 1 to 24 carbon atoms; - Pro ∗ corresponding to a Proline, an analogue or derivative thereof selected from: - azetidine-2-carboxylic acid, β-proline, pipecolic acid, nipecotic acid, thio-proline, 4-hydroxy-proline and 3,4-dehydro-proline, - compounds resulting from the substitution of the proline by an R group selected from piperidin-4-yl (position 1 on the nitrogen), phenyl or dimethyl (position 3), phenyl, OH, NH 2, F, F 2, CF 3, benzyl, cyclohexyl, oxo, bromobenzyl, SH or phenoxy (position 4), phenyl, dimethyl or oxo (position 5) and phenyl or cyclohexyl (position 4+5), and - 3-carboxy-morpholine, 2-carboxy-morpholine, 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid and its hydroxylated derivative and 1,2,3,4-tetrahydroisoquinoline-1-carboxylic acid; - azetidine-2-carboxylic acid, β-proline, pipecolic acid, nipecotic acid, thio-proline, 4-hydroxy-proline and 3,4-dehydro-proline, - compounds resulting from the substitution of the proline by an R group selected from piperidin-4-yl (position 1 on the nitrogen), phenyl or dimethyl (position 3), phenyl, OH, NH 2, F, F 2, CF 3, benzyl, cyclohexyl, oxo, bromobenzyl, SH or phenoxy (position 4), phenyl, dimethyl or oxo (position 5) and phenyl or cyclohexyl (position 4+5), and - 3-carboxy-morpholine, 2-carboxy-morpholine, 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid and its hydroxylated derivative and 1,2,3,4-tetrahydroisoquinoline-1-carboxylic acid; excluding the peptides where X=H and Y=OH or NH 2 for a non therapeutical cosmetic pro-pigmenting treatment of skin and its appendages.