The invention relates to peptidic compounds of general formula (I) R1-(AA)n-X1-X2-Ile-Gln-Ala-Cys-Arg-Gly-X3-(AA)p-R2 as caspase-14 activators. The invention also relates to a cosmetic or pharmaceutical composition comprising at least one peptide of general formula (I), in a physiologically acceptable medium, and to the use of said composition for preventing and/or repairing damage to deoxyribonucleic acid, for preventing and/or treating cutaneous signs of ageing and photo-ageing, and for improving the skin barrier function. The invention further relates to a cosmetic treatment method for preventing and/or treating cutaneous signs of ageing and photo-ageing, and for preventing and/or repairing damage caused by ultraviolet radiation.