A cell-penetrating peptide characterized in that it comprises an amino acid sequence: X1X2X3WWX4X5WAX6X3X7X8X9X10X11X12WX13R (SEQ ID No: 10), wherein X1, is beta-A or S, X2 is L or none, X3 is R or none, X4 is L, R or G, X5 is R, W or S, X6 is S, P or T, X7 is W or P, X8 is F, A or R, X9 is S, L, P or R, X10 is R or S, X11 n is W or none, X12 is A, R or none and X13 is W or F, and wherein if X3 is none, then X3, X11 and X12 are none as well.