Cosmetic agent for temporarily deforming keratin fibers, comprising a polysilicic acid in a cosmetically acceptable carrier, wherein the polysilicic acid is coated with at least one copolymer A formed from at least one monomer A1 according to Formula (A1) wherein R1 is H or CH3, R2 and R3 each independently of each other mean H, OH, C1-10-Alkyl or C1-10-Alkoxy, under the provision that at least one of the radicals R2 or R3 is OH, and n is a whole number from 0 to 20, and at least one monomer A2 according to Formula (A2) wherein R4 is H or CH3, Z is O or NH, and R5 is C1-30-alkyl or C1-30-alkylene-C1-30-alkylether group, use of the agent for temporarily deforming keratin fibers, and method of deforming hair using such agent.