Abstract: The cosmetic agent contains from 0.01 to 10 percent by weight of at least one silane of formula RmSiX4-m, wherein m=0 to 4, R is a nonhydrolyzable organic group and X is a hydrolysable group, or a salt thereof. The method for improving the condition of hair, particularly in terms of protection, hardening, strengthening, sealing, restructuring, repairing, stabilizing, enhancing the luster, facilitating the combability and shortening the hair-drying time, includes bringing the aforesaid cosmetic agent into contact with the hair for a period of 10 seconds to 60 minutes at a temperature between 20° C. and 60° C.