The invention relates to the use of aminoalcohol derivatives containing a urea functional group corresponding to the following formula: ##STR1## in which: R.sub.1 represents a linear or branched, saturated or unsaturated alkyl radical having from 8 to 22 carbon atoms; R.sub.2 represents a hydrogen atom or a linear or branched, saturated alkyl radical having from 1 to 6 carbon atoms; R.sub.3 represents a linear or branched, monohydroxylated or polyhydroxylated, saturated alkyl group having from 1 to 10 carbon atoms, in and for the preparation of cosmetic or dermatological compositions. These compounds are used in particular as moisturizing agents in care products for the skin or as conditioning agents in hair products.