Methods and compositions for preventing or reducing hair frizz. The compositions are anhydrous and comprise at least one polysiloxane fluid component selected from an amodimethicon e and a polysiloxane component comprising a plurality of hindered amine side chains. The compositions also comprise a silicone-compatible, volatile liquid carrier component, preferably selected from a low molecular weight, volatile siloxy component; a hydrocarbon; and an alcohol. The compositions are preferably serums or fluids, and are suitable for use in a conditioner, as a “leave-in” hair care product, or as a touch-up hair care product suitable for use during the day.