The invention relates to a hair treatment agent including 0.1 to 20 weight percent of at least one silicone including groups of the formula (I) as defined herein 0.1 to 20 weight percent of at least one copolymer that includes monomer units of the formulas (V) and (VI) as defined herein and 0.5 to 5 weight percent of 2-phenylbenzimidazole-5-sulfonic acid. The hair treatment agent according to the invention has an improved protective effect against UV radiation and has an improving effect on hair treated therewith with regard to combability, gloss, elasticity, brittleness, and maximum tensile strength.
