Disclosed is the use of the compounds of formula ##STR00001## wherein A is a radical of formula ##STR00002## R.sub.1 and R.sub.5 independently from each other are hydrogen; C.sub.1-C.sub.18alkyl; or C.sub.6-C.sub.12aryl; R.sub.2, R.sub.3 and R.sub.4 independently from each other are hydrogen; or a radical of formula ##STR00003## wherein, in formula (1a), at least one of the radicals R.sub.2, R.sub.3 and R.sub.4 are a radical of formula (1c); R.sub.6, R.sub.7, R.sub.8, R.sub.9 and R.sub.10 independently from each other are hydrogen; hydroxy; halogen; C.sub.1-C.sub.18alkyl; C.sub.1-C.sub.18alkoxy; C.sub.6-C.sub.12aryl; biphenylyl; C.sub.6-C.sub.12aryloxy; C.sub.1-C.sub.18alkylthio; carboxy; --COOM; C.sub.1-C.sub.18-alkylcarboxyl; aminocarbonyl; or mono- or di-C.sub.1-C.sub.18alkylamino; C.sub.1-C.sub.10acylamino; --COOH; M is an alkali metal ion; x is 1 or 2; and y is a number from 2 to 10; for the protection of human and animal hair and skin against the damaging effect of UV radiation.The compounds of formula (1) are high effective UV absorbers for cosmetic formulations aund can be--depending on their physical properties be used in micronized or soluble form.