Blond Absolu Bain Ultra-Violet by Kérastase, an anti-brass shampoo, nourishes your hair while using Ultra-Violet Neutralizers to reduce brassiness. Recognized as one of the best purple shampoos for grey hair and white hair, it's also ideal for processed or bleached-blonde hair. Incorporating this purple shampoo into your routine is a great strategy on how to maintain blonde hair. Its ultra-violet fluid texture neutralizes orange to dark yellow undertones, ensuring your color stays bright and luminous. HOW TO USE: STEP 1 Apply to wet hair. Leave on at least 2 minutes, or longer depending on desired degree of neutralization. STEP 2 Rinse thoroughly.