"Obsessica Simpson! This makes my hair incredibly shiny and, unlike most Kérastase, this particular line doesn't weigh the hair down at all. Kérastase is usually focused on repair, and typically there's a heaviness to its conditioners, but not this one! It's all shine and volume, which is a very difficult combo to find."

Kérastase Lait Crystal, $40, available at Kérastase.