KérastaseKérastase Cristalliste Lumiere Liquide - Shine Serum

BUY at Birchbox

Ever since we watched the first season of Gossip Girl, we've been huge fans of Blake Lively's flowing waves. So we were excited to learn that the blonde actress was the inspiration behind Krastase's new serum. Specially designed for long hair, the leave-in treatment adds a high-definition shine while sealing each cuticle (bye bye, split ends). Plus, the light, gorgeously scented formula won't weigh down your strands.