Kérastase Nutritive 8H Magic Night Serum While you're asleep, this bestselling Kérastase Nutritive 8H Magic Night Serum ($55) will be hard at work hydrating hair so it's soft, moisturised, and easy to style when you wake up again. There's iris root extract inside this leave-in product to coat hair and keep natural nutrients locked in, along with a blend of vitamins to seal roots with a satiny finish. Image Source: sephora.com Kérastase Nutritive 8H Magic Night Serum $55 from sephora.com Buy Now