I used to avoid using serums to hydrate my curls because I hated the oily feeling they left behind. But I recently discovered one that I'm loving because it's so light and it moisturizes without any greasy residue. Amika's Obliphica Oil Serum Treatment promises "deep hydration" and is "rich in regenerative and toning properties." I apply a tiny amount on wet hair to reduce frizz during blow-drying, but it can be used to smooth dry hair, too. The product (infused with Obliphica and Moroccan Argan oils) leaves hair feeling smooth and silky and has a subtle, fruity scent that's perfect for spring and summer. (I also love the nourishing mask from this line – it's rich and instantly helps to refresh dry hair.) The serum sells for $30 at www.folica.com.