Box dyes come with super-conditioning treatments but they’re usually gonzo after only a shower or two. Continue returning the vitamins and proteins you withdrew for at least a few weeks—we would suggest enlisting a blend of reparative oils to do it. Oil permeates sapped strands with ease, and we like Sally Hershberger‘s Hyper Hydration Super Argan Serum ($16 at Shoppers Drug Mart) the best. Its trifecta of oils (Argan, Bran, and Amala) is jacked with antioxidants and proteins to drench parched pores and smooth split ends fast.