Everyone we've ever spoken to who has tried the Elvive Great Lengths Serum has absolutely loved it. Now, the serum just got a sister, the L'Oréal Paris Dream Lengths Anti-Frizz Serum (£8), which promises all of the same benefits of the original Great Lengths Serum — repairing split ends and preventing damage — with the addition of heat protection, and frizz-taming properties.