This classic multipurpose product — which could best be described as a mash-up between a stying cream and a hair oil — is a favourite amongst hairstylists for its ability to not only create definition and separation in the hair, but also add moisture and shine. When it comes to bobs specifically, hairstylist Teddi Cranford (founder of White Rose Collective salon in New York City), likes to use Bumble & Bumble Brilliantine (£22) "to add healthy-looking texture" to hair textures that range from straight to wavy, scrunching it in from mid-lengths to ends.