Abstract: Cosmetic or personal care compositions, such as for styling hair, comprise a thermoplastic elastomer which is a block copolymer comprising a core polymer having a backbone comprising at least a proportion of C—C bonds and two or more flanking polymers. Each flanking polymer is covalently bound to an end of the core polymer and the copolymer is soluble at a level of at least 1% by weight in water at 25° C. The compositions comprise a cosmetically acceptable diluent or carrier.