Polyester oil structurants are obtainable by the reaction of a C4 to C10 Q dicarboxylic acid, a polyol and a C16 to C30, particularly a C20 to C24, monocarboxylic fatty acid. The structurants can be used to provide structure, particularly thickening and/or gelling, in oils of a wide range of polarity. Thickened oils can find application in a range of personal care and other applications.