A thermosetting composition having a glass transition temperature of at least 100° C., comprising at least one epoxy resin formed from at least one polyepoxide containing at least two epoxy groups per molecule and at least one aromatic polyamine containing not more than two aromatic rings, at least two primary amino groups per molecule and at least one alkyl substituent containing 1 to 12 carbon atoms located in the position alpha to one of the amine groups, the molar ratio of the amine to the epoxide being such that each amino group corresponds to 1.6 to 2.6 epoxy groups, the thermosetting composition further comprising a flow controller.