A deformable insole (1) for footwear defining an upper surface (2) adapted in use to face towards the sole of a user's foot, and a lower surface (3) adapted in use to face towards the sole of the footwear.The insole comprises a housing (4) interposed between a sector of the upper surface and a sector of the lower surface, the housing (4) being suitable for containing an elastic element (5) and holding it firmly between the sectors.
