An accessory for a syringe is disclosed, including a body with a proximal end having at least one zone for application of an injection force in order to apply a force for discharging a product from the syringe, and a distal end having a bearing element for bearing against a needle mounted on the mouth of the syringe with a force that includes a radial component perpendicular to the longitudinal axis of the syringe and directed towards the centre of the syringe. An assembly including such an accessory and a syringe is also disclosed.
