A dispenser includes a hollow body (2) able to be inserted into a bottle, a piston (7) able to slide in the body (2) between raised and lowered position, a hollow stem (8) able to slide in the body (2) to command the actuation of the piston (7), opening and closing element (10) active between the stem (8) and the piston (7) to put in fluid communication the cavity of the stem (8) with the interior of the body, a retaining ring integral with the body (2) and inserted within it, elastic element active between the ring and the stem to contrast the free sliding of the stem and of the piston within the body. The dispenser further includes an end stop structure integral with the body and positioned in a bottom portion thereof to define an end stop arrest for the sliding of the stem within the body.