The present invention is directed to an inlet valve for regulating the pressure at the inlet channel of a vacuum pump (11) comprising: - a first chamber (1) defined by a housing (3) having at least one inlet channel (4) connected to a first supply of a fluid, the first chamber (1) comprising a movable element (5) defining two cavities (1a and 1b) fluidly sealed from each-other and means for exerting a force on the movable element (5); - a second chamber (2) separated from the first chamber (1) by a wall (7) and defined by a housing (3), said second chamber (2) being in direct communication with a process channel (8) of a second supply of a fluid;a valve body (9) slidably mounted in the wall (7) in such a way as to prevent a fluid flow between the second chamber (2) and the second cavity of the first chamber (1b), the valve body (9) having a distal end (9a) in extending into the first cavity (1a) of the first chamber (1) and a proximal end (9b), said valve body being movable between an initial closed state in which the proximal end (9b) is pushed against a sealing flange (10) and a second, opened state, in which a fluid flows from the process channel to the inlet channel (11) of the vacuum pump, characterized in that - the valve body (12) comprises a fluid channel (18) extending through the valve body (12) allowing a fluid flow between the first cavity (6a) and the inlet channel (14) of the vacuum element (1).