A high-pressure regulator includes body having a pressure inlet and a pressure outlet. A piston is disposed in the body and fluidly coupled to the pressure inlet and the pressure outlet. The piston is configured to operate in compression to contact a seat ring for the purpose of controlling the flow of fluid from the pressure inlet to the pressure outlet in response to a pressure applied to a surface of the piston via the pressure outlet. A piston seat circumferentially engages the piston to provide an improved seal at low temperatures.