It is provided a WPC extrusion profile comprising a WPC material, in which plant fibers are embedded in a plastic matrix, wherein the WPC material has a content of naturally growing plant fibers of between 30 and 75 wt-%, and the WPC extrusion profile includes at least one foam-filled hollow chamber. The at least one hollow chamber of the WPC extrusion profile is completely filled up with a foam, in particular a closed-pore foam. The foam includes or consists of a plastic material of the same type of plastic as the matrix of the WPC material. The foaming is effected by using a physically acting blowing agent, in particular CO2, wherein the density of the foam is less than 0.4 g/cm3 and the average cell size of the foam has a mean diameter of less than 0.4 mm.