An experimental study on the evolution of localized disturbances in pipe Poiseuille flow has been performed. The aim was to investigate the relevance of the theoretical findings on the algebraic transient growth mechanism. For non-axisymmetric disturbances the amplitudes and the propagation velocities were measured in the laminar regime. The initial disturbances were induced radially through the pipe wall and had a distribution in the azimuthal direction corresponding to a periodicity of one and five, respectively. The amplitude of the resulting streamwise velocity perturbation was measured at different radial and axial positions by means of laser doppler velocimetry. In the laminar regime, the results showed that the disturbance peaks are actually amplified but will eventually decay as predicted in the theory. The peak of an initial disturbance of periodicity five showed a rapid amplification to a maximum before the decay sets in. The initial disturbance of periodicity gave a more slowly varying disturbance peak level over the investigated interval. The propagation speed of the front of the disturbances was in the range of 0.86-0.9 times the centreline velocity. The propagation speed of the disturbance peaks was in the range of 0.51 to 0.80 times the centreline velocity and dependent on the azimuthal distribution of the initial disturbance.