  Mass-loss rates are one of the most relevant parameters determining the
evolution of massive stars. In particular, the rates at which the star loses
mass during the red-supergiant (RSG) phase is the least constrained by the
observations or theory. In this paper, we show how the mass loss during the RSG
phase affects the later evolution of the star, as well as the final type of
supernova towards which it leads. We also discuss some possibilities to
discriminate between blue stars that went through a RSG phase and those which
remained in the blue part of the Hertzsprung-Russell diagram.
