text: No, it doesn't.  But it does make it appear this way. Before you shave the hair is different lengths and some of it lighter.  When you shave and it grows back it is all the same length and darker because it hasn't had a chance to get bleaced by the sun, therefore it looks like it is thicker and darker.  Shaving can not change the way hair grows out from the pores, it cuts it off at the surface.