We provide a systematic renormalization group formalism for the mass effects in the relation of the pole mass m Q pole and short-distance masses such as the MS¯¯¯¯¯¯¯ mass m¯¯¯¯¯Q of a heavy quark Q, coming from virtual loop insertions of massive quarks lighter than Q. The formalism reflects the constraints from heavy quark symmetry and entails a combined matching and evolution procedure that allows to disentangle and successively integrate out the corrections coming from the lighter massive quarks and the momentum regions between them and to precisely control the large order asymptotic behavior. With the formalism we systematically sum logarithms of ratios of the lighter quark masses and m Q , relate the QCD corrections for different exter...