BACKGROUND: Several technical aspects of scalp-reduction procedures still need to be clearly elucidated: in particular, (a) the quantitative effects provided by different amounts of subgaleal undermining, (b) the immediate gains provided by increasing amount of tension when advancing a scalp flap, and (c) the eventual benefits provided by galeotomies. OBJECTIVE: The aim of the present paper is to report on some biomechanical properties of scalp flaps as related to serial scalp reduction procedures for correction of male pattern baldness. METHODS: Data were collected by stepwise loading of 20 scalp flaps, obtained by a reversed-Y scalp incision, after increasing amounts of undermining, as well as after performing three galeotomies. RESULTS: Increasing amounts of tension (while advancing a scalp flap) affect the compliance of a scalp flap in a non-linear fashion; increasing amounts of undermining permit obtaining significant, but not proportional, gains; performing galeotomies is a useful adjunct to decrease the amount of closing tension when performing scalp-reduction procedures. CONCLUSION: When performing serial scalp reductions, to take into account the biomechanics of scalp flaps may be of some utility in obtaining an optimal result.