research Cuticle damage and the tensile properties of human hair 27 citations , February 1991 Cuticle damage doesn't affect hair's tensile strength; the cortex is responsible for it.
research Effect of ethnicity and treatments on in situ tensile response and morphological changes of human hair characterized by atomic force microscopy 42 citations , August 2008 in “Acta materialia” Different ethnicities and treatments affect human hair strength and structure.