The hair and other keratinaceous fibers such as wools, quills and spines are widely studied at macroscopic level, from the response to chemical treatments [3], [4] and [5] to inherent mechanical properties [6], [7], [8] and [9]. However at molecular level there is much lesser information about these fibers and their ultrastructure. This is probably due to the limitations in the characterization of the entire IFS structure, since it has some highly disordered regions difficult to crystallize, challenging the use of traditional techniques such as X-ray crystallography and NMR. In a few works, computational methods have been applied with success in the study of these fibers structure at molecular level, overcoming these limitations. Computational molecular models of keratin structures (mainly dimers and some tetrameters of α-keratin) have been developed, gathering the available data from several sources such as the known amino acid sequence of keratin proteins, the crystallographic structure of some keratin fragments already unveiled and available information about other fibrous proteins like vimentin and lamin which share similar ultrastructure of the IFS with keratin