Kerasol is a high molecular weight soluble keratin protein with novel physical properties developed primarily for inclusion as a conditioning agent in permanent wave, hair straightening and relaxing formulations. The presence of cystine/cysteine residues in the keratin protein chains offers a mechanism for covalent bonding of the protein to hair via disulphide links formed during a reduction/oxidation treatment. By forming stronger bonds than usually associated with hair conditioning, a permanent effect results.