Method of modifying keratin fiber

A method of modifying keratin fibers comprising the steps of:

• a) a catalyst solution impregnation step, comprising sequentially applying a mechanical force to keratin fibers by repeatedly bending or twisting the fibers to the extent of at least 20% followed by relaxation in the presence of an aqueous solution of a transition metal salt at a first pH as a catalyst to weaken and destroy non-keratin under layers jointed to keratin layers in the cuticle cells of said keratin fibers due to differences in mechanical properties of the keratin layers and non-keratin under layers so as to distribute the catalyst solution to the non-keratin under layers;
• b) a catalyst deposition step, which involves adjusting pH of the aqueous solution of step a) to induce the precipitation of the metal salt catalyst wherein said metal salt catalyst is precipitated at the under layers and;
• c) a keratin layer removing step, comprising reacting at least one non-chlorine based oxidizing agent with the keratin fibers in the presence of the precipitated metal salt catalyst, to cause a rapid oxidation reaction at the non-keratin under layers so that the keratin layers may be removed from the non-keratin layers and the under layers may be exposed.