Treatment of hair fibers involves: (a) applying a reducing composition (A) containing reducing agent(s) (I) selected from non-sulfur reductants and protected thiols； and (b) heating the fibers to 60[deg]C or more using a heating iron, before or after optional rinsing of the fibers. Alternatively (I) are selected from sulfites and bisulfites, in which case (A) is free of ceramides. An independent claim is included for a cosmetic kit having a first compartment containing (A) and a second compartment containing an oxidizing composition (B).
