A conditioning hair lightener system, compositions, method, and kit therefor, is disclosed which ameliorates the deleterious effects of chemical oxidative hair lightening on the strength and subjective properties of hair. The conditioning hair lightener system comprises a conditioning hair lightener emulsion having a pH of at least about 8 prepared from at least two separate components, (A) and (B). Component (A) preferably is a substantially anhydrous, substantially free-flowing composition comprising an effective hair conditioning amount of a water-dispersible, self-emulsifying, fatty acid-derived conditioner, an effective hair lightening amount of a peroxy salt compound, optionally an effective hair protective amount of hair protectant, deswelling agent, and optionally, a water-soluble cosmetic adjuvant. Component (B) preferably is an aqueous medium containing hydrogen peroxide or hydrogen peroxide source. Components (A) and (B) are maintained separate until substantially immediately before use, and are mixed together to provide a conditioning hair lightener emulsion.