Hair is treated with a copolymer of an unsaturated ester and a styrene sulphonate monomer to reducing damage to hair caused by subsequent heat treatment. The styrene sulphonate monomer is desirably sodium styrene sulphonate and the unsaturated ester is desirably of an unsaturated monocarboxylic acid, such as (meth)acrylic acid, or dicarboxylic acid, such as maleic acid, and an alcohol, desirably an alkoxylated alcohol such as ethoxylated lanolin alcohol. Formulations for hair treatment generally include from about 0.5 to about 25% by weight of the copolymer.
