The invention relates to compositions useful in cosmetics and particularly adapted for the treatment of hair, made up of water and 5 to 60 percent of polypeptides having a Formol Nitrogen value in the range between 8 and 17, which polypeptides are the product of subjection of collagen-containing material to heat in the presence of water under conditions of temperature, pressure and time whereby the gel forming character of the protein hydrolysate is reduced, of removal of anions from the hydrolysate by ion exchange and of further hydrolyzing of the hydrolysate with enzyme material having proteolytic activity.