A method of protecting the internal protein of hair from damage by ultraviolet light, comprising the step of applying, to the hair, a hair treatment composition comprising a lactone, a disaccharide, an inorganic salt and an organic acid or salt thereof, having a pH in the range of from 3 to 6.5 prior to the application of an ultraviolet light to the hair, and a use of such a hair treatment composition, in the treatment of hair, to protect hair from damage by ultraviolet light.
