Gloss: Adds shine and adjusts the tone (say, if your highlights are too bright or brassy, a gloss will subdue them) A gloss penetrates the hair’s cuticle, so it lasts two to four weeks. A glaze, on the other hand, simply coats the shaft with shine and semipermanent color; it’s like putting a top coat of polish on your hair, and it lasts a week or two..A hair gloss is a transparent, semi-permanent shine service that can be done at the salon or at home. It works to fill the hair shaft, closing the cuticle, creating a smooth surface that light bounces off for dazzling shine. It coats the hair strand, creating a protective shield that keeps color molecules in and not down the drain.A gloss is very acidic and closes the hair and the cuticle tightly. The result is a very smooth surface texture that will reflect a lot lighter and have a much softer feel to it.