Most hair masks come with specific instructions, but as a rule of thumb, Townsend says always shampoo your hair before using one to wash away buildup that can affect the mask's efficacy. While there are certainly products that can be used across different hair textures, lengths, curl patterns, thicknesses, colors (natural and unnatural), and needs, hair products are often created with specific consumers in mind. Many are created to address a concern (dandruff, breakage, brittleness, thinning) or to work most effectively for a hair type (4C curls, wavy hair, gray hair).