Apply to clean, damp hair mid-length to ends and work through with fingers. Start with two pumps for shoulder-length hair. Use more for longer, thicker hair, less for fine or short hair. Leave on for 10 minutes. Rinse fully and style as usual. Product Tip: For the deepest repair possible at home, use with No. 0 Intensive Bond Building Hair Treatment and No. 3 Hair Perfector (both sold separately) once a week or as needed.