Infusium 23 PRO Original Leave-In Treatment infuses hair with a Pro-Vitamin B5 formula to deeply penetrate and repair the cuticle layers from damage. Detangles and strengthens, while helping to protect against breakage. Original Leave-In Treatment formula is lightweight, so it won't weigh hair down. Can be used immediately following chemical processing to help seal the cuticle, leaving hair healthy-looking with superb manageability and shine.