Nioxin Night Density Rescue Serum is an overnight leave-in treatment designed to combat hair thinning and support fuller-looking hair while you sleep. This lightweight, non-greasy serum works during the scalp’s natural nighttime regeneration process to help reduce oxidative damage that contributes to hair fall. With consistent use, it helps improve hair density by creating a more balanced scalp environment, leaving hair stronger and visibly thicker over time. Ideal for all hair types, this serum fits seamlessly into your evening routine without leaving residue on pillows or sheets.