Bosley Defence Thickening Treatment for Color Treated Hair What it is: Leave in intensive treatment. What it does: Creates thicker feeling hair while helping to inhibit the action of DHT, protect and repair hair follicles and help support healthy hair function. Extends longevity to color. How to use it: Apply daily to scalp and hair, do not rinse. Features & Benefits: LifeXtend Complex - Hydrates and nourishes while strengthening and fortifying the follicles and hair shaft for thicker, fuller looking hair. Kelp Extract - Helps protect from photo aging, frequent washing and damage due to brushing. Color Keeper Extends longevity of hair color.