Bosley Hair Thickening Fibers are a safe and effective way to eliminate the appearance of baldness and thinning hair. It is perfect for both men and women with hair loss as well as recent hair transplant patients. They are available in a variety of hair colors: black, dark brown, medium brown, light brown, auburn and blond. Keratin Hair Fibers blend and cover thinning and low density areas of hair for instant thicker fuller-looking hair. Creates instant thicker fuller-looking hair. Electrostatically attaches to existing hair follicles. Covers-up fine and thinning areas of hair. Perfect for temporary cover-up post procedure. Enhances existing procedure density.