WHAT IT IS Hair Thickening Fibers - Light Brown are keratin hair fibers that blend and cover thinning and low-density areas of hair for instant thicker fuller-looking hair. WHAT IT DOES Bosley Pro Hair Thickening Fibers - Gray are keratin proteins similar to natural hair. Fibers blend with natural hair that may add density and help create thicker fuller-looking hair. The Fibers cover-up fine and thinning areas of hair and are perfect for cover-up between color treatments.
