Hair thickening fibersnHair thickening fibers blend with natural hairnHelps create thicker, fuller-looking hairnHair Thickening Fibers are Keratin Proteins similar to natural hair. Hair Thickening Fibers blend with natural hair that may add density and help create thicker, fuller-looking hair. Provides instant results, can be used daily while your natural hair grows. Directions: Hair must be completely dry. Brush or comb hair, shake or use brush applicator of Bossley Pro, apply liberally into thinning and low-density areas and gently style hair into place.