Jerome Russell Spray on Hair Color Thickener Black and Dark Brown Hair Color Thickener is the spray on answer to thinning hair! It easily covers small to medium size bald spots and it fills in thinning areas of hair. Covering grey hair is also simple with this product. Hair Color Thickener is easy to use and saves you time. Just spray on your favorite color where needed and you are all set to go for the day. No runny mess from colored hair dye kits. The color shampoos out the next time you wash your hair.