Targets only the gray hair and replaces it with subtle tones that match your natural hair color. Easy as shampooing: No-drip formula works in 5 easy minutes. Rejuvenates hair: Vitamin enriched. Leaves hair thicker and fuller-looking. Ammonia-free formula wont damage hair. Lasts up to six weeks: Lasts until the gray grows back. Less than 50% gray? Use a shade thats one shade lighter than your natural hair color. More than 50% gray? Use the shade that matches your natural hair color.