Just For Men Shampoo-In Color Real Black H55 is a hair dye designed to restore your natural hair color by targeting gray hairs. The ammonia-free formula is enriched with keratin, olive oil, and vitamin E to nourish your hair while coloring. This easy-to-apply, shampoo-in formula works in just 5 minutes and provides natural-looking results that last up to 8 weeks, or until gray hair grows back.​