Henna-ing This is definitely the most common practice but it turns the white or gray hair into orange which people now a days absolutely hate. So, really doesn't do much of a job. Also, using Lush Caca Noir also doesn't work on gray hair. I had suggested it to one of my friends but she confirmed that it didn't work on gray hair.
Hair Science and Home Remedies The hair which has already turned gray can never be turned black naturally. For that you will have to color the hair. But, you can always prevent new gray hairs from coming up. Also, gray hair is a lot of times hereditary so in such cases, its a little difficult to control. So, let me suggest some home remedies to PREVENT gray hair.