I am 53 years, more than 50% hair has become gray which is not acceptable to me. I tried many hair dyes to make it black but all of those causes allergic ( skin ) reaction. Now I am using henna, but its red colour is also unaccetable. How can I make my hair black without causing any allergic reaction. What dye or herbal product or homemade goods or technique I can use to make my hair black without causing any allergic reaction.