The Best After Mixing Hair Dye How Long Is It Good For References. Web normally, a hair dye can last only half an hour after you mix it. The home colorists who prefer undergoing this procedure at home have to.

This is a question that many people ask when they are considering coloring their hair at home. But the dye wont last no longer than 30mins so you have to prepare everything before you mix. Coloring hair is simple only if you go to the colorist.