Dye over Previous Hair Color

Woman who is coloring her own hair
Photo: 26kot/Shutterstock
Q: I am thinking of dying my hair as close as I can get to my natural color (dark mousy blonde). In October of last year, I visited the local salon, and they dyed my hair a medium brown with a slightly red tint. As you can tell it has faded as much as it is going to by now, and my roots are about 2 inches long.
Could you tell me if by using a normal supermarket box dye, it would dye over the previous color? I also have a pre-lightener but when I did a strand test it went slightly ginger, and I heard that it is impossible to die over the ginger with another dye. I am also afraid of the pre-lightener ruining my hair. Thank you for your time and help.

A: You can dye over virtually any hair color provided the color you are going to is darker than the starting color. You do have to take into account the base color of the color used and the base color of the starting color to avoid any color conflicts, but these are less likely (and less likely to be serious) when going to a darker color.
In your case, you may be safe in using the box color, but there is a risk unless you know that the box color uses a base color that is compatible with the color you have already on your hair.
What I suggest is using hair color from the beauty supply shop instead of a kit. (Most kits don't offer information on the base color used.) You can pre-lighten the hair as needed to reach the level you need, and then you should condition the hair to protect it for the next stage of coloring.
The color you will choose should have a green base color (sometimes called "drab") by using a hair color with the green base color, you will counter any of the "ginger" that resulted from the pre-lightening stage and should get the desired color result.
You'll need to purchase both the hair color and a developer to combine with it. They should be mixed in equal parts. On the plus side, you can usually purchase the hair color and developer separately for less than the average cost of the hair color box kits.
If you are concerned about the strength of the pre-lightener and possible damage to the hair, be sure to condition your hair well before using the pre-lightener, and you may want to perform another strand test, then examine the dried test strand for signs of damage before proceeding. Please review our articles on hair coloring before you do anything, especially if you are unsure.
See also:
How to know the base color of hair
How to color hair
The basic hair color categories
The meaning of the numbers on hair dye boxes