Food colorings are water soluble dyes that are commonly used to color your shampoo for marketing. Adding extra color to the shampoo formula will have no effect on your hair color.

i dont recomend it. just use lemon juis and blowdry your hair with it in it

I was a honey blond in my youth. Now in my 50's, I have tried on several occasions to have my hair professionally colored to try and get that shade back. The trouble is that my hair seems to grab ashy tones and the color never lasts. I have a lot of gray in front and my hair is on the drier side. The last coloring I had done was a foil that was supposed to give me carmel and buttery lowlights and highlights on my light bolnde hair. Well, they were barely noticeable and by the second shampoo they were completely gone. This cost me $120.00, plus $60.00 for special color retaining shampoo and conditioner. I have started mixing drops of food coloring with water in a spray bottle and spraying this on while my hair is still wet. It, at least gives me some color when I am desperate. (I use about 1/2 cup water as the base and start adding drops. I test the color on a small strand before using.) I suggest experimenting with the food coloring. At least it's cheap, won't damage your hair and easily washes out. By the way, I have tried the after shampoo glosses. They provide a little color and leave your hair either too soft, or too weighed down, depending on how much you rinse. Not the answer, at least for me.