Is there a product that will make naturally red hair redder?

I have red hair but it's only like the top layer of my hair and when it's in a ponytail it looks really gross brown. Is there a product for your hair (except for John Frieda radiant red, it doesnr work on my hair) that isn't really a dye but will make my hair redder. I really need help because I'm scared my hair is losing it's color. Thanks!