Is there a hair product that does the opposite of Sun-in?

Like, something that makes your hair darker than it is, instead of lighter.Is there a hair product that does the opposite of Sun-in?
Wet your hair, over-gel your hair, dye it, and I'll have to find out what my friend uses 'cause it always looks a really dark brown instead of his normal brown coloured hair.Is there a hair product that does the opposite of Sun-in?
I wish I knew if you already used Sun-in or not! Hair color can make your hair darker. Haircolor comes in semi, demi and permanent varieties. If you have already used Sun-in or have highlights etc...you really need to go to a professional to get it back to natural. There are many semi-permanent colors available over the counter that would work if you are just trying to go a little darker, hope this helps.
Getting your hair glazed might enhance your color a bit.