I have red hair so can I use sun in for it or will it ruin it???
Don't use sun in! Unless your hair is na bturally blonde you risk having your hair turn orange like bimbo the clown. It would be a much better idea to go to a salon and have your hair professionally done. A friend of mine used sun in and her hair turned a totally gross shade of orange, and she had dirty blonde hair. Basically sun in is such pure peroxide, and if there are any kind of red in your hair it turns orange. I tried to myself and ended up looking like bimbo the clown.
It won't make your hair blonde, but more light red and brassy - use with caution.
Yeah, my mom used it on red hair and it worked fine.