Your hair is like a brillo pad because it lacks moisture.

Unless your body hair isn't growing then your hair is slow growing because you aren't retaining it because it lacks moisture.

There are very simple things you can do to rectify it.

Also just dumping a chemical on it won't solve the problem that your hair lacks moisture in fact it's more likely to make it worse.

Oh and when I relaxed my hair it was originally relaxed from natural. As I have fine low density hair the main issue was not over processing it.