What shampoo and conditioner or remedies do you reccomend?

I have really unhealthy hair, i mean reaaaaaaaally unhealthy hair. It used to be silky smooth a few years ago but then I kept damaging it and now it's so dry and frizzy and brittle and i have so many split ends. I also have thick hair. My hair is so wavy and curly. Could you please help me? Thank youu~