My hair keeps breaking off.

I have dyed my hair only once in my entire life.

I also get a perm about once a year.

But my hair keeps splitting and breaking. The outer layers, especially at the back, are breaking off so much that the length is uneven. So even though I want to grow my hair out, it’s not easy. I keep holding it in, but I always end up cutting it anyway. Please recommend a hair supplement that can protect my hair and prevent breakage.