Too much protein will cause hair to break because the strands become stiff from strengthening themselves from the protein. This is why it is advised to follow up protein treatments with moisture. It's the same as if you lifted weights all of the time w/o stretching. Your body becomes rigid and lacks the flexibility needed to prevent injury. It's the same with hair. The protein is the muscle, the moisture is the flexibility, and the injury is breakage.
3b/c, medium-coarse, low porosity, low density
HG: Jessicurl Too Shea and Kinky Curly Curling Custard
Shampoo: nonsulfate shampoo and Suave Naturals sulfate shampoo when needed