Hint: It's not protein that you're eating that's the problem. If protein is a building block of hair, it can only be a good thing to load up on lots of products that contain protein, right? Popular hair repair options these days include keratin, collagen, peptides and bond-building complexes that claim to improve the health of your hair. But don’t load up on them too fast ... While protein helps maintain strong, healthy hair, strands can actually become stiff and brittle when topically applied