How do protein conditioners work for hair?

Protein conditioners work by infusing hair with proteins that strengthen and repair damaged strands. These proteins, such as keratin, penetrate the hair shaft to help rebuild its structure and improve elasticity. By filling in gaps and enhancing moisture retention, protein conditioners can make hair appear smoother, shinier, and healthier. However, it's important to use them in moderation, as excessive protein can lead to stiffness or dryness.