What is keratin?

Keratin is a fundamental structural protein that plays a crucial role in forming the basic structure of hair, skin, and nails. It is a key component that provides strength and resilience to these tissues. This fibrous protein is essential for the protective qualities of hair follicles and contributes to the overall health and stability of the skin, as well as providing rigidity to nails. Understanding keratin's role in the anatomy of hair and skin is vital for cosmetology professionals, as it informs practices in haircare and skincare treatments. The other options relate to cosmetic ingredients, hair treatments, and minerals, but they do not accurately define what keratin is at a biological level.