keratine: Strengthening Your Hair, Skin, and Nails Keratin is a fundamental protein found in the cells of our skin, hair, and nails. It plays a vital role in maintaining the structural integrity of these tissues, ensuring they remain strong, resilient, and healthy. Although most people associate keratin with hair care products, its benefits extend far… keratine: The Key Protein for Healthy Hair, Skin, and Nails – Health and Fitness