1. A tough, fibrous protein that is the main structural component of hair, nails, and the outer layer of skin in vertebrates.
Usage: Usually used in plural form; also found in animal horns, hooves, and feathers
2. A protein used in hair care and cosmetic products to strengthen and smooth hair.
Usage: Common in shampoos, conditioners, and hair treatments

Examples

• Hair is made primarily of keratins, which give it strength and elasticity.
• Keratin treatments can help repair damaged hair and reduce frizz.
• Nails contain keratins that make them hard and protective.
• The outer layer of your skin contains keratins that form a protective barrier.
• Many shampoos now include keratins to improve hair health.
• Keratins are also found in animal horns and hooves.