INCI Name: Hydrolyzed Keratin
CAS Numbers: 69430-36-0
Keratin is a fibrous structural protein found in hair, skin, and nails, and found in animals as well. It is usually the key ingredient in salon and at-home hair straighteners and smoothers. On its own, it does not straighten hair, but together with other ingredients and heat from a flat iron, it can superficially bond with hair proteins to smooth the hair and reduce frizz.
Keratin is used in hair treatments usually applied in salons, however, some home treatments are also available.