Human keratin, specifically the type used in hair care products to repair damage, is derived from human hair.
Unlike many other keratins used in various industries which are often animal byproducts (e.g., from wool, feathers, or horns), the human keratin discussed in the provided reference is sourced directly from human hair. The purpose of using human keratin is to ensure compatibility with human hair and to effectively target and repair damage sites along the hair shaft. The rationale is that it provides a direct and targeted approach to hair repair, as it's structurally similar to the hair it's intended to heal. This contrasts with animal-derived keratins, which may have different amino acid profiles and thus be less effective at bonding with and repairing human hair.
