Hydrolyzed Keratin is a mixture of low- to medium-molecular-weight peptides produced by controlled hydrolysis of keratin (commonly from wool). As a film-former, humectant, and skin-conditioning agent, it integrates easily into the aqueous phase of emulsions and gels, depositing a breathable peptide network that helps retain water on the stratum corneum and refines skin feel. In leave-on skincare, this peptide film can improve perceived smoothness and comfort; early clinical work also suggests that keratin hydrolysates incorporated into topical bases can increase skin hydration and support barrier measurements versus vehicle controls. Because the peptides are amphiphilic, they can stabilize interfaces modestly and cooperate with primary emulsifiers to enhance product texture without heavy occlusion.

In haircare, hydrolyzed keratin is prized for substantivity and mechanical support on damaged fibers. Peptides adsorb to the cuticle, help reduce static/flyaways (antistatic function), and—depending on molecular weight—either plate out on the surface to smooth and protect or partially penetrate into the cortex to aid flexibility. Multiple studies indicate that higher-MW fractions excel at film-forming “repair aesthetics,” whereas lower-MW peptides may influence volume and internal feel; microscopy and fluorescence assays corroborate deposition and limited penetration. Practically, this translates to improved wet/dry combability, reduced breakage under stress, and better style retention when hydrolyzed keratin is paired with cationic polymers, oils/esters, and heat/UV-care claims in shampoos, rinse-off conditioners, masks, and leave-ins.