Penetration of Different Molecular Weight Hydrolysed Keratins into Hair Fibres and Their Effects on the Physical Properties of Textured Hair

The study investigated the penetration and effects of hydrolyzed keratins of different molecular weights on textured hair. It found that low-MW keratins (221 Da) penetrated the hair cortex effectively, increasing hair volume and improving tensile strength and elasticity. Mid-MW keratins (2577 Da) also penetrated deeply, enhancing hair stiffness and reducing breakage, especially at high humidity. High-MW keratins (75,440 Da) mostly adsorbed onto the hair surface, forming a protective film and repairing damage in freshly relaxed hair. The findings suggested that using lower and mid-MW hydrolyzed keratins in hair care products could enhance the physical properties of textured hair, making it healthier and stronger.