Hair Masks Based on Keratin and Collagen

The study aimed to develop and characterize some O/W emulsions, designed as nourishing hair masks. The cosmetic formulations based on collagen hydrolysate, keratin, and natural ingredients (essential and vegetable oils) were organoleptically evaluated. The pH, morphological, superficial, and rheological properties were assessed as a physicochemical background. The rheological measurements were performed at 23 and 32°C, and the shear stress versus shear rate ascending and descending rheograms were built, together with the flow profiles of viscosity as a function of shear rate. The cosmetic emulsions were stable at temperature variation and the pH values were considered physiologically acceptable for the skin, indicating that formulations can be safely applied for cosmetic purposes. Results from the optical microscopy analysis showed that all emulsions presented a creamy and non-greasy appearance. The superficial profiles, quantified through contact angle at solid/liquid interface, were specific for hydrophilic formulations. The emulsions showed pseudoplastic and thixotropic behavior, facilitating the formulations' flow and the topical application. The Power law model was used to quantify the flow properties, and the thixotropic analysis was conducted using particular descriptors, namely thixotropic area, and thixotropic index. The designed emulsions presented appropriate physicochemical properties for cosmetic applications in hair care.