Applications of Spirulina Biomass in Cosmetics Processing: A Study on Antioxidant Activity and Formulation Stability

Spirulina (Limnospira) is a cyanobacterium rich in bioactive compounds, making it a sustainable and innovative biotechnological ingredient for the cosmetics industry. It meets the demand for non-animal-derived, multifunctional products for skin and hair care. In this study, Spirulina biomass was incorporated into shampoo (0.01%) and emulsion (5%) formulations, which, along with their respective controls, were subjected to cosmetic stability tests. Color, pH, and viscosity were analyzed at the initial time (T0) and after 24 h, 30, 60, and 90 days, with samples exposed to different storage conditions, including oven incubation, sunlight exposure, refrigeration, and shelf storage, to simulate diverse conservation environments. Microbiological parameters were assessed, and all samples complied with the specifications required for cosmetics. Antioxidant activity was also measured at baseline and after 90 days of storage. Results showed that incorporating Spirulina biomass, even at low concentrations, significantly enhanced antioxidant activity in both shampoo and emulsion formulations compared with controls. After 90 days, the samples maintained their stability in terms of appearance, color, odor, pH, and viscosity under sunlight, refrigeration, and shelf storage conditions. In contrast, samples exposed to elevated temperatures (45 °C) exhibited changes in color, pH, and viscosity. These findings demonstrate the feasibility of incorporating Spirulina biomass into cosmetic shampoo and emulsion bases, highlight potential changes during storage, and provide guidance for developing novel cosmetics that incorporate Spirulina as an ingredient.