Development of Cosmetic Formulations Containing Olive Extract and <i>Spirulina</i> sp.: Stability and Clinical Efficacy Studies

Abstract

Cosmetic formulations with natural antioxidants can reduce the oxidative stress caused by solar radiation and pollution. In this context, the aim of this study was to develop and evaluate the clinical efficacy of cosmetic formulations containing olive extract (OE) and Spirulina sp. (SP). For this, rheological behavior, texture, and sensory properties were evaluated. In addition, 31 healthy women with an age of 39 to 60 years, with skin phototypes II and III, and the presence of signs of photoaging on the face were recruited and divided in Group 1 (vehicle formulation) and Group 2 (vehicle with active substances) for this clinical efficacy study. Both groups applied sunscreen daily during the day. The formulations showed non-Newtonian pseudoplastic behaviors and good sensory properties. The clinical evaluation using instrumental measurements showed an increase in skin hydration, an improvement of the skin barrier, and morphological characteristics of the epidermis after 12 weeks of application of the formulations. There was a significant increase in the brightness of the stratum corneum, which suggested a film-forming effect. In addition, both groups had an improvement in the dermis echogenicity, due to the use of sunscreens. Finally, the proposed formulation was effective in protecting the skin and reducing skin changes related to photoaging.

Keywords

• reflectance confocal microscopy
• rheology
• skin barrier
• film-forming effect
• skin photoaging
• texture profile