Investigation of Causal Relationships, Optimization and Quality Assessment of Herbal Sunscreen Formulation

Background: Herbal-based sunscreens are gaining popularity due to their ability to protect against ultraviolet (UV) rays and offer additional benefits such as moisturizing and anti-aging effects derived from bioactive compounds. Objectives: The present study aimed to investigate cause-effect relationships, optimize, and assess the quality of a herbal sunscreen formulated from Polypodium leucotomos, almond oil, Camellia sinensis, and Lycopersicum esculentum. Methods: A total of 19 sunscreen formulations were designed using BCPharSoft software and the D-optimal model. Independent variables included P. leucotomos leaves extract (X1), almond oil (X2), and a mixture of stearic acid and cetyl alcohol in a 1:1 ratio (X3). These variables were selected to enhance sun protection factor (SPF) and spreadability. Results: The optimized herbal sunscreen formulation consisted of 20% P. leucotomos leaves extract, 8% almond oil, and 5% stearic acid-cetyl alcohol mixture. The formulation achieved an SPF of 47.32 ± 0.66 and a spreadability of 28.17 ± 1.00 cm2, meeting established quality standards. Conclusions: This study contributes to advancements in natural cosmetics, meeting the growing demand for eco-friendly products and supporting the expansion of Vietnam's sunscreen market.