Development of a Vitamin C Derivative Serum for Pre-Aging Skin: Raw Material Screening, Stability and Clinical Evaluation

Vitamin C (L-ascorbic acid) is a powerful antioxidant widely used in skin care. Its ability to counteract free radicals helps prevent signs of premature aging such as dullness, dark spots, sagging skin, enlarged pores, and wrinkles. However, pure form of vitamin C is difficult to formulate because of limitations in stability and penetration, making its derivatives a preferred alternative. This study aims to develop a pre-aging serum using a stable and potent vitamin C derivative. Screening of various vitamin C derivatives—sodium ascorbyl phosphate, ascorbyl glucoside, 3-O-ethyl ascorbic acid, and 3-glyceryl ascorbate—was conducted by evaluating antioxidant activity and stability. Antioxidant activity was assessed using the DPPH method, while stability was assessed under various conditions: room temperature, 45 °C, 50 °C, −4 °C, sunlight exposure, and xenon lamp irradiation. The most stable and potent derivative was incorporated into a serum formulation, which was further evaluated for its stability and efficacy. Efficacy test was conducted on 39 females under dermatological assessment using Mexameter® MX 18, Cutometer® Dual MPA 580, and Spectrophotometer CM600D, along with photography via Visia-CR and Antera ® 3D CS instruments after 28 days. The 3-O-ethyl ascorbic acid was selected as the best vitamin C derivative. Serum containing 10% 3-O-ethyl ascorbic acid demonstrated excellent stability and significantly reduced dark spots (4.25%), increased skin firmness (20.35%), skin elasticity (R2 3.08%, R5 15.19%, R7 11.55%) and skin brightness (4.49%), reduced pores (9.86%) and skin wrinkles (13.71%). The 3-O-ethyl ascorbic acid serum was proven to be stable, could brighten the skin, and reduced signs of pre-aging.