Evaluation of Biological Activity and Thermal Stability of Epidermal Growth Factor (EGF) in Cosmetic Compositions

Epidermal Growth Factor (EGF) is a potent mitogenic polypeptide that plays a critical role in cell proliferation, differentiation, and tissue regeneration.However, the EGF's thermal instability in cosmetic formulations remains a major challenge for maintaining its biological efficacy during storage.This study evaluated the cell proliferation activity, collagen synthesis-promoting ability, and thermal stability four glycerin-based cosmetic compositions (Compositions A-D).Human dermal fibroblasts (HDF) were treated with EGF at concentrations of 0-4.0 ng/mL.Cell proliferation was assessed using the MTS assay, and collagen synthesis was quantified by measuring procollagen type I C-peptide (PIP) using an enzyme immunoassay kit.Thermal stability was evaluated after 15 days of storage at 4℃ and 30℃ (accelerated condition) using high-performance liquid chromatography (HPLC).All data are expressed as the mean ± standard deviation of at least three independent experiments.EGF treatment significantly enhanced HDF proliferation in a dose-dependent manner, reaching approximately 200% at 2.0-4.0 ng/mL.At 4.0 ng/mL, the relative procollagen type I (PIP) quantity reached approximately 134.5% of the PBS control, corresponding to an increase in collagen synthesis of approximately 34.5%.Thermal stability analysis showed that after 15 days at 30℃, native rhEGF purity decreased from an initial 98.56% to 32.99% in buffer alone and to 24.55% in Composition A. In contrast, Compositions B, C, and D maintained purities above 95%.These results show that EGF effectively promotes fibroblast proliferation and collagen biosynthesis, and that specific stabilizing compositions significantly enhance EGF thermal stability in cosmetic formulations.