Growth factors have been increasingly used as active cosmetic ingredients in recent years. The most commonly used is epidermal growth factor, which is naturally present in the skin and participates in skin regeneration. Therefore, it is frequently incorporated into cosmetic products intended for mature skin. However, its use in cosmetic products is primarily limited by its susceptibility to degradation and poor percutaneous absorption.
This thesis aimed to evaluate the content and stability of epidermal growth factor in selected cosmetic products and thereby verify compliance with the packaging claims. The study included ten cosmetic products covering different price ranges, all of which listed epidermal growth factor under the name sh-Oligopeptide-1 among their ingredients. For the determination of epidermal growth factor content, a previously developed high-performance liquid chromatography method was optimized and appropriately validated. Special attention was also paid to developing a sample preparation procedure.
Epidermal growth factor was not detected in any of the analysed cosmetic products. Therefore, compliance between the declared and the actual composition could not be confirmed. This means that the cosmetic products either do not contain the active ingredient or contain it at a level below the detection limit of the analytical method, namely less than 0.001% of epidermal growth factor in serums and less than 0.0025% in creams. It was also found that the labelling of epidermal growth factor in cosmetic products is accompanied by inconsistent terminology and an unclear definition of the ingredient.
The stability of epidermal growth factor was tested in various solvents and prepared serum samples under normal storage conditions. The results showed that its stability is affected by temperature, light, the solvent, and the excipients present in the cosmetic product. We found that epidermal growth factor is a highly unstable molecule, as its content in different samples decreased by at least 10% within a few days or even hours. In the final part of the study, the cosmetic products were supplemented with the active ingredient. Its content decreased by approximately 35% after two weeks of storage at room temperature, indicating pronounced instability and potentially explaining its absence from the tested cosmetic products. The findings of this study highlight the need for greater transparency in advertising, more appropriate regulation and increased monitoring of cosmetic products containing peptides and proteins as active ingredients.
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