Kentucky Cosmetology State Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Glycerin is a highly effective ingredient commonly used for skin hydration in both skincare products and cosmetics because of its ability to attract moisture from the environment into the skin. This humectant draws water to the skin's surface, helping to maintain hydration levels and improve overall skin texture. Glycerin is well-tolerated by most skin types, including sensitive skin, making it a popular choice in formulations intended for moisturizing purposes.

In contrast, sodium sulfate is primarily used as a drying agent or to regulate the consistency of products rather than for hydration. Parabens are preservatives that prevent the growth of bacteria and mold in cosmetics, but they do not serve a moisturizing function. Similarly, alcohol can often be drying to the skin, especially in high concentrations, as it can strip natural oils. Thus, glycerin stands out as the go-to ingredient for achieving and maintaining skin hydration effectively.