New Hampshire Cosmetology Practice Exam

Glycerin is a well-known humectant, meaning it draws moisture from the air and helps to retain it in the skin. It has the ability to attract water, which is crucial for hydration, making it an effective ingredient in moisturizers. Glycerin works by forming a protective layer on the skin, preventing moisture loss and keeping the skin plump and hydrated. This characteristic makes it a popular choice in many cosmetic and skincare formulations aimed at improving skin moisture levels.

In contrast, alcohol often has a drying effect on the skin, as it can strip away natural oils. Sulfates are primarily used for their cleansing properties and can be harsh on the skin, leading to irritation or dryness. Retinol, while beneficial for anti-aging and improving skin texture, does not primarily function as a moisturizer; it can sometimes lead to dryness, especially when first introduced into a skincare routine. Therefore, glycerin is recognized as the key moisturizing ingredient among the options listed.