Nevada State Board of Cosmetology Practice Exam

What ingredient is commonly used as a humectant in skin care?

1. Glycerin

2. Mineral oil

3. Lanolin

4. Petrolatum

The correct answer is: Glycerin

Glycerin is commonly recognized as an effective humectant in skin care products. Humectants are substances that attract moisture from the environment and help to retain it in the skin, thereby keeping the skin hydrated. Glycerin has the ability to bind water, which makes it particularly beneficial for maintaining skin moisture. This property is especially important in skin care formulations aimed at addressing dryness or dehydrated skin. Products containing glycerin can improve the skin's overall texture and appearance, contributing to a plump and healthy look. Its efficacy as a humectant is well-supported by both scientific research and practical application in cosmetic products. While mineral oil, lanolin, and petrolatum have their own properties — such as providing occlusive barriers and emollient benefits — they do not function primarily as humectants. Instead, they are more focused on preventing moisture loss or providing a protective layer on the skin rather than attracting moisture from the environment.