Among the following, which ingredient is commonly recognized as a humectant?

Glycerin is commonly recognized as a humectant due to its ability to attract moisture from the air into the skin or other surfaces, thereby helping to maintain hydration. Its effectiveness lies in its molecular structure, which allows it to bind water, making it a popular choice in skincare and cosmetic formulations aimed at moisturizing.

In contrast, petrolatum functions primarily as an occlusive agent, creating a barrier on the skin's surface to prevent moisture loss, rather than attracting moisture. Mineral oil also acts as an occlusive agent, coating the skin to lock in moisture rather than drawing it in. Emulsifying wax is primarily used to combine oil and water phases in formulations, and while it can aid in moisture retention, it does not have the same moisture-attracting properties as humectants like glycerin. Hence, glycerin stands out for its unique dual role in both attracting and retaining moisture, making it a key ingredient in effective hydration strategies.