Which ingredient is commonly used as a moisturizer in skin products?

Glycerin is commonly used as a moisturizer in skin products due to its chemical properties as a humectant. Humectants are substances that help retain moisture by attracting water from the air into the skin. This not only helps to keep the skin hydrated but also improves its overall appearance and texture. Glycerin is non-comedogenic, which means it won't clog pores, making it suitable for various skin types, including oily, dry, and sensitive skin.

In contrast, petrolatum and mineral oil can also be moisturizing, but they serve primarily as occlusive agents that create a barrier on the skin to prevent water loss rather than actively attracting moisture. Alcohol, while useful for its astringent properties and in some formulations, can actually be drying to the skin when used in higher concentrations, which is why it's not typically considered a moisturizing ingredient. This distinction highlights why glycerin is often favored in skin care products aimed at hydration.