Which ingredient is often used in skincare to help lock in moisture?

The ingredient that is often used in skincare to help lock in moisture is petrolatum. Petrolatum, commonly known as petroleum jelly, creates a barrier on the skin's surface that helps to prevent water loss. This occlusive property makes it an effective moisturizer, especially for dry or compromised skin. By forming a protective layer, it ensures that the hydration provided by other moisturizers can be retained, thereby boosting overall skin moisture levels.

In the context of skincare formulations, other ingredients listed serve different purposes. Alcohol can be drying and is often used for its astringent properties, which is not conducive to moisture retention. Parabens are preservatives used to extend the shelf life of products but do not provide any moisture-locking benefits. Emulsifiers are agents that help mix oil and water in formulations, but they do not specifically lock in moisture like petrolatum does.