Moisturizing agents are substances that help to hydrate and retain moisture in the skin. They work by forming a barrier on the skin's surface, preventing water loss and keeping the skin soft and supple. Common moisturizing agents include glycerin, hyaluronic acid, and shea butter, which are often found in lotions and creams. These agents can be classified into three main categories: humectants, emollients, and occlusives. Humectants, like aloe vera, attract water to the skin, while emollients, such as coconut oil, smooth and soften the skin. Occlusives, like petrolatum, create a protective layer to lock in moisture, making them essential for effective skin hydration.