Truth: There are several types of moisturizers you can choose from, according to your skin's needs. Humectants, such as glycerin and lactic acid, attract water and help skin retain moisture. Emollients, such as fatty acids and ceramides, soften and soothe. Occlusives (known as “barrier creams”), such as petrolatum, dimethicone or lanolin, leave a film on the surface of the skin and seal in moisture.