Most of moisturizer helps attract water to the skin and seal it in; or prevent skin from losing water by coating it with a thick, impermeable layer. Petroleum jelly and moisturizing oils contain no water. They are best used while the skin is still damp after bathing to seal in moisture, which prolongs their skin-softening effect. Lotion and creams are emollients that contain basic ingredients of water and oil and can be used at any time to temporarily add moisture to the skin. Lotions and creams are less greasy and more cosmetically appealing than petroleum jelly or oils. Lotions have a thinner consistency than creams because they contain more water.