They are available in such forms as creams, lotions, bath oils, ointment, and pastes. Creams are preparations of oil in water. The main component of a cream is water, making them effective for hydrating the skin. Lotions are comprised of powder crystals dissolved in water. They are held in suspension by surface active agents.
Lotions produce a coolant effect on the skin, as they hydrate the skin.
Bath oils are mixed with tap water, and their hydration properties are not much different than tap water itself. Ointments are comprised of water in an oil base. Typical oil components are either lanolin or petrolatum. Ointments are generally characterized by their occlusive properties. Pastes are created when powders are added to ointments.