A lotion is a low- to medium-viscosity topical preparation intended for application to unbroken skin. By contrast, creams and gels have higher viscosity. Lotions are applied to external skin with bare hands, a clean cloth, cotton wool or gauze. Many lotions, especially hand lotions and body lotions are formulated not as a medicine delivery system, but simply to smooth, re-hydrate, and soften the skin.
These are particularly popular with the aging and aged demographic groups, and in the case of face usage, can also be classified as a cosmetic in many cases, and may contain fragrances.
Most lotions are oil-in-water emulsions using a substance such as cetearyl alcohol to keep the emulsion together, but water-in-oil lotions are also formulated. The key components of a skin care lotion, cream or gel emulsion (that is mixtures of oil and water) are the aqueous and oily phases, an emulgent to prevent separation of these two phases, and, if used, the drug substance or substances. A wide variety of other ingredients such as fragrances, glycerol, petroleum jelly, dyes, preservatives, proteins and stabilizing agents are commonly added to lotions.