Lotion

A lotion is a low-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 brush, a clean cloth, cotton wool, or gauze. While lotion may be used as a medicine delivery system, many lotions, especially hand lotions and body lotions are meant instead to simply smooth, moisturize and soften the skin. These may be used in anti-aging lotions, which can also be classified as a cosmetic in many cases, and may contain fragrances. The Food and Drug Administration voiced concern about lotions not classified as drugs that advertise anti-aging or anti-wrinkle properties.

Dermatologists can prescribe lotions to treat or prevent skin diseases.[1] It is not unusual for the same drug ingredient to be formulated into a lotion, cream and ointment. Creams are the most convenient of the three but are inappropriate for application to regions of hairy skin such as the scalp, while a lotion is less viscous and may be readily applied to these areas (many medicated shampoos are in fact lotions). Historically, lotions also had an advantage in that they may be spread thinly compared to a cream or ointment and may economically cover a large area of skin, but product research has steadily eroded this distinction. Non-comedogenic lotions are recommended for use on acne prone skin.

Lotions can be used for the delivery to the skin of medications such as:

Antibiotics
Antiseptics
Antifungals
Corticosteroids
Anti-acne agents
Soothing, smoothing, moisturizing or protective agents (such as calamine)

There is currently no regulation over use of the term "hypoallergenic", and even pediatric skin products with the label were found to still contain allergens. Those with eczema are especially vulnerable to an allergic reaction with lotion, as their compromised skin barrier allows preservatives to bind with and activate immune cells.

The American Academy of Allergy, Asthma, and Immunology warns that lotion containing ingredients commonly found in food (such as goats milk, cow's milk, coconut milk, or oil) may introduce new allergies, and an allergic reaction when those foods are later consumed.

A 2015 study funded by the California Breast Cancer Research Program found that parabens, a common ingredient in cosmetic lotions, stimulate breast cancer cell proliferation.