Moisturizers are substances that increase the water content of the outer layer of the epidermis - the stratum corneum. Essentially, an emollient is an agent used to soften and smooth skin. This increases its flexibility and leaves it feeling soft and refreshed, while preventing dehydration.
Moisturizers can be used to temporarily protect the skin from dryness and repair the appearance of dry skin caused by low humidity, extremes in temperature, harsh winds, overexposure to sunlight, and other natural occurrences.
Moisturizers can also provide a barrier against harmful environmental substances such as pollutants and allergens. The main ingredients for moisturizing lotions are water and oil-based lubricants. In cosmetic terms, these are called humectants.